Interactions between cannabinoids and drugs may occur with the concomitant use of THC and/or CBD and other drugs. Interactions between cannabinoids and drugs are complex and have not been fully investigated yet. The purpose of this thesis is to identify interactions between cannabinoids, more precisely THC and CBD, and drugs. The aim of the thesis is to present the pharmacokinetic and pharmacodynamic mechanisms of these interactions according to the anatomical-therapeutic-chemical classification of drugs and to suggest course of action.
A review of interactions between THC or CBD and drugs was performed by using two online databases: Lexicomp and PubMed. The search for articles in the PubMed database was performed with the following search profile: «(thc OR cbd OR cannabinoids OR cannabis) AND drugs AND interactions« and limits: published in the period of 2015 – 2020, English language, humans. The literature was selected according to the predetermined inclusion and exclusion criteria.
We identified 541 potential interactions between THC or CBD and drugs in the Lexicomp database. Most of the identified interactions were type C and only three of them were type D. We did not identify any type X interaction. Of all the drugs that interact with THC or CBD most of them belong to the group N according to the anatomical-therapeutic-chemical classification. We included 16 articles in the literature review. Most of them discuss the interactions between CBD and antiepileptics and THC and central nervous system depressants. Pharmacokinetic interactions occur due to effects on metabolic enzymes or transport proteins where the pharmacokinetic of cannabinoids or drugs is altered. In pharmacodynamic interactions, THC most often potentiate the inhibitory effect of drugs acting on the central nervous system.
By knowing the mechanism of interactions, we can contribute to the prevention or reduction of the number of potential interactions. The use of the Lexicomp database makes sense to obtain information about potential interactions but for the final decision before an intervention, a critical evaluation of interactions is needed and additional literature review in the case of less well-founded interactions.