These add. No metabolic interaction is required and none of them has to be strong on its own: sedation, impaired coordination and impaired judgement stack, and at sufficient combined load so does loss of airway protection and depression of breathing. The practical trap is that tolerance to one agent does not confer tolerance to the combination, and that the dose of each that felt unremarkable alone is the dose people then take together.
A CYP finding elsewhere in this result compounds this one: an inhibitor that raises the blood level of a sedative raises the depth of sedation without any change in what was taken.
What to watch for. Deepening drowsiness, slurred speech, unsteadiness, difficulty being roused, slow or shallow breathing, snoring or gurgling in someone asleep. Someone who cannot be woken is an emergency, not someone sleeping it off.
Moderate Endocannabinoid tone raised from 3 directions: Kava + Hops (8-prenylnaringenin)
Mechanism: stacked endocannabinoid modulation
This stack acts on more than one of the routes that terminate endocannabinoid signalling — FAAH inhibition, MAGL inhibition, alongside a declared CB1 agonist. The mechanisms are separate, so in principle they are not redundant. Three things should be said plainly about what follows from that. The individual inhibition figures behind most of these botanicals come from in-vitro enzyme assays at micromolar concentrations, and for most of them there is no human pharmacokinetic study establishing that an ordinary dose reaches those concentrations. The combination has not been studied in people at all. And more inhibition is not straightforwardly more effect: sustained complete MAGL blockade produces functional CB1 desensitisation in animals, so the system pushes back.
Several of the plants on this axis carry a second, better-documented pharmacology that is easy to overlook while attending to the cannabinoid one — estrogenic activity for hops and the isoflavones, CYP and P-glycoprotein inhibition for pepper and turmeric, GABA-A modulation and a liver signal for kava. Those are the effects most likely to actually show up.
What to watch for. Unexpectedly strong or prolonged effect from an unchanged amount of a cannabinoid, and sedation if any of the same plants are also on the CNS-depression axis.
A clean result means NO DOCUMENTED INTERACTION IN THIS DATASET. It does not mean safe, and it is not a clearance. Most substances are not in this dataset at all, and for many pairs that are, nobody has ever studied the combination.
Serotonergic drugs and the serotonin-toxicity mechanism
Dietary tyramine and L-dopa loads
The major cytochrome P450 pathways: CYP3A4, CYP2D6, CYP1A2, CYP2C9, CYP2C19 — inhibition and induction
P-glycoprotein inhibition and induction
11β-HSD2 inhibition (the licorice mechanism) and the potassium consequences that follow it
QT prolongation as an additive pharmacodynamic axis
Culinary seasonings and common foods with documented pharmacological activity
A selected set of narrow-therapeutic-index drugs where those shifts matter most
The endocannabinoid enzymes and transport: FAAH, MAGL, endocannabinoid membrane transport, CB1 and CB2
Additive CNS depression and GABA-A positive modulation — the alcohol / benzodiazepine / opioid / kava axis
The phytocannabinoids delta-9-THC, cannabidiol and the converted cannabinoids, as both substrates and inhibitors
Synthetic full CB1 agonists as a class, and why they are pharmacologically unlike cannabis
CYP2E1, and phase-2 glucuronidation and sulfation where a specific entry names them
The sedative and potentiator botanicals of the kava literature, and dietary L-dopa from Mucuna
Not in this dataset
Any substance not named in this dataset — which is most substances. There are tens of thousands of marketed drugs and this table holds fewer than a hundred entries.
Phase-2 conjugation (UGT, SULT, NAT2, COMT) except where a specific entry names it. The oilahuasca corpus turns heavily on phase 2 and this engine models it only in passing.
Pharmacogenomics. CYP2D6 and CYP2C19 are strongly polymorphic; a poor metaboliser and an ultra-rapid metaboliser can have opposite outcomes from the same pair, and this engine does not know your genotype.
Dose, timing, duration, formulation and route — all of which change whether a documented interaction is clinically real for you.
Renal and hepatic impairment, age, pregnancy, and body composition.
Bleeding and antiplatelet risk, hypoglycaemia, anticholinergic load, and most other pharmacodynamic axes beyond the ones listed above. Additive CNS depression and GABA-A modulation ARE now modelled — see the covers list — but the absence of a sedation finding still only means the agents you named are not on that axis in this dataset.
Herb–herb interactions outside the named entries, and essentially the whole botanical world: most plants have no interaction literature at all.
Allergy, intolerance, and contamination or adulteration of unregulated products.
Anything published after the last-reviewed date below.
Bleeding and antiplatelet risk, which is the mechanism that matters most for garlic, ginkgo and several other common supplements. It is not modelled at all, so a clean result says nothing about it.
Whether any of the natural FAAH, MAGL or transport inhibition reported in vitro occurs at all at a dose a person would take. For most of these compounds nobody has measured it.
The actual contents of an unregulated cannabinoid product. This engine models named compounds; an unidentified isomer or side-product in a converted-cannabinoid product is outside it by construction.
Dose. Every cannabinoid interaction here scales with dose, and consumer product labelling for this category is repeatedly found inaccurate in published surveys.
Inhalation-specific hazards — thermal degradation products, diluents chosen for rheology rather than for inhalation toxicology, and carrier and adulterant contamination.
101 substances, 33 mechanisms,
101 citations. Last reviewed .
Primary literature (every DOI resolved against the Crossref API) and FDA drug labelling. There is no free, openly-licensed, comprehensive drug-interaction dataset to draw on; NLM retired its Drug Interaction API on 2024-01-02 and DrugBank's interaction set is a commercial licence.
References
Chua HC, Christensen ETH, Hoestgaard-Jensen K, et al. (2016). Kavain, the Major Constituent of the Anxiolytic Kava Extract, Potentiates GABA-A Receptors: Functional Characteristics and Molecular Mechanism. PLOS ONE. doi:10.1371/journal.pone.0157700
Benke D, Barberis A, Kopp S, et al. (2009). GABA-A receptors as in vivo substrate for the anxiolytic action of valerenic acid, a major constituent of valerian root extracts. Neuropharmacology. doi:10.1016/j.neuropharm.2008.07.041
Sarris J, Kavanagh DJ, Byrne G, Bone KM, Adams J, Deed G (2009). The Kava Anxiety Depression Spectrum Study (KADSS): a randomized, placebo-controlled crossover trial using an aqueous extract of Piper methysticum. Psychopharmacology. doi:10.1007/s00213-009-1549-9
Ligresti A, Villano R, Allarà M, Ujváry I, Di Marzo V (2012). Kavalactones and the endocannabinoid system: the plant-derived yangonin is a novel CB1 receptor ligand. Pharmacological Research. doi:10.1016/j.phrs.2012.04.003
Tung C-W, Fung K-M, Hsu C-C, Tseng T-S (2021). Discovery of 8-prenylnaringenin from hop (Humulus lupulus L.) as a potent monoacylglycerol lipase inhibitor for treatments of neuroinflammation and Alzheimer's disease. RSC Advances. doi:10.1039/d1ra05311f
Schlosburg JE, Blankman JL, Long JZ, et al. (2010). Chronic monoacylglycerol lipase blockade causes functional antagonism of the endocannabinoid system. Nature Neuroscience. doi:10.1038/nn.2601
Nicolussi S, Gertsch J (2015). Endocannabinoid transport revisited. Vitamins and Hormones. doi:10.1016/bs.vh.2014.12.011
Ligresti A, De Petrocellis L, Di Marzo V (2016). From Phytocannabinoids to Cannabinoid Receptors and Endocannabinoids: Pleiotropic Physiological and Pathological Roles Through Complex Pharmacology. Physiological Reviews. doi:10.1152/physrev.00002.2016
Every DOI above was resolved against the Crossref API on 2026-09-09 and the returned
title checked against the one printed here. Three DOIs in the first draft resolved to real but different
papers and were corrected before publication.