Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

Theaflavin Ingredients & Drug Interactions

by Life Extension

Theaflavin label
See full label image
Capsule Category: Botanical
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Theaflavin against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

Theaflavin is a dietary supplement by Life Extension with 1 active ingredient. Its ingredients are commonly taken for mental alertness and energy, heart health support, blood pressure and cholesterol.Based on those ingredients, 694 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Black Tea extract. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Theaflavin by Life Extension

Ask about any prescription or over-the-counter medication and we check it for interactions with Theaflavin by Life Extension — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Theaflavin by Life Extension

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 11, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

Theaflavin by Life Extension is a single-ingredient supplement: black tea extract in a capsule. Black tea is rich in polyphenols, compounds that give it its antioxidant and health-promoting properties.

The extract also naturally contains caffeine, which plays a role in several of the supplement's potential benefits and its interactions with medications.

Does it work?

Strong evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Strong

Clinical evidence supports at least one of this product's ingredients for its stated purpose.

Why this rating?
  • The label markets this product for: Mental alertness, heart health, and antioxidant support.
  • We looked for evidence on: Mental alertness, Cardiovascular disease (CVD), Coronary heart disease (CHD), Myocardial infarction (MI), Atherosclerosis, Hyperlipidemia — and 4 related terms.
  • The strongest evidence on file: Black Tea is rated "Likely Effective" for Mental alertness (Natural Medicines).
  • Also on file: Black Tea is rated "Possibly Effective" for Myocardial infarction (MI).
  • Also on file: Black Tea is rated "Insufficient Reliable Evidence To Rate" for Atherosclerosis, Cardiovascular disease (CVD), Coronary heart disease (CHD), Hyperlipidemia, and more.

The evidence in our data supports black tea extract for mental alertness—that one's likely effective. It's possibly effective for heart attack prevention, bone strength (osteoporosis), low blood pressure, and ovarian cancer risk, though the evidence is less established.

Keep in mind that most of these studies looked at black tea as a beverage, so how concentrated extract compares isn't always clear.

The evidence, ingredient by ingredient Black Tea

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Black tea extract is generally well tolerated in moderate amounts by healthy adults. The main side effects come from its caffeine: you might experience jitteriness, insomnia, nausea, tremors, stomach upset, or a racing heartbeat.

Rarely, some people have chest pain or irregular heartbeats, and anaphylaxis (a severe allergic reaction) is possible in those sensitive to caffeine. Black tea can also lower your potassium level.

During pregnancy, keep caffeine intake moderate—high amounts may be harmful—and check with your doctor or pharmacist about what's right for you. If you're breastfeeding, caffeine passes into breast milk, so moderate your intake to avoid overstimulating the baby.

Side effects, ingredient by ingredient Black Tea

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Black Tea.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; diabetes medications; lithium.
  • For scale: 694 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

If you take ephedrine, stop—this is a Major interaction and serious adverse effects are possible. For Moderate interactions, double-check any use of antidepressants (especially fluvoxamine), anti-seizure drugs like valproate, blood thinners like warfarin, stomach-acid reducers like cimetidine, antipsychotics like clozapine, disulfiram for alcohol dependence, or dipyridamole for heart testing.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with clinical evidence supporting its stated purpose. Major medication interactions have been identified, and safety information is well characterized.

Theaflavin works well for people looking to boost mental alertness and who have no medications that interact with caffeine. If you take ephedrine, any antidepressant, an anti-seizure drug, a blood thinner, or heart medications, check with your pharmacist first.

Pregnant or breastfeeding folks should talk with their provider about whether this is a good fit.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Aug 23, 2020.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about Theaflavin, straight from the product label.

Brand Life Extension
Barcode (UPC) 737870130437
Net contents 30 Vegetarian Capsule(s)
Market status On market
Date entered into DSLD Aug 23, 2020
DSLD ID 231780
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Theaflavin by Life Extension, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Vegetarian Capsule(s)
Maximum serving Sizes:
1 Vegetarian Capsule(s)
UPC/BARCODE
737870130437
IngredientAmount% DV
Black Tea extract350 mg--

Other ingredients: Vegetable Cellulose, Stearic Acid, Silica

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
General Statements

Scan for product info

Suggested/Recommended/Usage/Directions

Read the entire label and follow the directions carefully prior to use. Directions: Take one (1) capsule daily with or without food, or as recommended by a healthcare practitioner. Take earlier in the day if you are sensitive to caffeine.

Formula

Each serving contains les than 8 mg of caffeine (the amount found in about a 1/8 cup brewed green tea).

Patented tea extract

Brand IP Statement(s)

This product contains a black tea extract which is licensed from Applied Food Sciences Inc. and is protected by U.S. Patent Nos. 6,811,766 and 6,602,527.

Precautions

Warnings: Keep out of reach of children.

Do not exceed recommended dose. Do not purchase if outer seal is broken or damaged.

When using nutritional supplements, please consult with your physician if you are undergoing treatment for a medical condition or if you are pregnant or lactating.

To report a serious adverse event or obtain product information, contact 1-866-280-2852.

Formulation

Standardized extract

Non-GMO

Seals/Symbols

Non GMO LE Certified

FDA Statement of Identity

Dietary Supplement

Storage

Store tightly closed in a cool, dry place.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Theaflavin by Life Extension label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

Theaflavin label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Theaflavin by Life Extension

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Vegetarian Capsule(s) Dosage formCapsule Amounts shown are per serving.

Black Tea extract

Interacts with
694 drugs
350 mg per serving Form: Theaflavins

Black tea is a popular caffeinated drink made from the fully oxidized leaves of the Camellia sinensis plant, and it contains caffeine and antioxidant...

Black Tea extract monograph & interactions

Other (inactive) ingredients: Vegetable Cellulose, Stearic Acid, Silica. These complete the product’s ingredient list but are not active constituents.

Interaction report

Theaflavin by Life Extension Drug Interactions

Want to check YOUR meds against Theaflavin?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

 Go to the checker
694Drugs
8 Major 572 Moderate 114 Minor

Ingredients driving the most interactions

Black Tea extract 694

Individual Drug Interactions

The ingredients in Theaflavin interact with 694 drugs. Click any drug to see the details.

1 of the 1 ingredient in Theaflavin interact with drugs. Each result below shows which ingredient is responsible. Black Tea extract

Each ingredient & the kinds of drugs it affects

For each ingredient in Theaflavin with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

Black Tea extract46 drug types · 694 drugs

Ephedrine

Theoretically, concomitant use might increase the risk for simulant adverse effects.
Black tea contains caffeine. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death. Tell patients to avoid taking caffeine with ephedrine and other stimulants.

Likelihood Probable Evidence D
Adenosine (Adenocard)

Theoretically, black tea might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.
Black tea contains caffeine. Caffeine is a competitive inhibitor of adenosine at the cellular level. However, caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine. It is recommended that methylxanthines such as caffeine, as well as methylxanthine-containing products, be stopped 24 hours prior to pharmacological stress tests. However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Likelihood Possible Evidence B
Anticoagulant/Antiplatelet Drugs

Theoretically, black tea may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
Black tea contains caffeine. Caffeine is reported to have antiplatelet activity. Theoretically, the caffeine in black tea might increase the risk of bleeding when used concomitantly with antiplatelet drugs. However, this interaction has not been reported in humans.

Likelihood Possible Evidence D
Beta-Adrenergic Agonists

Theoretically, concomitant use of large amounts of black tea might increase cardiac inotropic effects of beta-agonists.
Black tea contains caffeine. Caffeine can increase cardiac inotropic effects of beta-agonists.

Likelihood Probable Evidence D
Carbamazepine (Tegretol)

Theoretically, black tea might reduce the effects of carbamazepine and increase the risk for convulsion.
Black tea contains caffeine. Animal research suggests that caffeine can lower the anticonvulsant effects of carbamazepine and can induce seizures when taken in doses above 400 mg/kg. Human research has shown that taking caffeine 300 mg in three divided doses along with carbamazepine 200 mg reduces the bioavailability of carbamazepine by 32% and prolongs the plasma half-life of carbamazepine 2-fold in healthy individuals.

Likelihood Possible Evidence B
Cimetidine (Tagamet)

Theoretically, concomitant use might increase the effects and adverse effects of caffeine in black tea.
Black tea contains caffeine. Cimetidine can reduces caffeine clearance by 31% to 42%.

Likelihood Likely Evidence B
Clozapine (Clozaril)

Theoretically, black tea might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.
Concomitant administration of black tea and clozapine might theoretically cause acute exacerbation of psychotic symptoms due to the caffeine in black tea. Caffeine can increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg daily inhibit clozapine metabolism. Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Researchers speculate that caffeine might inhibit CYP1A2. However, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients be more sensitive to the interaction between clozapine and caffeine.

Likelihood Possible Evidence B
Contraceptive Drugs

Theoretically, concomitant use might increase the effects and adverse effects of caffeine found in black tea.
Black tea contains caffeine. Oral contraceptive drugs can decrease caffeine clearance by 40% to 65%.

Likelihood Probable Evidence B
Cytochrome P450 1A2 (Cyp1A2) Inhibitors

Theoretically, concomitant use might increase the levels and adverse effects of caffeine.
Black tea contains caffeine. Caffeine is metabolized by CYP1A2,. Theoretically, drugs that inhibit CYP1A2 may decrease the clearance rate of caffeine from black tea and increase caffeine levels.

Likelihood Possible Evidence D
Dipyridamole (Persantine)

Theoretically, black tea might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.
Black tea contains caffeine. Caffeine is a methylxanthine that may inhibit dipyridamole-induced vasodilation. It is recommended that methylxanthines such as caffeine, as well as methylxanthine-containing products such as black tea, be stopped 24 hours prior to pharmacological stress tests. Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing.

Likelihood Probable Evidence B
Disulfiram (Antabuse)

Theoretically, disulfiram might increase the risk of adverse effects from caffeine.
Black tea contains caffeine. In human research, disulfiram decreases the clearance and increases the half-life of caffeine.

Likelihood Probable Evidence B
Diuretic Drugs

Theoretically, using black tea with diuretic drugs might increase the risk of hypokalemia.
Black tea contains caffeine. Caffeine, especially in excessive amounts, can reduce potassium levels due to stimulation of the sodium-potassium pump. Diuretics can also cause lower potassium levels.

Likelihood Possible Evidence D
Estrogens

Theoretically, estrogens might increase the levels and adverse effects of caffeine.
Black tea contains caffeine. Estrogen inhibits caffeine metabolism.

Likelihood Probable Evidence B
Ethosuximide (Zarontin)

Theoretically, black tea might reduce the effects of ethosuximide and increase the risk for convulsions.
Black tea contains caffeine. Animal research suggests that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide. However, this effect has not been observed in humans.

Likelihood Possible Evidence D
Felbamate (Felbatol)

Theoretically, black tea might reduce the effects of felbamate and increase the risk for convulsions.
Black tea contains caffeine. Animal research suggests that a high dose of caffeine 161.7 mg/kg can decrease the anticonvulsant activity of felbamate. However, this effect has not been observed in humans.

Likelihood Possible Evidence D
Flutamide (Eulexin)

Theoretically, black tea might increase the levels and adverse effects of flutamide.
Black tea contains caffeine. In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide. Theoretically, concomitant use of caffeine and flutamide might increase serum concentrations of flutamide and increase the risk of adverse effects.

Likelihood Possible Evidence D
Fluvoxamine (Luvox)

Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.
Black tea contains caffeine. Fluvoxamine reduces caffeine metabolism.

Likelihood Probable Evidence B
Lithium

Theoretically, abrupt black tea withdrawal might increase the levels and adverse effects of lithium.
Black tea contains caffeine. Abrupt caffeine withdrawal can increase serum lithium levels. Two cases of lithium tremor that worsened with abrupt coffee withdrawal have been reported.

Likelihood Probable Evidence D
Monoamine Oxidase Inhibitors (Maois)

Theoretically, concomitant use might increase the risk of a hypertensive crisis.
Black tea contains caffeine. Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies. Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis. In a case report, a patient that consumed 10-12 cups of caffeinate coffee and took the MAOI tranylcypromine presented with severe hypertension. Hypertension was resolved after the patients switched to drinking decaffeinated coffee.

Likelihood Possible Evidence D
Nicotine

Theoretically, concomitant use might increase the risk of hypertension.
Black tea contains caffeine. Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly.

Likelihood Probable Evidence B
Organic Anion-Transporting Polypeptide Substrates (Oatp)

Theoretically, black tea might reduce the absorption of organic anion-transporting polypeptide (OATP) substrates.
In vitro, black tea extract inhibits organic anion-transporting polypeptide (OATP)2B1. OATP2B1 is expressed in the small intestine and liver and is responsible for the uptake of drugs and other compounds. In an animal model, black tea extract was found to inhibit the absorption of rosuvastatin, a substrate of OATP2B1. However, this effect has not been reported in humans.

Likelihood Possible Evidence D
Pentobarbital (Nembutal)

Theoretically, black tea might decrease the effects of pentobarbital.
Black tea contains caffeine. Theoretically, caffeine might negate the hypnotic effects of pentobarbital.

Likelihood Possible Evidence B
Phenobarbital (Luminal)

Theoretically, black tea might reduce the effects of phenobarbital and increase the risk for convulsions.
Black tea contains caffeine. Animal research suggests that caffeine can decrease the anticonvulsant activity of phenobarbital. The exact mechanism of this interaction is unclear.

Likelihood Possible Evidence D
Phenylpropanolamine

Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.
Black tea contains caffeine. Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure. Phenylpropanolamine also seems to increase caffeine serum levels.

Likelihood Probable Evidence B
Phenytoin (Dilantin)

Theoretically, black tea might reduce the effects of phenytoin and increase the risk for convulsions.
Black tea contains caffeine. Animal research suggests that caffeine can decrease the anticonvulsant activity of phenytoin. The effect does not seem to be related to the seizure threshold-lowering effects of caffeine. However, the exact mechanism of this interaction is unclear.

Likelihood Possible Evidence D
Black Tea extract full monograph & all 46 interactions
The maker

Brand information

Manufacturer and brand details for Theaflavin, from the product label.

Life Extension

See all Life Extension products
Name
Quality Supplements and Vitamins, Inc.
City
Ft. Lauderdale
State
FL
ZipCode
33309
Phone Number
1-866-280-2852
Web Address
LifeExtension.com
Pharmacist Counseling Corner

Theaflavin by Life Extension: Common Questions

Does Theaflavin by Life Extension interact with any medications?
Yes. Based on its ingredients, Theaflavin has a known interaction with 694 medications, including 8 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Theaflavin contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take this if I'm pregnant?
There isn't enough data on file about black tea extract safety in pregnancy. Because it contains caffeine, and high caffeine intake during pregnancy may be harmful, talk with your doctor or pharmacist about what's safe for you personally. They can give you guidance based on your situation.
Can I take this while breastfeeding?
Caffeine from black tea passes into breast milk. To avoid overstimulating your baby, keep your intake moderate and discuss it with your doctor or pharmacist to find the right amount for you.
What are the most common side effects?
Most side effects come from the caffeine: jitteriness, insomnia, nausea, stomach irritation, tremors, and a racing heartbeat. These usually happen when you take more than moderate amounts.
Does it really help with heart attack prevention?
The evidence suggests it's possibly effective for that, but it's not proven yet. Most research on black tea and heart health comes from studies of the beverage itself, so how a concentrated extract compares isn't entirely clear.
Will this work for memory and focus?
For mental alertness, the evidence is solid—black tea extract is likely effective for that. You should notice a boost in focus and alertness, though individual results vary.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

Theaflavin label
Go deeper

The Full Monographs Behind Theaflavin’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Black Tea

Interacts with 694 drugs

Black tea is a popular caffeinated drink made from the fully oxidized leaves of the Camellia sinensis plant, and it contains caffeine and antioxidant plant compounds. Moderate tea drinking i...

Read the full Black Tea monograph →
Sources

Sources & How We Checked

Theaflavin's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 150 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Black Tea 150 references
  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Hertog MGL, Sweetnam PM, Fehily AM, et al. Antioxidant flavonols and ischemic heart disease in a Welsh population of men: the Caerphilly Study. Am J Clin Nutr 1997;65:1489-94. PubMed
  3. Harder S, Fuhr U, Staib AH, Wolff T. Ciprofloxacin-caffeine: a drug interaction established using in vivo and in vitro investigations. Am J Med 1989;87:89S-91S. PubMed
  4. Carbo M, Segura J, De la Torre R, et al. Effect of quinolones on caffeine disposition. Clin Pharmacol Ther 1989;45:234-40. PubMed
  5. Healy DP, Polk RE, Kanawati L, et al. Interaction between oral ciprofloxacin and caffeine in normal volunteers. Antimicrob Agents Chemother 1989;33:474-8. PubMed
  6. Mester R, Toren P, Mizrachi I, et al. Caffeine withdrawal increases lithium blood levels. Biol Psychiatry 1995;37:348-50. PubMed
  7. Jefferson JW. Lithium tremor and caffeine intake: two cases of drinking less and shaking more. J Clin Psychiatry 1988;49:72-3.
  8. Lasswell WL Jr, Weber SS, Wilkins JM. In vitro interaction of neuroleptics and tricylic antidepressants with coffee, tea, and gallotannic acid. J Pharm Sci 1984;73:1056-8. PubMed
  9. Kulhanek F, Linde OK, Meisenberg G. Precipitation of antipsychotic drugs in interaction with coffee or tea. Lancet 1979;2:1130.
  10. Merhav H, Amitai Y, Palti H, Godfrey S. Tea drinking and microcytic anemia in infants. Am J Clin Nutr 1985;41:1210-3.
  11. Joeres R, Klinker H, Heusler H, et al. Influence of mexiletine on caffeine elimination. Pharmacol Ther 1987;33:163-9. PubMed
  12. Vahedi K, Domingo V, Amarenco P, Bousser MG. Ischemic stroke in a sportsman who consumed MaHuang extract and creatine monohydrate for bodybuilding. J Neurol Neurosurg Psychiatr 2000;68:112-3.
  13. Wakabayashi K, Kono S, Shinchi K, et al. Habitual coffee consumption and blood pressure: A study of self-defense officials in Japan. Eur J Epidemiol 1998;14:669-73. PubMed
  14. Hodgson JM, Puddey IB, Burke V, et al. Effects on blood pressure of drinking green and black tea. J Hypertens 1999;17:457-63. PubMed
  15. Rapuri PB, Gallagher JC, Kinyamu HK, Ryschon KL. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr 2001;74:694-700. PubMed
  16. The National Toxicology Program (NTP). Caffeine. Center for the Evaluation of Risks to Human Reproduction (CERHR). Available at: http://cerhr.niehs.nih.gov/common/caffeine.html.
  17. Klebanoff MA, Levine RJ, DerSimonian R, et al. Maternal serum paraxanthine, a caffeine metabolite, and the risk of spontaneous abortion. N Engl J Med 1999;341:1639-44. PubMed
  18. Eskenazi B. Caffeine—filtering the facts. N Engl J Med 1999;341:1688-9. PubMed
  19. Fernandes O, Sabharwal M, Smiley T, et al. Moderate to heavy caffeine consumption during pregnancy and relationship to spontaneous abortion and abnormal fetal growth: a meta-analysis. Reprod Toxicol 1998;12:435-44. PubMed
  20. Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40. PubMed
  21. Nurminen ML, Niittynen L, Korpela R, Vapaatalo H. Coffee, caffeine and blood pressure: a critical review. Eur J Clin Nutr 1999;53:831-9. PubMed
  22. Dews PB, Curtis GL, Hanford KJ, O'Brien CP. The frequency of caffeine withdrawal in a population-based survey and in a controlled, blinded pilot experiment. J Clin Pharmacol 1999;39:1221-32. PubMed
  23. FDA. Proposed rule: dietary supplements containing ephedrine alkaloids. Available at: www.verity.fda.gov (Accessed 25 January 2000).
  24. Weisburger JH. Tea and health: the underlying mechanisms. Proc Soc Exp Biol Med 1999;220:271-5. PubMed
  25. Briggs GB, Freeman RK, Yaffe SJ. Drugs in Pregnancy and Lactation. 5th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 1998.
  26. Hagg S, Spigset O, Mjorndal T, Dahlqvist R. Effect of caffeine on clozapine pharmacokinetics in healthy volunteers. Br J Clin Pharmacol 2000;49:59-63. PubMed
  27. Watson JM, Jenkins EJ, Hamilton P, et al. Influence of caffeine on the frequency and perception of hypoglycemia in free-living patients with type 1 diabetes. Diabetes Care 2000;23:455-9. PubMed
  28. Lloyd T, Johnson-Rollings N, Eggli DF, et al. Bone status among postmenopausal women with different habitual caffeine intakes: a longitudinal investigation. J Am Coll Nutr 2000;19:256-61. PubMed
  29. American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 2001;108:776-89. PubMed
  30. Sinclair CJ, Geiger JD. Caffeine use in sports. A pharmacological review. J Sports Med Phys Fitness 2000;40:71-9.
  31. Haller CA, Benowitz NL. Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. N Engl J Med 2000;343:1833-8. PubMed
  32. Ali M, Afzal M. A potent inhibitor of thrombin stimulated platelet thromboxane formation from unprocessed tea. Prostaglandins Leukot Med 1987;27:9-13. PubMed
  33. Ardlie NG, Glew G, Schultz BG, Schwartz CJ. Inhibition and reversal of platelet aggregation by methyl xanthines. Thromb Diath Haemorrh 1967;18:670-3. DOI
  34. Olthof MR, Hollman PC, Zock PL, Katan MB. Consumption of high doses of chlorogenic acid, present in coffee, or of black tea increases plasma total homocysteine concentrations in humans. Am J Clin Nutr 2001;73:532-8. PubMed
  35. Hartman TJ, Tangrea JA, Pietinen P, et al. Tea and coffee consumption and risk of colon and rectal cancer in middle-aged Finnish men. Nutr Cancer 1998;31:41-8. PubMed
  36. Ferrini RL, Barrett-Connor E. Caffeine intake and endogenous sex steroid levels in postmenopausal women. The Rancho Bernardo Study. Am J Epidemiol 1996:144:642-4. PubMed
  37. Bell DG, Jacobs I, Ellerington K. Effect of caffeine and ephedrine ingestion on anaerobic exercise performance. Med Sci Sports Exerc 2001;33:1399-403. PubMed
  38. Horner NK, Lampe JW. Potential mechanisms of diet therapy for fibrocystic breast conditions show inadequate evidence of effectiveness. J Am Diet Assoc 2000;100:1368-80. PubMed
  39. Bracken MB, Triche EW, Belanger K, et al. Association of maternal caffeine consumption with decrements in fetal growth. Am J Epidemiol 2003;157:456-66.. PubMed
  40. Shekelle PG, Hardy ML, Morton SC, et al. Efficacy and safety of ephedra and ephedrine for weight loss and athletic performance: a meta-analysis. JAMA 2003;289:1537-45.. PubMed
  41. McGowan JD, Altman RE, Kanto WP Jr. Neonatal withdrawal symptoms after chronic maternal ingestion of caffeine. South Med J 1988;81:1092-4.. PubMed
  42. Nehlig A, Debry G. Consequences on the newborn of chronic maternal consumption of coffee during gestation and lactation: a review. J Am Coll Nutr 1994;13:6-21.. PubMed
  43. Massey LK. Is caffeine a risk factor for bone loss in the elderly? Am J Clin Nutr 2001;74:569-70. PubMed
  44. Dreher HM. The effect of caffeine reduction on sleep quality and well-being in persons with HIV. J Psychosom Res 2003;54:191-8.. PubMed
  45. Kockler DR, McCarthy MW, Lawson CL. Seizure activity and unresponsiveness after hydroxycut ingestion. Pharmacotherapy 2001;21:647-51.. PubMed
  46. Nix D, Zelenitsky S, Symonds W, et al. The effect of fluconazole on the pharmacokinetics of caffeine in young and elderly subjects. Clin Pharmacol Ther 1992;51:183. DOI
  47. Greenblatt DJ, von Moltke LL, Perloff ES, et al. Interaction of flurbiprofen with cranberry juice, grape juice, tea, and fluconazole: in vitro and clinical studies. Clin Pharmacol Ther 2006;79:125-33. PubMed
  48. Infante S, Baeza ML, Calvo M, et al. Anaphylaxis due to caffeine. Allergy 2003;58:681-2. PubMed
  49. Massey LK, Whiting SJ. Caffeine, urinary calcium, calcium metabolism and bone. J Nutr 1993;123:1611-4. PubMed
  50. Nawrot P, Jordan S, Eastwood J, et al. Effects of caffeine on human health. Food Addit Contam 2003;20:1-30. PubMed
  51. May DC, Jarboe CH, VanBakel AB, Williams WM. Effects of cimetidine on caffeine disposition in smokers and nonsmokers. Clin Pharmacol Ther 1982;31:656-61. PubMed
  52. Abernethy DR, Todd EL. Impairment of caffeine clearance by chronic use of low-dose oestrogen-containing oral contraceptives. Eur J Clin Pharmacol 1985;28:425-8. PubMed
  53. Brown NJ, Ryder D, Branch RA. A pharmacodynamic interaction between caffeine and phenylpropanolamine. Clin Pharmacol Ther 1991;50:363-71. PubMed
  54. Sanderink GJ, Bournique B, Stevens J, et al. Involvement of human CYP1A isoenzymes in the metabolism and drug interactions of riluzole in vitro. Pharmacol Exp Ther 1997;282:1465-72. DOI
  55. Wahllander A, Paumgartner G. Effect of ketoconazole and terbinafine on the pharmacokinetics of caffeine in healthy volunteers. Eur J Clin Pharmacol 1989;37:279-83. PubMed
  56. Carrillo JA, Benitez J. Clinically significant pharmacokinetic interactions between dietary caffeine and medications. Clin Pharmacokinet 2000;39:127-53. PubMed
  57. Underwood DA. Which medications should be held before a pharmacologic or exercise stress test? Cleve Clin J Med 2002;69:449-50. PubMed
  58. Aqel RA, Zoghbi GJ, Trimm JR, et al. Effect of caffeine administered intravenously on intracoronary-administered adenosine-induced coronary hemodynamics in patients with coronary artery disease. Am J Cardiol 2004;93:343-6. PubMed
  59. Zheng XM, Williams RC. Serum caffeine levels after 24-hour abstention: clinical implications on dipyridamole (201)Tl myocardial perfusion imaging. J Nucl Med Technol 2002;30:123-7.
  60. Institute of Medicine. Caffeine for the Sustainment of Mental Task Performance: Formulations for Military Operations. Washington, DC: National Academy Press, 2001. Available at: http://books.nap.edu/books/0309082587/html/index.html. DOI
  61. Holmgren P, Norden-Pettersson L, Ahlner J. Caffeine fatalities--four case reports. Forensic Sci Int 2004;139:71-3. PubMed
  62. Dews PB, O'Brien CP, Bergman J. Caffeine: behavioral effects of withdrawal and related issues. Food Chem Toxicol 2002;40:1257-61. PubMed
  63. Beach CA, Mays DC, Guiler RC, et al. Inhibition of elimination of caffeine by disulfiram in normal subjects and recovering alcoholics. Clin Pharmacol Ther 1986;39:265-70. PubMed
  64. Sato J, Nakata H, Owada E, et al. Influence of usual intake of dietary caffeine on single-dose kinetics of theophylline in healthy human subjects. Eur J Clin Pharmacol 1993;44:295-8. PubMed
  65. Benowitz NL, Osterloh J, Goldschlager N, et al. Massive catecholamine release from caffeine poisoning. JAMA 1982;248:1097-8. DOI
  66. Leson CL, McGuigan MA, Bryson SM. Caffeine overdose in an adolescent male. J Toxicol Clin Toxicol 1988;26:407-15. PubMed
  67. Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology (Berl) 2004;176:1-29. PubMed
  68. Winkelmayer WC, Stampfer MJ, Willett WC, Curhan GC. Habitual caffeine intake and the risk of hypertension in women. JAMA 2005;294:2330-5. PubMed
  69. Raaska K, Raitasuo V, Laitila J, Neuvonen PJ. Effect of caffeine-containing versus decaffeinated coffee on serum clozapine concentrations in hospitalised patients. Basic Clin Pharmacol Toxicol 2004;94:13-8. DOI
  70. Forrest WH Jr, Bellville JW, Brown BW Jr. The interaction of caffeine with pentobarbital as a nighttime hypnotic. Anesthesiology 1972;36:37-41. PubMed
  71. Lake CR, Rosenberg DB, Gallant S, et al. Phenylpropanolamine increases plasma caffeine levels. Clin Pharmacol Ther 1990;47:675-85. PubMed
  72. Correa A, Stolley A, Liu Y. Prenatal tea consumption and risks of anencephaly and spina bifida. Ann Epidemiol 2000;10:476-7. PubMed
  73. Weng X, Odouli R, Li DK. Maternal caffeine consumption during pregnancy and the risk of miscarriage: a prospective cohort study. Am J Obstet Gynecol 2008;198:279.e1-8. PubMed
  74. Savitz DA, Chan RL, Herring AH, et al. Caffeine and miscarriage risk. Epidemiology 2008;19:55-62. PubMed
  75. Parker DL, Hoffmann TK, Tucker MA, et al. Interaction between warfarin and black tea. Ann Pharmacother 2009;43:150-1. PubMed
  76. Shet, M. S., McPhaul, M., Fisher, C. W., Stallings, N. R., and Estabrook, R. W. Metabolism of the antiandrogenic drug (Flutamide) by human CYP1A2. Drug Metab Dispos. 1997;25(11):1298-1303.
  77. Stille, W., Harder, S., Mieke, S., Beer, C., Shah, P. M., Frech, K., and Staib, A. H. Decrease of caffeine elimination in man during co-administration of 4-quinolones. J.Antimicrob.Chemother. 1987;20(5):729-734. PubMed
  78. Kot, M. and Daniel, W. A. Effect of diethyldithiocarbamate (DDC) and ticlopidine on CYP1A2 activity and caffeine metabolism: an in vitro comparative study with human cDNA-expressed CYP1A2 and liver microsomes. Pharmacol Rep. 2009;61(6):1216-1220. PubMed
  79. Gasior, M., Borowicz, K., Buszewicz, G., Kleinrok, Z., and Czuczwar, S. J. Anticonvulsant activity of phenobarbital and valproate against maximal electroshock in mice during chronic treatment with caffeine and caffeine discontinuation. Epilepsia 1996;37(3 PubMed
  80. Jankiewicz, K., Chroscinska-Krawczyk, M., Blaszczyk, B., and Czuczwar, S. J. [Caffeine and antiepileptic drugs: experimental and clinical data]. Przegl.Lek. 2007;64(11):965-967.
  81. Luszczki, J. J., Zuchora, M., Sawicka, K. M., Kozinska, J., and Czuczwar, S. J. Acute exposure to caffeine decreases the anticonvulsant action of ethosuximide, but not that of clonazepam, phenobarbital and valproate against pentetrazole-induced seizures i
  82. Chroscinska-Krawczyk, M., Jargiello-Baszak, M., Walek, M., Tylus, B., and Czuczwar, S. J. Caffeine and the anticonvulsant potency of antiepileptic drugs: experimental and clinical data. Pharmacol.Rep. 2011;63(1):12-18. PubMed
  83. Vaz, J., Kulkarni, C., David, J., and Joseph, T. Influence of caffeine on pharmacokinetic profile of sodium valproate and carbamazepine in normal human volunteers. Indian J.Exp.Biol. 1998;36(1):112-114.
  84. Gasior, M., Swiader, M., Przybylko, M., Borowicz, K., Turski, W. A., Kleinrok, Z., and Czuczwar, S. J. Felbamate demonstrates low propensity for interaction with methylxanthines and Ca2+ channel modulators against experimental seizures in mice. Eur.J Phar PubMed
  85. Mohiuddin, M., Azam, A. T., Amran, M. S., and Hossain, M. A. In vive effects of gliclazide and metformin on the plasma concentration of caffeine in healthy rats. Pak.J Biol Sci 5-1-2009;12(9):734-737.
  86. Mays, D. C., Camisa, C., Cheney, P., Pacula, C. M., Nawoot, S., and Gerber, N. Methoxsalen is a potent inhibitor of the metabolism of caffeine in humans. Clin.Pharmacol.Ther. 1987;42(6):621-626. PubMed
  87. Wojcikowski, J. and Daniel, W. A. Perazine at therapeutic drug concentrations inhibits human cytochrome P450 isoenzyme 1A2 (CYP1A2) and caffeine metabolism--an in vitro study. Pharmacol Rep. 2009;61(5):851-858. PubMed
  88. Daniel, W. A., Syrek, M., Rylko, Z., and Kot, M. Effects of phenothiazine neuroleptics on the rate of caffeine demethylation and hydroxylation in the rat liver. Pol.J Pharmacol 2001;53(6):615-621.
  89. Norager, C. B., Jensen, M. B., Weimann, A., and Madsen, M. R. Metabolic effects of caffeine ingestion and physical work in 75-year old citizens. A randomized, double-blind, placebo-controlled, cross-over study. Clin Endocrinol (Oxf) 2006;65(2):223-228. PubMed
  90. Wang, X. and Yeung, J. H. Effects of the aqueous extract from Salvia miltiorrhiza Bunge on caffeine pharmacokinetics and liver microsomal CYP1A2 activity in humans and rats. J Pharm Pharmacol 2010;62(8):1077-1083.
  91. Azcona O, Barbanoi MJ, Torrent J, Jane F. Evaluation of the central effects of alcohol and caffeine interaction. Br J Clin Pharmacol 1995;40:393-400. PubMed
  92. Harder S, Staib AH, Beer C, et al. 4-quinolones inhibit biotransformation of caffeine. Eur J Clin Pharmacol 1988;35:651-6. PubMed
  93. Zhang LL, Zhang JR, Guo K, et al. Effects of fluoroquinolones on CYP4501A and 3A in male broilers. Res Vet Sci 2011;90:99-105. PubMed
  94. Cesana M, Broccali G, Imbimbo BP, Crema A. Effect of single doses of rufloxacin on the disposition of theophylline and caffeine after single administration. Int J Clin Pharmacol Ther Toxicol 1991:29:133-8.
  95. Broughton LJ, Rogers HJ. Decreased systemic clearance of caffeine due to cimetidine. Br J Clin Pharmacol 1981;12:155-9. PubMed
  96. Kot M, Daniel WA. Caffeine as a marker substrate for testing cytochrome P450 activity in human and rat. Pharmacol Rep 2008;60:789-97.
  97. Kjaerstad MB, Nielsen F, Nohr-Jensen L, et al. Systemic uptake of miconazole during vaginal suppository use and effect on CYP1A2 and CYP3A4 associated enzyme activities in women. Eur J Clin Pharmacol 2010;66:1189-97. PubMed
  98. Goh BC, Reddy NJ, Dandamudi UB, et al. An evaluation of the drug interaction potential of pazopanib, an oral vascular endothelial growth factor receptor tyrosine kinase inhibitor, using a modified Cooperstown 5+1 cocktail in patients with advanced solid t
  99. Chen Y, Kang Z, Yan J, et al. Liu wei di huang wan, a well-known traditional Chinese medicine induces CYP1A2 while suppressing CYP2A6 and N-acetyltransferase 2 acivities in man. J Ethnopharmacol 2010;132:213-8.
  100. Suzuki S, Murayama Y, Sugiyama E, et al. Estimating pediatric doses of drugs metabolized by cytochrome P450 (CYP) isozymes, based on physiological liver development and serum protein levels. Yakugaku Zasshi 2010;130:613-20. PubMed
  101. Chien CF, Wu YT, Lee WC, et al. Herb-drug interaction of Andrographis paniculata extract and andrographolide on the pharmacokinetics of theophylline in rats. Chem Biol Interact 2010;184:458-65. PubMed
  102. Mills BM, Zaya MJ, Walters RR, et al. Current cytochrome P450 phenotyping methods applied to metabolic drug -drug interaction prediction in dogs. Drug Metab Dispos 2010;38:396-404. PubMed
  103. Turpault S, Brian W, Van Horn R, et al. Pharmacokinetic assessment of a five-probe cocktail for CYPs 1A2, 2C9, 2C19, 2D6, and 3A. Br J Clin Pharmacol 2009;68:928-35. PubMed
  104. Filimonova AA, Ziganshina LE, Ziganshin AU, Chichirov AA. On the possibility of patient phenotyping on the basis of cytochrome p-450 1A2 isoenzyme activity using caffeine as the test substrate. Eksp Klin Farmakol 2009;72:61-5.
  105. Jenkins J, Williams D, Deng Y, et al. Eltrombopag, an oral thrombopoietin receptor agonist, has no impact on the pharmacokinetic profile of probe drugs for cytochrome P450 isoenzymes CYP3A4, CYP1A2, CYP2C9 and CYP2C19 in healthy men: a cocktail analysis.
  106. Smits P, Straatman C, Pijpers E, Thien T. Dose-dependent inhibition of the hemodynamic response to dipyridamole by caffeine. Clin Pharmacol Ther 1991;50:529-37. PubMed
  107. Zelenitsky SA, Norman A, Nix DE. The effects of fluconazole on the pharmacokinetics of caffeine in young and elderly subjects. J Infect Dis Pharmacother 1995;1:1-11.
  108. Joeres R, Richter E. Mexiletine and caffeine elimination. N Engl J Med 1987;317:117. PubMed
  109. Jonkman JH, Sollie FA, Sauter R, Steinijans VW. The influence of caffeine on the steady-state pharmacokinetics of theophylline. Clin Pharmacol Ther 1991;49:248-55. PubMed
  110. Weathersbee PS, Olsen LK, Lodge JR. Caffeine and pregnancy. A retrospective survey. Postgrad Med 1977;62:64-9. PubMed
  111. Fortier I, Marcoux S, Beaulac-Baillargeon L. Relation of caffeine intake during pregnancy to intrauterine growth retardation and preterm birth. Am J Epidemiol 1993;137:931-40. PubMed
  112. Woodward, M. and Tunstall-Pedoe, H. Coffee and tea consumption in the Scottish Heart Health Study follow up: conflicting relations with coronary risk factors, coronary disease, and all cause mortality. J.Epidemiol.Community Health 1999;53(8):481-487. PubMed
  113. Steptoe, A., Gibson, E. L., Vuononvirta, R., Hamer, M., Wardle, J., Rycroft, J. A., Martin, J. F., and Erusalimsky, J. D. The effects of chronic tea intake on platelet activation and inflammation: a double-blind placebo controlled trial. Atherosclerosis PubMed
  114. Heilbrun, L. K., Nomura, A., and Stemmermann, G. N. Black tea consumption and cancer risk: a prospective study. Br.J.Cancer 1986;54(4):677-683. PubMed
  115. Kinlen, L. J. and McPherson, K. Pancreas cancer and coffee and tea consumption: a case-control study. Br.J.Cancer 1984;49(1):93-96. PubMed
  116. Smits, P., Temme, L., and Thien, T. The cardiovascular interaction between caffeine and nicotine in humans. Clin Pharmacol Ther 1993;54(2):194-204. PubMed
  117. Cnattingius, S., Signorello, L. B., Anneren, G., Clausson, B., Ekbom, A., Ljunger, E., Blot, W. J., McLaughlin, J. K., Petersson, G., Rane, A., and Granath, F. Caffeine intake and the risk of first-trimester spontaneous abortion. N.Engl.J.Med. 12-21-2000 PubMed
  118. Clausson, B., Granath, F., Ekbom, A., Lundgren, S., Nordmark, A., Signorello, L. B., and Cnattingius, S. Effect of caffeine exposure during pregnancy on birth weight and gestational age. Am.J.Epidemiol. 3-1-2002;155(5):429-436. DOI
  119. MacKenzie, T., Comi, R., Sluss, P., Keisari, R., Manwar, S., Kim, J., Larson, R., and Baron, J. A. Metabolic and hormonal effects of caffeine: randomized, double-blind, placebo-controlled crossover trial. Metabolism 2007;56(12):1694-1698. PubMed
  120. Barr, H. M. and Streissguth, A. P. Caffeine use during pregnancy and child outcome: a 7-year prospective study. Neurotoxicol.Teratol. 1991;13(4):441-448. PubMed
  121. Moisey, L. L., Robinson, L. E., and Graham, T. E. Consumption of caffeinated coffee and a high carbohydrate meal affects postprandial metabolism of a subsequent oral glucose tolerance test in young, healthy males. Br.J Nutr. 2010;103(6):833-841. PubMed
  122. Fenster, L., Eskenazi, B., Windham, G. C., and Swan, S. H. Caffeine consumption during pregnancy and fetal growth. Am.J.Public Health 1991;81(4):458-461. PubMed
  123. Simmonds, M. J., Minahan, C. L., and Sabapathy, S. Caffeine improves supramaximal cycling but not the rate of anaerobic energy release. Eur.J Appl Physiol 2010;109(2):287-295. PubMed
  124. Buscemi, S., Verga, S., Batsis, J. A., Donatelli, M., Tranchina, M. R., Belmonte, S., Mattina, A., Re, A., and Cerasola, G. Acute effects of coffee on endothelial function in healthy subjects. Eur.J Clin Nutr. 2010;64(5):483-489. PubMed
  125. Rigato, I., Blarasin, L., and Kette, F. Severe hypokalemia in 2 young bicycle riders due to massive caffeine intake. Clin J Sport Med. 2010;20(2):128-130. PubMed
  126. Banko, L. T., Haq, S. A., Rainaldi, D. A., Klem, I., Siegler, J., Fogel, J., Sacchi, T. J., and Heitner, J. F. Incidence of caffeine in serum of patients undergoing dipyridamole myocardial perfusion stress test by an intensive versus routine caffeine his
  127. Ernest, D., Chia, M., and Corallo, C. E. Profound hypokalaemia due to Nurofen Plus and Red Bull misuse. Crit Care Resusc. 2010;12(2):109-110. DOI
  128. Fenster, L., Eskenazi, B., Windham, G. C., and Swan, S. H. Caffeine consumption during pregnancy and spontaneous abortion. Epidemiology 1991;2(3):168-174. PubMed
  129. Clausen, T. Hormonal and pharmacological modification of plasma potassium homeostasis. Fundam.Clin Pharmacol 2010;24(5):595-605. PubMed
  130. Perera, V., Gross, A. S., and McLachlan, A. J. Caffeine and paraxanthine HPLC assay for CYP1A2 phenotype assessment using saliva and plasma. Biomed.Chromatogr. 2010;24(10):1136-1144. PubMed
  131. Orozco-Gregorio, H., Mota-Rojas, D., Bonilla-Jaime, H., Trujillo-Ortega, M. E., Becerril-Herrera, M., Hernandez-Gonzalez, R., and Villanueva-Garcia, D. Effects of administration of caffeine on metabolic variables in neonatal pigs with peripartum asphyxia PubMed
  132. Smits, P., Lenders, J. W., and Thien, T. Caffeine and theophylline attenuate adenosine-induced vasodilation in humans. Clin.Pharmacol.Ther. 1990;48(4):410-418. PubMed
  133. Caan, B. J. and Goldhaber, M. K. Caffeinated beverages and low birthweight: a case-control study. Am.J.Public Health 1989;79(9):1299-1300. PubMed
  134. Martin, T. R. and Bracken, M. B. The association between low birth weight and caffeine consumption during pregnancy. Am.J.Epidemiol. 1987;126(5):813-821. PubMed
  135. Srisuphan, W. and Bracken, M. B. Caffeine consumption during pregnancy and association with late spontaneous abortion. Am.J Obstet.Gynecol. 1986;154(1):14-20. PubMed
  136. Dlugosz, L., Belanger, K., Hellenbrand, K., Holford, T. R., Leaderer, B., and Bracken, M. B. Maternal caffeine consumption and spontaneous abortion: a prospective cohort study. Epidemiology 1996;7(3):250-255. PubMed
  137. Jeppesen, U., Loft, S., Poulsen, H. E., and Brsen, K. A fluvoxamine-caffeine interaction study. Pharmacogenetics 1996;6(3):213-222. PubMed
  138. Cook, D. G., Peacock, J. L., Feyerabend, C., Carey, I. M., Jarvis, M. J., Anderson, H. R., and Bland, J. M. Relation of caffeine intake and blood caffeine concentrations during pregnancy to fetal growth: prospective population based study. BMJ 11-30-1996 PubMed
  139. Izzo, A. A. and Ernst, E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs 2009;69(13):1777-1798. PubMed
  140. Alemdaroglu, N. C., Dietz, U., Wolffram, S., Spahn-Langguth, H., and Langguth, P. Influence of green and black tea on folic acid pharmacokinetics in healthy volunteers: potential risk of diminished folic acid bioavailability. Biopharm.Drug Dispos. 2008;2 PubMed
  141. Smits, P., Corstens, F. H., Aengevaeren, W. R., Wackers, F. J., and Thien, T. False-negative dipyridamole-thallium-201 myocardial imaging after caffeine infusion. J Nucl.Med. 1991;32(8):1538-1541. DOI
  142. van der Hoeven N, Visser I, Schene A, van den Born BJ. Severe hypertension related to caffeinated coffee and tranylcypromine: a case report. Ann Intern Med. 2014 May 6;160(9):657-8. doi: 10.7326/L14-5009-8. No abstract available. PubMed
  143. Bahorun T, Luximon-Ramma A, Neergheen-Bhujun VS, Gunness TK, Googoolye K, Auger C, Crozier A, Aruoma OI. The effect of black tea on risk factors of cardiovascular disease in a normal population. Prev Med. 2012 ;54 Suppl:S98-102. PubMed
  144. Wikoff D, Welsh BT, Henderson R, et al. Systematic review of the potential adverse effects of caffeine consumption in healthy adults, pregnant women, adolescents, and children. Food Chem Toxicol 2017;109:585-648. PubMed
  145. Lin S, Xu G, Chen Z, Liu X, Li J, Ma L, Wang X. Tea drinking and the risk of esophageal cancer: focus on tea type and drinking temperature. Eur J Cancer Prev. 2020. doi: 10.1097/CEJ.0000000000000568. PubMed
  146. Kondo A, Narumi K, Okuhara K, et al. Black tea extract and theaflavin derivatives affect the pharmacokinetics of rosuvastatin by modulating organic anion transporting polypeptide (OATP) 2B1 activity. Biopharm Drug Dispos. 2019;40(8):302-306. PubMed
  147. Zheng KH, Zhu K, Wactawski-Wende J, et al. Caffeine intake from coffee and tea and invasive breast cancer incidence among postmenopausal women in the Women's Health Initiative. Int J Cancer 2021;149(12):2032-2044. PubMed
  148. Wang S, Li X, Yang Y, et al. Does coffee, tea and caffeine consumption reduce the risk of incident breast cancer? A systematic review and network meta-analysis. Public Health Nutr 2021;24(18):6377-6389. PubMed
  149. Alshabi AM, Alkahtani SA, Shaikh IA, Habeeb MS. Caffeine modulates pharmacokinetic and pharmacodynamic profiles of pioglitazone in diabetic rats: Impact on therapeutics. Saudi Med J 2021;42(2):151-160. PubMed
  150. Gleason JL, Sundaram R, Mitro SD, et al. Association of maternal caffeine consumption during pregnancy with child growth. JAMA Netw Open. 2022;5(10):e2239609. PubMed

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