Drug & supplement interaction

Acetyl-l-carnitine + Aspirin, Codeine Phosphate, Phenobarbital

Aspirin, Codeine Phosphate, Phenobarbital brand name: Phenaphen.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Acetyl-l-carnitine and Aspirin, Codeine Phosphate, Phenobarbital in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Acetyl-l-carnitine and Aspirin, Codeine Phosphate, Phenobarbital

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Aspirin, Codeine Phosphate, Phenobarbital and Acetyl-l-carnitine in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Acetyl-l-carnitine safety at a glance

Acetyl-l-carnitine overall Use caution Generally well tolerated short-term, but long-term safety is not fully established.
Pregnancy Avoid There is not enough reliable safety information, so it is best avoided unless your doctor advises otherwise.
Breastfeeding Avoid Safety while breastfeeding is unknown, so avoiding it is the safer choice.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Aspirin, Codeine Phosphate, Phenobarbital and Acetyl-l-carnitine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Aspirin, Codeine Phosphate, Phenobarbital

Interactions in our licensed database are recorded against drug classes, not just single drug names. Aspirin, Codeine Phosphate, Phenobarbital is filed under 19 classifications — including codeine, cytochrome p450 2b6 (cyp2b6) substrates, cytochrome p450 2c9 (cyp2c9) inducers. Acetyl-l-carnitine has documented interactions with 4 drug classes — the most serious being acenocoumarol (sintrom) (moderate), serotonergic drugs (moderate) and thyroid hormone (moderate) — and none of Aspirin, Codeine Phosphate, Phenobarbital’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Acetyl-l-carnitine Does Interact With Other Medications

Acetyl-l-carnitine has 203 moderate known drug interactions in our database — Aspirin, Codeine Phosphate, Phenobarbital isn’t one of them. If you take anything else, check it against the full list below.

Moderate 203 No known interaction 2,627 (incl. Aspirin, Codeine Phosphate, Phenobarbital)
Taking anything else?

Check Another of Your Medications Against Acetyl-l-carnitine

Covers the 2,830 medications we’ve checked against Acetyl-l-carnitine. Pick one to open its full report.

What to actually watch for

What Acetyl-l-carnitine Itself Has Been Linked To

This is not an interaction — nothing below involves Aspirin, Codeine Phosphate, Phenobarbital. It is the side-effect record for Acetyl-l-carnitine on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Acetyl-l-carnitine, this list is the first place to look. 3 entries are worth acting on rather than waiting out — marked below.

  • Mania or an unusually elevated mood Worth acting on Additional detail

    “Orally, acetyl-L-carnitine may cause agitation (restlessness and motor overactivity). Side effects reported in people with Alzheimer disease include psychiatric disturbances such as depression, mania, confusion and aggression, but it is not clear whether these are due to acetyl-L-carnitine or the condition itself.”

    Acetyl-l-carnitine · Natural Medicines adverse-effect record, reported in alzheimer disease.

    6 sources cited
    1. 1596. Spagnoli A, Lucca U, Menasce G, et al. Long-term acetyl-L-carnitine treatment in Alzheimer's Disease. Neurology 1991;41:1726-32. PubMed
    2. 1599. Rai G, Wright G, Scott L, et al. Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer's dementia. Curr Med Res Opin 1990;11:638-47. PubMed
    3. 12743. De Grandis D, Minardi C. Acetyl-L-carnitine (levacecarnine) in the treatment of diabetic neuropathy. A long-term, randomised, double-blind, placebo-controlled study. Drugs R D 2002;3:223-31. PubMed
    4. 13007. Sima AAF, Calvani M, Mehra M, et al. Acetyl-L-carnitine improves pain, nerve regeneration, and vibratory perception in patients with chronic diabetic neuropathy: An analysis of two randomized, placebo-controlled trials. Diabetes Care 2005;28:89-94.
    5. 1594. Thal LJ, Carta A, Clarke WR, et al. A 1-year multicenter placebo-controlled study of acetyl-L-carnitine in patients with Alzheimer's Disease. Neurology 1996;47:705-11. PubMed
    6. 1595. Sano M, Bell K, Cote L, et al. Double-blind parallel design pilot study of acetyl levocarnitine in patients with Alzheimer's Disease. Arch Neurol 1992;49:1137-41. PubMed

    “Orally, acetyl-L-carnitine may cause headache and insomnia. In one clinical trial, two patients with antiretroviral toxic neuropathy reported paresthesia, pain, and neuropathy after taking acetyl-L-carnitine 1000 mg daily. A case of mania has been reported for a patient with bipolar I disorder currently in remission.”

    Acetyl-l-carnitine · Natural Medicines adverse-effect record, reported in bipolar disorder.

    5 sources cited
    1. 90760. Ledinek AH, Sajko MC, Rot U. Evaluating the effects of amantadin, modafinil and acetyl-L-carnitine on fatigue in multiple sclerosis--result of a pilot randomized, blind study. Clin Neurol Neurosurg. 2013 Dec;115 Suppl 1:S86-9. PubMed
    2. 90767. Martinotti G, Andreoli S, Reina D, Di Nicola M, Ortolani I, Tedeschi D, Fanella F, Pozzi G, Iannoni E, D'Iddio S, Prof LJ. Acetyl-l-Carnitine in the treatment of anhedonia, melancholic and negative symptoms in alcohol dependent subjects. Prog Neuropsychop PubMed
    3. 95063. Bruno A, Pandolfo G, Crucitti M, Lorusso S, Zoccali RA, Muscatello MR. Acetyl-L-Carnitine Augmentation of Clozapine in Partial-Responder Schizophrenia: A 12-Week, Open-Label Uncontrolled Preliminary Study. Clin Neuropharmacol. 2016;39(6):277-80. PubMed
    4. 58342. Youle, M. and Osio, M. A double-blind, parallel-group, placebo-controlled, multicentre study of acetyl L-carnitine in the symptomatic treatment of antiretroviral toxic neuropathy in patients with HIV-1 infection. HIV.Med. 2007;8(4):241-250.
    5. 95062. Goodison G, Overeem K, de Monte V, Siskind D. Mania associated with self-prescribed acetyl-l-carnitine in a man with bipolar I disorder. Australas Psychiatry. 2017;25(1):13-4.
  • Confusion / Low mood Worth acting on Additional detail

    Recorded for Acetyl-l-carnitine in the same Natural Medicines adverse-effect record shown under Mania or an unusually elevated mood above.

  • Raised blood pressure Worth acting on Additional detail

    “Orally, one patient in a pharmacokinetic study reported high blood pressure 8 hoursafter taking acetyl-L-carnitine 500 mg; however, it is unclear if this was due to acetyl-L-carnitine or another factor.”

    Acetyl-l-carnitine · Natural Medicines adverse-effect record, reported in hypertension.

    1 source cited
    1. 95061. Baek SM, Zheng R, Seo EJ, Hwang DY, Kim BH. Pharmacokinetic comparisons of two acetyl-L-carnitine formulations in healthy Korean volunteers. Int J Clin Pharmacol Ther. 2015;53(11):980-6. PubMed
  • Mood changes or irritability / Numbness or tingling Additional detail

    Recorded for Acetyl-l-carnitine in the same Natural Medicines adverse-effect record shown under Mania or an unusually elevated mood above.

  • Bloating or gas Additional detail

    “Orally, acetyl-L-carnitine may cause nausea, vomiting, diarrhea, constipation, hiccups, abdominal distension and gastrointestinal upset or pain. However, gastrointestinal symptoms do not usually occur more often in patients receiving acetyl-L-carnitine than in patients receiving placebo. Acetyl-L-carnitine may also cause dry mouth and anorexia.”

    Acetyl-l-carnitine · Natural Medicines adverse-effect record, reported in anorexia.

    2 sources cited
    1. 58342. Youle, M. and Osio, M. A double-blind, parallel-group, placebo-controlled, multicentre study of acetyl L-carnitine in the symptomatic treatment of antiretroviral toxic neuropathy in patients with HIV-1 infection. HIV.Med. 2007;8(4):241-250.
    2. 90441. Brennan BP, Jensen JE, Hudson JI, Coit CE, Beaulieu A, Pope HG Jr, Renshaw PF, Cohen BM. A placebo-controlled trial of acetyl-L-carnitine and a-lipoic acid in the treatment of bipolar depression. J Clin Psychopharmacol. 2013 Oct;33(5):627-35.
  • Dry mouth / Reduced appetite Additional detail

    “Orally, acetyl-L-carnitine is generally well tolerated.

    Most Common Adverse Effects:

    Orally: Agitation, dry mouth, headache, insomnia, and reduced appetite. A metabolite of acetyl-L-carnitine has been reported to cause a fishy odor of the urine, breath, and sweat.”

    Acetyl-l-carnitine · Natural Medicines adverse-effect record, reported in cluster headache.

  • Anxiety or restlessness Additional detail

    Recorded for Acetyl-l-carnitine in the same Natural Medicines adverse-effect record shown under Dry mouth / Reduced appetite above.

Showing the 10 most notable of 17 recorded effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

Everything above comes from the Natural Medicines adverse-effect record for Acetyl-l-carnitine — expand a row for the licensed statement it rests on. We haven’t matched Aspirin, Codeine Phosphate, Phenobarbital to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Aspirin, Codeine Phosphate, Phenobarbital.

Worth knowing

No Interaction — But Aspirin, Codeine Phosphate, Phenobarbital May Lower Your Acetyl-l-carnitine Levels

These two do not interact. The relationship runs the other way: the licensed record lists Aspirin, Codeine Phosphate, Phenobarbital as associated with lower Acetyl-l-carnitine levels — rated “Insignificant Depletion”.

Theoretically, acetyl-L-carnitine levels may be reduced in patients taking phenobarbital. Data on the effect of phenobarbital on blood levels of carnitines are conflicting. Some studies have found reduced L-carnitine levels in some patients taking phenobarbital. However, other studies have found no significant effect. Routine L-carnitine or acetyl-L-carnitine supplementation does not seem to be necessary.

ACETYL-L-CARNITINE — Insignificant Depletion

See every medication linked to lower Acetyl-l-carnitine levels · See the full Aspirin, Codeine Phosphate, Phenobarbital nutrient report

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

Everything else you take

See Every Supplement That Interacts With Aspirin, Codeine Phosphate, Phenobarbital

This page covers Acetyl-l-carnitine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Aspirin, Codeine Phosphate, Phenobarbital page lists 352 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: 1,4-butanediol (major), Activated Charcoal (major), Asarabacca (major), Beer (major) and Danshen (major).

By severity: 12 major · 304 moderate · 36 minor.

From our pharmacist’s overview on the Aspirin, Codeine Phosphate, Phenobarbital page

“Alcohol is the entry I would flag first with Phenaphen (aspirin, codeine phosphate, phenobarbital): beer or wine layered onto codeine and phenobarbital can deepen sedation and, at worst, slow breathing. This medication deserves real caution with supplements.”

Reviewed by 2 · Jul 18, 2026

Open the Aspirin, Codeine Phosphate, Phenobarbital interaction page

One more smart check

Taking Acetyl-l-carnitine as Part of a Dietary Supplement Product? Check It for Interactions

We hold 405 real supplement products containing Acetyl-l-carnitine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Acetyl-l-carnitine. Even though Acetyl-l-carnitine itself has no known interaction with Aspirin, Codeine Phosphate, Phenobarbital, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Acetyl-l-carnitine and Aspirin, Codeine Phosphate, Phenobarbital Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Acetyl-l-carnitine
Top 10%

#96 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Aspirin, Codeine Phosphate, Phenobarbital
Top 10%

#206 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Acetyl-l-carnitine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Acetyl-l-carnitine and Aspirin, Codeine Phosphate, Phenobarbital records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Acetyl-l-carnitine

What is Acetyl-l-carnitine?

Acetyl-l-carnitine
  • Memory and cognitive support
  • Nerve pain (neuropathy)
  • Energy and fatigue
  • Age-related decline
  • Male fertility
  • Mood support

Acetyl-L-carnitine is a form of the amino acid carnitine that the body uses to help produce energy in cells. It is most studied for nerve pain and memory-related conditions, though the evidence is mixed and often limited. It is generally well tolerated for short-term use, but you should talk with your pharmacist or doctor before starting it.

Not applicable (a naturally occurring compound made in the body) · Capsules, tablets, powder, and liquid

An interaction check asks whether these two react with each other — it does not ask whether Acetyl-l-carnitine is a good idea for someone in your situation. Here is what our Acetyl-l-carnitine record says about it on its own.

Acetyl-l-carnitine: dosing

There is no single official dose of Acetyl-L-carnitine for any condition. Taking it with food may help reduce stomach upset. Do not assume that taking more will work better, as higher amounts can increase the chance of side effects.

From our Acetyl-l-carnitine monograph — the full record covers uses, side effects and every documented interaction.

Read the full Acetyl-l-carnitine monograph & all interactions
Keep checking

Other Drugs & Acetyl-l-carnitine

Browse every other medication we’ve checked against Acetyl-l-carnitine — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
203Moderate
0Minor
2,626No known interaction
203 Moderate 2,626 No interaction
Moderate

203 interactions

Showing 60 of 203 moderate interactions — see all 203 on the Acetyl-l-carnitine page.

No interaction 2,626 drugs checked — show the list

We also checked Acetyl-l-carnitine against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,626 medications checked with no known interaction — see the full Acetyl-l-carnitine list.

See the full Acetyl-l-carnitine interactions page
See every supplement checked against Aspirin, Codeine Phosphate, Phenobarbital, ranked by severity
Evidence & sources

Acetyl-l-carnitine References

The 22 references that drive our Acetyl-l-carnitine monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Thal LJ, Carta A, Clarke WR, et al. A 1-year multicenter placebo-controlled study of acetyl-L-carnitine in patients with Alzheimer's Disease. Neurology 1996;47:705-11. PubMed
  2. Sano M, Bell K, Cote L, et al. Double-blind parallel design pilot study of acetyl levocarnitine in patients with Alzheimer's Disease. Arch Neurol 1992;49:1137-41. PubMed
  3. Spagnoli A, Lucca U, Menasce G, et al. Long-term acetyl-L-carnitine treatment in Alzheimer's Disease. Neurology 1991;41:1726-32. PubMed
  4. Brooks JO 3rd, Yesavage JA, Carta A, Bravi D. Acetyl L-carnitine slows decline in younger patients with Alzheimer's disease: a reanalysis of a double-blind, placebo-controlled study using the trilinear approach. Int Psychoger 1998;10:193-203. PubMed
  5. Pettegrew JW, Klunk WE, Panchalingam K, et al. Clinical and neurochemical effects of acetyl-L-carnitine in Alzheimer's disease. Neurobiol Aging 1995;16:1-4. PubMed
  6. Rai G, Wright G, Scott L, et al. Double-blind, placebo controlled study of acetyl-l-carnitine in patients with Alzheimer's dementia. Curr Med Res Opin 1990;11:638-47. PubMed
  7. Benvenga S, Ruggeri RM, Russo A, et al. Usefulness of L-carnitine, a naturally occurring peripheral antagonist of thyroid hormone action, in iatrogenic hyperthyroidism: a randomized, double-blind, placebo-controlled clinical trial. J Clin Endocrinol Meta
  8. Montgomery SA, Thal LJ, Amrein R. Meta-analysis of double blind randomized controlled clinical trials of acetyl-L-carnitine versus placebo in the treatment of mild cognitive impairment and mild Alzheimer's disease. Int Clin Psychopharmacol 2003;18:61-71.. PubMed
  9. Martinez E, Domingo P, Roca-Cusachs A. Potentiation of acenocoumarol action by L-carnitine. J Intern Med 1993;233:94.
  10. Hudson S, Tabet N. Acetyl-L-carnitine for dementia. Cochrane Database Syst Rev 2003;2:CD003158.. PubMed
  11. Bachmann HU, Hoffmann A. Interaction of food supplement L-carnitine with oral anticoagulant acenocoumarol. Swiss Med Wkly 2004;134:385. PubMed
  12. De Grandis D, Minardi C. Acetyl-L-carnitine (levacecarnine) in the treatment of diabetic neuropathy. A long-term, randomised, double-blind, placebo-controlled study. Drugs R D 2002;3:223-31. PubMed
  13. 12761 Benvenga S, Amato A, Calvani M, Trimarchi F. Effects of carnitine on thyroid hormone action. Ann N Y Acad Sci 2004;1033:158-67. PubMed
  14. Sima AAF, Calvani M, Mehra M, et al. Acetyl-L-carnitine improves pain, nerve regeneration, and vibratory perception in patients with chronic diabetic neuropathy: An analysis of two randomized, placebo-controlled trials. Diabetes Care 2005;28:89-94.
  15. Youle, M. and Osio, M. A double-blind, parallel-group, placebo-controlled, multicentre study of acetyl L-carnitine in the symptomatic treatment of antiretroviral toxic neuropathy in patients with HIV-1 infection. HIV.Med. 2007;8(4):241-250.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Acetyl-l-carnitine and Aspirin, Codeine Phosphate, Phenobarbital Together: Common Questions

Is it safe to take Acetyl-l-carnitine with Aspirin, Codeine Phosphate, Phenobarbital?
We do not list a known interaction between Acetyl-l-carnitine and Aspirin, Codeine Phosphate, Phenobarbital. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Can Aspirin, Codeine Phosphate, Phenobarbital lower my Acetyl-l-carnitine levels?
Natural Medicines records Aspirin, Codeine Phosphate, Phenobarbital as a medicine that can deplete Acetyl-l-carnitine. That is the opposite direction to an interaction — it is a reason some people are told to take a supplement, not a reason to avoid one. Do not start one on the strength of this page; ask your pharmacist or doctor whether it applies to you.
How was the Acetyl-l-carnitine and Aspirin, Codeine Phosphate, Phenobarbital combination checked?
Interactions in our licensed database are recorded against drug classes. Aspirin, Codeine Phosphate, Phenobarbital is filed under 19 classifications, and Acetyl-l-carnitine has documented interactions with 4 drug classes — none of Aspirin, Codeine Phosphate, Phenobarbital's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Acetyl-l-carnitine interact with any other medications?
Yes. Acetyl-l-carnitine has 203 documented drug interactions in our database — Aspirin, Codeine Phosphate, Phenobarbital is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Aspirin, Codeine Phosphate, Phenobarbital interact with any supplements?
Yes. Aspirin, Codeine Phosphate, Phenobarbital has documented interactions with 352 supplements in our database — Acetyl-l-carnitine is not one of them. The Aspirin, Codeine Phosphate, Phenobarbital interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Acetyl-l-carnitine monograph Uses, safety profile, and every drug interaction in one place Aspirin, Codeine Phosphate, Phenobarbital supplement interactions Every supplement checked against Aspirin, Codeine Phosphate, Phenobarbital, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 22 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.