Clinical knowledge archive
Sedative Herb Stacking: Passionflower, Poppy, Corydalis and Your Medicines
Passionflower, California poppy and corydalis in Nerve Honey can each cause drowsiness, so combining the capsule with benzodiazepines, gabapentin, pregabalin, opioids, sleep aids, alcohol or other calming supplements needs a pharmacist's review first.
Updated November 6, 2026Sources linked below
Three calming herbs in one capsule
Passionflower, California poppy and corydalis each have sedating properties. Passionflower acts on GABA-A receptors in lab work, poppy alkaloids produced sedation in mice[1], and corydalis alkaloids reach the brain readily. In a single capsule at label doses, the combined effect is usually mild drowsiness, if any. The concern is what happens when you add something else that does the same thing.
What stacks with it
| Combined with | Likely effect | Advice |
|---|---|---|
| Benzodiazepines (lorazepam, alprazolam) | Added sedation; one case report of interaction | Prescriber review first |
| Gabapentin, pregabalin | Added dizziness and drowsiness | Pharmacist review; start apart |
| Opioids | Added sedation, slowed breathing risk | Avoid without medical approval |
| Sleep aids, antihistamines | Added sedation the next morning | Do not combine on the same night |
| Alcohol | Added sedation and impaired coordination | Avoid, especially at first |
| Other calming supplements | Valerian, kava, CBD, melatonin blends add up | Use one calming product at a time |
A published case described a patient on lorazepam who reported hand shaking, dizziness, throbbing and muscle fatigue after adding valerian and passionflower on their own[2]. Gabapentin and pregabalin, two first-line drugs for nerve pain[3], already list dizziness and sleepiness as common effects.
Driving and work
Drowsiness is the most reported side effect of passionflower[4]. Take the first few doses in the evening at home. Drive or operate machinery after a dose only once you know you are unaffected, and never after combining it with any item in the table.
Rare but serious
A case of passionflower toxicity with nausea, vomiting, drowsiness and an abnormal heart rhythm has been published[5]. Seek urgent care for fainting, a racing or irregular heartbeat, or breathing that feels slow or shallow.
The one-change rule
Start Nerve Honey on its own, at least a week apart from any other new medicine or supplement, so that if a side effect appears you know where it came from. Keep the symptom log from the protocol page and add a line for drowsiness.
Sources
- 1Rolland A, Fleurentin J, Lanhers MC, et al. Behavioural effects of the American traditional plant Eschscholzia californica: sedative and anxiolytic properties. Planta Med. 1991;57(3):212-216.
- 2Carrasco MC, Vallejo JR, Pardo-de-Santayana M, Peral D, Martín MA, Altimiras J. Interactions of Valeriana officinalis L. and Passiflora incarnata L. in a patient treated with lorazepam. Phytother Res. 2009;23(12):1795-1796.
- 3Finnerup NB, Attal N, Haroutounian S, et al. Pharmacotherapy for neuropathic pain in adults: a systematic review and meta-analysis. Lancet Neurol. 2015;14(2):162-173.
- 4National Center for Complementary and Integrative Health. Passionflower.
- 5Fisher AA, Purcell P, Le Couteur DG. Toxicity of Passiflora incarnata L. J Toxicol Clin Toxicol. 2000;38(1):63-66.