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
Last reviewed 22 June 2026. Each interaction below lists the evidence its assessment drew on: some rest on studies of the exact pair, others on mechanism evidence, where a citation may support one part of the reasoning rather than the exact combination. The evidence line on each entry says which.
Additive CNS sedation
Amber Does interact with Clonidine?
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.
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 Guanfacine?
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.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive CNS depression
Amber Does interact with Alprazolam?
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.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Chlordiazepoxide?
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.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Diazepam?
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.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Lorazepam?
Passionflower and lorazepam both calm the nervous system through overlapping pathways. Combining them can mean stronger drowsiness and slower reactions.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Nitrazepam?
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.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Oxazepam?
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.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Temazepam?
Passionflower and temazepam both calm the nervous system through overlapping pathways. Combining them can mean stronger nocturnal sedation and a heavier morning hangover.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Zaleplon?
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.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Zolpidem tartrate?
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.
Evidence: Limited human data, based on case reports and a known mechanism.
Amber Does interact with Zopiclone?
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.
Evidence: Limited human data, based on case reports and a known mechanism.
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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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 methodologyA full supplement review, built around you, not a generic stack.
The free checker answers one interaction question at a time. A Distil report reviews the bigger picture: your goals, diet, medications, current supplements and any blood results you provide, then shows what appears worth keeping, changing, adding or leaving out.
- what your diet already covers, so you are not adding a capsule for something food is already handling
- which evidence-graded compounds are worth considering for your goals, and which were considered but left out
- what to keep, change or stop from what you already take, plus the order to introduce anything new
- how your medications and complete supplement stack fit together, with daily timing and a clear point for reassessment
The interaction check is one section of the full report. You also get the reasoning behind each recommendation and the evidence references used.
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