Passionflower and medications.
Passionflower is in the Distil supplement database, evidence Grade B. The page below lists every medication we have explicitly assessed it against.
Passionflower is a calming herb taken at 250 to 500mg of standardised extract, or 45 to 90 drops of liquid, used mainly for anxiety and sleep quality through its effect on GABA signalling. The Grade B evidence includes a pilot trial where it eased generalised anxiety with fewer effects on daytime performance than low-dose oxazepam, a sleep-quality trial in healthy adults, and pre-operative anxiety studies, so the support is real but rests on small studies rather than large definitive ones. The interaction angle is the part worth attention: it adds to the sedation of benzodiazepines and other CNS depressants, so combining them needs care, and there is a theoretical interaction with MAOIs. Pregnancy is a reason to avoid it. Side effects tend to be mild sedation, with occasional stomach upset or rare allergic reactions. Because the main effect is sedation, take it in the evening and keep it away from alcohol and sedating medication unless a prescriber has signed off. A gentle option for mild anxiety and sleep.
Below are the 12 documented pairs we have explicitly assessed for Passionflower: 12 amber. The pairs cluster around 2 mechanisms: Additive CNS sedation and Additive CNS depression. 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
Additive CNS sedation
Passionflower can make you drowsy, and clonidine commonly causes drowsiness and tiredness too. Taken together they may add to the sedation and slow your reactions more than either alone. Use with care, particularly around driving, and especially in the first weeks.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Passionflower can make you drowsy, and guanfacine commonly causes drowsiness and tiredness too. Taken together they may add to the sedation and slow your reactions more than either alone. Use with care, particularly around driving, and especially in the first weeks.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive CNS depression
Passionflower and alprazolam both calm the nervous system through overlapping pathways. Combining them can mean stronger drowsiness and slower reactions. Akhondzadeh 2001 found passionflower comparable to oxazepam for generalised anxiety, which gives you a sense of the additive potential.
Passionflower and chlordiazepoxide both calm the nervous system through overlapping pathways. Combining them can mean stronger drowsiness and slower reactions. Take care around driving or anything that needs full alertness.
Passionflower and diazepam both calm the nervous system through overlapping pathways. Combining them can mean stronger drowsiness and slower reactions. Akhondzadeh 2001 found passionflower comparable to oxazepam for generalised anxiety, which gives you a sense of the additive potential.
Passionflower and lorazepam both calm the nervous system through overlapping pathways. Combining them can mean stronger drowsiness and slower reactions.
Passionflower and nitrazepam both calm the nervous system through overlapping pathways. Combining them can mean stronger drowsiness and slower reactions, and nitrazepam's long action makes next-day grogginess more likely. Take care around driving the morning after.
Passionflower and oxazepam both calm the nervous system through overlapping pathways. Combining them can mean stronger drowsiness and slower reactions. Take care around driving or anything that needs full alertness.
Passionflower and temazepam both calm the nervous system through overlapping pathways. Combining them can mean stronger nocturnal sedation and a heavier morning hangover.
Passionflower and zaleplon both have a calming, sleep-promoting effect, so taking them together can add up to deeper-than-intended sedation and a heavier next-morning grogginess. Use with care, particularly around driving the next morning.
Passionflower and zolpidem both calm the nervous system through the same kind of pathway, so taking them together can mean stronger drowsiness and slower reactions. Take care around driving or anything that needs full alertness.
Passionflower and zopiclone both calm the nervous system through the same kind of pathway, so taking them together can mean stronger drowsiness and slower reactions. Take care around driving or anything that needs full alertness, especially the morning after.
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.
How we grade severity, choose what's in scope, and what we exclude.
Every call on this page is reasoned. We publish the full rubric for severity tiers, the medication inclusion logic, the evidence grades we accept, and what we deliberately leave out. About three thousand words. Worth reading once if you use this tool more than occasionally.
Read the full methodologyWant this checked across everything you take?
This page checks the pairs you enter. The personalised Distil report goes further:
- the same graded, cited interaction check across your whole stack, not just the pairs you thought to type in
- where your current routine may be leaving you short of your goals
- the evidence-backed compounds worth adding, and the ones worth dropping
It's a paid report: £79, or £49 for the first 25 customers. The interactions check is one section of it, and you can read a real one in full before you buy.
See a real sample reportSomething missing?
If a supplement or medication you take isn't in our autocomplete, tell us. We go through what people flag every week and add what's missing.