Drug & supplement interaction

Acetyl-l-carnitine + nefazodone

nefazodone brand name: Serzone.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Acetyl-l-carnitine has a moderate interaction with nefazodone. Theoretically, acetyl-L-carnitine might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders, when taken with serotonergic drugs.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Acetyl-l-carnitine and nefazodone

Here is the interaction we found between these two, with the evidence behind it.

Moderate

SEROTONERGIC DRUGS

Why this applies to nefazodone

nefazodone falls under SEROTONERGIC DRUGS — the group Acetyl-l-carnitine interacts with.

Theoretically, acetyl-L-carnitine might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders, when taken with serotonergic drugs.
Animal research shows that acetyl-L-carnitine can increase levels of serotonin in the brain.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the gist with nefazodone (Serzone) and acetyl-L-carnitine. Nefazodone is an antidepressant that raises serotonin activity in your brain. In animal studies, acetyl-L-carnitine seems to nudge brain serotonin levels up too. Put them together and, in theory, you could be stacking two things that both push serotonin in the same direction.

When serotonin climbs too high, you can get what's called serotonin syndrome: agitation, sweating, a racing heart, tremor, or confusion. I want to be honest though, this is theoretical and based on lab and animal work, not real-world cases, so the actual risk looks low. Still, it's worth a quick chat with your pharmacist or doctor before adding the supplement, and don't change your nefazodone on your own.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Veronese N, Stubbs B, Solmi M, Ajnakina O, Carvalho AF, Maggi S. Acetyl-L-Carnitine Supplementation and the Treatment of Depressive Symptoms: A Systematic Review and Meta-Analysis. Psychosom Med. 2018;80(2):154-9. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Acetyl-l-carnitine Also Interacts With Other Medications

Acetyl-l-carnitine has 202 moderate known drug interactions in our database — the nefazodone one above is one of them. If you take anything else, check it against the full list below.

Moderate 202 No known interaction 2,628 (incl. nefazodone)
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.

Everything else you take

See Every Supplement That Interacts With nefazodone

This page covers Acetyl-l-carnitine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the nefazodone page lists 159 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Lithium (major), St. John's Wort (major) and 5-htp (moderate).

By severity: 4 major · 114 moderate · 41 minor.

From our pharmacist’s overview on the nefazodone page

“Nefazodone (Serzone) treats depression by working on serotonin, and it also strongly blocks a liver enzyme called CYP3A4, which is exactly why this list deserves your close attention. The largest group, 121 ingredients, are ones nefazodone can push to higher levels because it slows their breakdown.”

Reviewed by 2 · Jul 18, 2026

Open the nefazodone 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. Your product may carry other ingredients that interact with nefazodone too, on top of Acetyl-l-carnitine — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Acetyl-l-carnitine and nefazodone 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 nefazodone
Steady interest

#2,613 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.

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.

Read the full Acetyl-l-carnitine monograph & all interactions
Medication

About Nefazodone

What Is Nefazodone Used For?

Brand name: Serzone

Nefazodone Hydrochloride tablets are approved to treat depression, specifically major depressive disorder (MDD). Clinical trials established its effectiveness over 6 to 8 weeks in outpatients and 6 weeks in hospitalized patients with depression.

Nefazodone has also been shown to help prevent depression from coming back in patients who responded well to initial treatment. Because of a serious risk of liver failure, prescribers are advised to consider other antidepressants before turning to nefazodone.

See full Nefazodone drug information
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
202Moderate
0Minor
2,627No known interaction
202 Moderate 2,627 No interaction
Moderate

202 interactions

Showing 60 of 202 moderate interactions — see all 202 on the Acetyl-l-carnitine page.

No interaction 2,627 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 2,627 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 nefazodone, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

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

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Acetyl-l-carnitine monograph › Uses, safety, and every drug interaction in one place nefazodone supplement interactions › Every supplement checked against nefazodone, ranked by severity Nefazodone drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Acetyl-l-carnitine and nefazodone Together: Common Questions

Can you take Acetyl-l-carnitine with nefazodone?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Acetyl-l-carnitine and nefazodone interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About nefazodone and Acetyl-l-carnitine?

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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.