Table 1.

Cannabidiol–Psychoactive Drug Interactions²²

Name of drug	Class of drug	Mechanism of interaction	Clinical suggestions when co-administered with CBD
Carbamazepine	Anti-epileptic drug	Will decrease the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism.	Consider an increase in cannabidiol dosage (based on clinical response and tolerability) when co-administered.
Lamotrigine	Anti-epileptic drug	CBD will increase the level or effect of lamotrigine by inhibiting UGT2B7 activity.	Consider reducing the dose when concomitantly using UGT2B7 substrates such as morphine, losartan, diclofenac, tamoxifen, and ibuprofen.
Oxcarbazepine	Anti-epileptic drug	Will decrease the level or effect of CBD by affecting hepatic/intestinal enzyme CYP3A4 metabolism.	Consider an increase in CBD dosage (based on clinical response and tolerability) when co-administered with a strong CYP3A4 inducer.
Phenobarbital	Anti-epileptic drug	Will decrease the level or effect of CBD by affecting hepatic/intestinal enzyme CYP3A4 metabolism or CYP2C19 metabolism. CBD discreetly potentiates the anticonvulsant effect of phenobarbital.	Consider an increase in CBD dosage (based on clinical response and tolerability) when co-administered with a strong CYP3A4 inducer. Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when co-administered.
Phenytoin	Anti-epileptic drug	Will decrease the level or effect of CBD by affecting hepatic/intestinal enzyme CYP3A4/CYP2C19 metabolism. CBD may potentiate the anticonvulsant effects of phenytoin.	Consider an increase in CBD dosage (based on clinical response and tolerability) when co-administered with a strong CYP3A4 inducer. Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when co-administered.
Chlordiazepoxide Clonazepam Ethosuximide	Benzodiazepine	CBD reduces the anticonvulsant effects of these drugs	Consider an increase in the dose of these drugs when co-administered.
Clobazam or Diazepam	Benzodiazepine	CBD will increase the level or effect of clobazam or diazepam by affecting hepatic enzyme CYP2C19 metabolism. CBD increases clobazam plasma concentrations.	Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when co-administered.
Lorazepam	Benzodiazepine	CBD will increase the level or effect of lorazepam by decreasing its metabolism and potentially inhibit UGT2B7 activity.	Consider reducing the dose when concomitantly using UGT2B7 substrates.
Morphine	Opioid	CBD will increase the level or effect of morphine.	CBD may potentially inhibit UGT2B7 activity. Consider reducing the dose when concomitantly using UGT2B7 substrates.
Desipramine	Tricyclic anti-depressant	Desipramine will increase the level or effect of CBD by affecting hepatic/intestinal enzyme CYP3A4 metabolism.	Consider reducing the CBD dose when co-administered with a moderate CYP3A4 inhibitor.
Imipramine	Tricyclic anti-depressant	CBD will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism.	Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when co-administered.
Trimipramine	Tricyclic anti-depressant	CBD will increase the level or effect of trimipramine by affecting hepatic enzyme CYP2C19 metabolism.	Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when co-administered.