Huperzine A and medications.
Huperzine A is in the Distil supplement database, evidence Grade B. The page below lists every medication we have explicitly assessed it against.
Huperzine A is an alkaloid isolated from Chinese club moss, and it acts more like a drug than a nutrient. It inhibits acetylcholinesterase, the enzyme that breaks down acetylcholine, so brain levels of that signalling chemical rise. The Grade B evidence is strongest for memory and cognition in age-related decline and Alzheimer's disease, much of it from Chinese RCTs; a 2008 Cochrane meta-analysis found benefits but rated the evidence quality as insufficient for firm recommendations. Because the mechanism is pharmacological, cycling is needed, typically two to four weeks on and two weeks off, and that limits its use as a daily long-term supplement. The interaction angle is genuine, not theoretical. Combining it with prescription cholinesterase inhibitors such as donepezil, rivastigmine, or galantamine risks additive toxicity and is a hard exclusion. It opposes anticholinergic drugs and its cholinergic effects on heart rate mean any cardiac medication warrants caution. Treat it as a short-course cognitive tool, not a casual everyday capsule.
Below are the 17 documented pairs we have explicitly assessed for Huperzine A: 2 red and 15 amber. The pairs cluster around 3 mechanisms: Additive cholinergic effect, Additive bradycardia (slowed heart rate), and Cholinergic vs anticholinergic (opposing). Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not listed here is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by medication, and the missing-item form at the bottom of the page routes any uncatalogued medication into our next curation pass.
Documented interactions
Last reviewed 15 June 2026. Each interaction below is assessed against PubMed-indexed evidence.
Additive cholinergic effect
Red Does interact with Donepezil hydrochloride?
Huperzine A and donepezil both raise acetylcholine by blocking the same enzyme, so taking them together can stack their effects and lead to cholinergic side effects like a slow heart rate, nausea, diarrhoea, muscle cramps or, rarely, more serious problems. We treat this as a do-not-combine pair outside specialist supervision.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Red Does interact with Rivastigmine?
Huperzine A and rivastigmine both raise acetylcholine by blocking cholinesterase, so combining them can stack their effects and bring on cholinergic side effects such as a slow heart rate, nausea, diarrhoea and cramps. We treat this as a do-not-combine pair outside specialist supervision.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive bradycardia (slowed heart rate)
Amber Does interact with Atenolol?
Huperzine A can slow the heart a little through its effect on the nervous system, and beta-blockers like atenolol also slow the heart. Together they may add up and make your pulse too slow or cause dizziness or fainting. If you take a beta-blocker and huperzine A, it is worth telling your doctor and watching for a slow pulse or light-headedness. Older adults are more vulnerable to a slow pulse and to falls, so this is worth a check if it applies to you.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Cholinergic vs anticholinergic (opposing)
Amber Does interact with Amitriptyline?
Huperzine A raises acetylcholine, while amitriptyline has a strong anticholinergic effect that blocks it. The two can work against each other, and amitriptyline may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Chlorphenamine maleate?
Huperzine A raises acetylcholine, while chlorphenamine (a sedating antihistamine) has an anticholinergic effect that blocks it. The two can work against each other, so chlorphenamine may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Chlorpromazine?
Huperzine A raises acetylcholine, while chlorpromazine has a strong anticholinergic effect that blocks it. The two can work against each other, and chlorpromazine may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Clomipramine?
Huperzine A raises acetylcholine, while clomipramine has a strong anticholinergic effect that blocks it. The two can work against each other, and clomipramine may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Cyclizine hydrochloride?
Huperzine A raises acetylcholine, while cyclizine (an antihistamine used for nausea) has an anticholinergic effect that blocks it. The two can work against each other, so cyclizine may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Dosulepin?
Huperzine A raises acetylcholine, while dosulepin has an anticholinergic effect that blocks it. The two can work against each other, and dosulepin may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Imipramine?
Huperzine A raises acetylcholine, while imipramine has a strong anticholinergic effect that blocks it. The two can work against each other, and imipramine may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Lofepramine?
Huperzine A raises acetylcholine, while lofepramine has an anticholinergic effect that blocks it. The two can work against each other, and lofepramine may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Nortriptyline?
Huperzine A raises acetylcholine, while nortriptyline has an anticholinergic effect that blocks it. The two can work against each other, and nortriptyline may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Oxybutynin?
Huperzine A raises acetylcholine while oxybutynin blocks it, so each can work against the other. Huperzine A may make oxybutynin less effective for bladder symptoms, and oxybutynin may blunt any benefit from huperzine A. It is not dangerous, but the two are pulling in opposite directions, so it is worth a word with your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Procyclidine hydrochloride?
Huperzine A raises acetylcholine, while procyclidine is an anticholinergic that blocks it. The two pull in opposite directions, so each may reduce the other's effect. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Promethazine hydrochloride?
Huperzine A raises acetylcholine, while promethazine (a sedating antihistamine) has an anticholinergic effect that blocks it. The two can work against each other, so promethazine may blunt any benefit from huperzine A. It is worth mentioning the huperzine A to your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Solifenacin?
Huperzine A raises acetylcholine while solifenacin blocks it, so each can work against the other. Huperzine A may make solifenacin less effective for bladder symptoms, and solifenacin may blunt any benefit from huperzine A. It is not dangerous, but the two are pulling in opposite directions, so it is worth a word with your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does interact with Tolterodine?
Huperzine A raises acetylcholine while tolterodine blocks it, so each can work against the other. Huperzine A may make tolterodine less effective for bladder symptoms, and tolterodine may blunt any benefit from huperzine A. It is not dangerous, but the two are pulling in opposite directions, so it is worth a word with your prescriber.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope. Use the checker below to surface any medication, and submit a missing item if you take something we have not catalogued.
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