Theophylline & Nutrient Depletion
Also searched as T-Phyl, Duraphyl, Aerolate JR. What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.
Theophylline has been associated with depletion of POTASSIUM and VITAMIN B6. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Theophylline long-term, worth raising with your pharmacist or healthcare provider.
Take more than one medication? Open the checker with Theophylline pre-loaded and add the rest to see overlapping nutrient signals.
Reported nutrient depletions with Theophylline
Each record below is shown as published in our licensed clinical database, with its evidence rating and citations. Expand a section for food sources and talking points.
POTASSIUM
Moderate DepletionMETHYLXANTHINES
Methylxanthines like theophylline can reduce serum potassium levels, possibly by increasing intracellular uptake of potassium. Hypokalemia is most likely to occur after acute overdose of these drugs. However, reduced potassium levels can occur with therapeutic doses, and the incidence and degree of hypokalemia increases with increasing serum theophylline levels. Monitor potassium levels in people with other risk factors for hypokalemia. For information on foods that are rich in potassium, see our chart.
Potassium is a mineral your heart, muscles, and nerves depend on to work properly. Theophylline appears to push potassium from the bloodstream into your body's cells, which can nudge blood potassium levels lower, and that effect tends to be more noticeable at higher drug levels. This is a moderate concern, not just a theoretical one, so if you take theophylline regularly, it is worth asking your doctor or pharmacist whether your potassium levels should be checked, especially if you have other reasons your potassium might already run low.
What Potassium does & food sources
Potassium keeps nerve signals, muscle contractions, and heart rhythm working normally.
Common food sources:
- Bananas and citrus fruits
- Potatoes and sweet potatoes
- Beans and lentils
- Tomatoes and leafy greens
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Potassium is routinely checked with basic blood work. If you take a medication associated with potassium loss (like some diuretics), ask your provider how often your electrolytes should be monitored.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Do not start potassium supplements on your own. Both low and high potassium can affect heart rhythm, and several common medications (ACE inhibitors, ARBs, potassium-sparing diuretics) raise potassium.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Potassium supplementation can be dangerous in kidney disease or alongside potassium-raising medications — this is a decision for your prescriber, guided by lab results.
Learn more about this nutrient: Potassium — uses, safety & interactions
References (5)
- Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
- Crane J, Burgess CD, Graham AN, Maling TJB. Hypokalemic and electrocardiographic effects of aminophylline and salbutamol in obstructive airways disease. NZ Med J 1987;100:309-11. DOI
- Zantvoort FA, Derkx FHM, Boomsma F, et al. Theophylline and serum electrolytes (letter). Ann Int Med 1986;104:134-5. PubMed
- Braat MCP, Jonkers RE, Bel EH, Van Boxtel CJ. Quantification of theophylline-induced eosinopenia and hypokalamia in healthy volunteers. Clin Pharmacokinet 1992;22:231-7..
- Flack JM, Ryder KW, Strickland D, Whang R. Metabolic correlates of theophylline therapy: a concentration-related phenomenon. Ann Pharmacother 1994;28:175-9.. PubMed
VITAMIN B6
Moderate DepletionTHEOPHYLLINE
Theophylline inhibits pyridoxal kinase, which catalyzes phosphorylation of vitamin B6 to its active form, pyridoxal-5'-phosphate. People treated with theophylline tend to have reduced plasma pyridoxal-5'-phosphate levels. The clinical significance of this is not clear, although it is suggested that vitamin B6 deficiency contributes to neurological and CNS side effects of theophylline, including seizures. Vitamin B6 (pyridoxine) supplements of 10-300 mg daily have been tried in people taking theophylline, but results are conflicting. Although plasma levels are sometimes returned to normal, it's not clear if there is any clinical benefit.
Vitamin B6 is something your body needs to keep nerves working properly and to help make important brain chemicals. Theophylline can actually block an enzyme that converts B6 into the active form your body can use, so blood levels of that active form tend to run lower in people taking this medication. This is rated as a moderate depletion, meaning it is real enough that some long-term users may benefit from a supplement, though the picture is still a bit murky since studies on whether supplementing actually helps have had mixed results. If you have been on theophylline for a while, it is worth bringing this up with your pharmacist or doctor to see if monitoring or a supplement makes sense for you.
What Vitamin B6 does & food sources
Vitamin B6 is involved in protein metabolism, neurotransmitter production, and red blood cell formation.
Common food sources:
- Poultry and fish
- Potatoes and starchy vegetables
- Bananas
- Fortified cereals
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
With some medications (for example, isoniazid), B6 is intentionally co-prescribed — follow your prescriber's plan. Otherwise, ask whether testing or supplementation is appropriate if you have symptoms like numbness or tingling.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Paradoxically, long-term high-dose B6 can itself cause nerve symptoms — this is a nutrient where more is definitely not better.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Avoid high-dose B6 without medical guidance; sustained high intakes can cause neuropathy.
Learn more about this nutrient: Vitamin B6 — uses, safety & interactions
References (7)
- Delport R, Ubbink JB, Serfontein WJ, et al. Vitamin B6 nutritional status in asthma. The effect of theophylline therapy on plasma pyridoxal-5-phosphate and pyridoxal levels. Int J Vitam Nutr Res 1988;58:67-72.
- Sur S, Camara M, Buchmeier A, et al. Double-blind trial of pyridoxine (vitamin B6) in the treatment of steroid-dependent asthma. Ann Allergy 1993;70:147-52.
- Shimizu T, Maeda S, Mochizuki H, et al. Theophylline attenuates circulating vitamin B6 levels in children with asthma. Pharmacology 1994;49:392-7.
- Ubbink JB, Delport R, Becker PJ, Bissport S. Evidence of a theophylline-induced vitamin B6 deficiency caused by noncompetitive inhibition of pyridoxal kinase. J Lab Clin Med 1989;113:15-22..
- Delport R, Ubbink JB, Vermaak WJ, Becker PJ. Theophylline increases pyridoxal kinase activity independently from vitamin B6 nutritional status. Res Commun Chem Pathol Pharmacol 1993;79:325-33..
- Ubbink JB, Vermaak WJ, Delport R, et al. The relationship between vitamin B6 metabolism, asthma, and theophylline therapy. Ann N Y Acad Sci 1990;585:285-94.
- Bartel PR, Ubbink JB, Delport R, et al. Vitamin B6 supplementation and theophylline-related effects in humans. Am J Clin Nutr 1994;60:93-9..
This tool is educational and is not a substitute for professional medical advice. An association is not a diagnosis and does not mean a deficiency will occur. Always talk to your pharmacist or healthcare provider before starting, stopping, or changing any medication or supplement.
Disclaimer: This checker finds which nutrients might be depleted by prescription or over-the-counter medications. Each nutrient depletion issue is rated based on clinical significance. Use your own professional judgment prior to making clinical decisions.© 2026 Therapeutic Research Center Licensed records refresh weekly · last updated July 3, 2026.
More about Theophylline
What drug-induced nutrient depletion means
Some medications can, over time, lower the levels of certain vitamins, minerals, or other nutrients — through reduced absorption, increased loss, or changes in how the body uses them.
Association is not deficiency
An entry here means a depletion has been reported or studied — not that it happens to everyone, or that you are deficient. Dose, duration, diet, and your own health all matter.
Evidence varies by pair
Some drug–nutrient links (like metformin and vitamin B12) are well studied; others rest on limited or preliminary research. Each entry shows the evidence rating from our licensed clinical database.
When to ask about labs
If you take an associated medication long-term, ask your healthcare provider whether monitoring is appropriate for you. Not everyone needs testing — your provider can weigh your dose, duration, and symptoms.
Don't self-supplement blindly
Supplements are not risk-free: some can interact with medications, and some (like potassium or magnesium) can be risky with kidney disease. Talk to your pharmacist before adding anything.
Never stop a medication over this
These medications are prescribed for good reasons, and the benefit usually far outweighs a manageable nutrient consideration. Any change belongs in a conversation with your prescriber.
Food first, usually
For many nutrients, a varied diet covers the gap. Each entry lists common food sources; a supplement is a decision to make with your pharmacist or provider, not a default.
Theophylline & nutrients: FAQs
Does Theophylline deplete POTASSIUM?
Should I take a supplement because I take Theophylline?
Should I stop taking Theophylline?
Where does this information come from?
Questions about Theophylline and your nutrition?
Ask a licensed pharmacist — free, no appointment needed.
Sources & How We Checked
Nutrient depletion records for Theophylline are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for drug-induced nutrient depletions, supplements, and interactions — the basis for this page.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for medication overviews across the site.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.