The following is a summary of “Smoked cannabis reduces peak cocaine plasma levels and subjective effects in a controlled drug administration study of polysubstance use in men,” published in the February 2023 issue of Drug and Alcohol Dependence by Murray et al.

The insufficient characterization of outcomes and potential risks associated with common drug combinations is a concern despite the high prevalence of polysubstance use. The co-occurrence of cannabis and cocaine use is common; however, the potential impact of drug-drug interactions on co-use maintenance remains poorly understood. The objective of this study, which was conducted in a double-blind, placebo-controlled manner, was to assess the physiological and subjective impacts of the inhalation of cannabis and cocaine and to identify potential factors that may contribute to the continued use of this drug combination. 

A group of 9 male individuals who reported using cocaine and cannabis and did not seek medical treatment was recruited as healthy volunteers. They underwent a 13-day inpatient protocol. On the days of the session, the administration of cannabis [0.0 or 5.6 % tetrahydrocannabinol (THC)] was carried out 28 minutes before cocaine (0, 12, or 25 mg). 

The study incorporated dependent measures, such as pharmacokinetic evaluation of THC and cocaine and their corresponding metabolites, in conjunction with subjective and cardiovascular impacts. The administration of active cannabis containing 5.6% THC resulted in elevated plasma concentrations of THC and its metabolite 11-nor-9-carboxy-Δ9-THC (THCCOOH) and heightened subjective ratings of cannabis effects and heart rate compared to the administration of inactive cannabis. The administration of cocaine resulted in a dose-dependent elevation of plasma cocaine and its metabolites and subjective ratings of cocaine-induced effects. Pre-treatment with active cannabis resulted in a reduction of plasma concentrations of cocaine and its metabolites. In addition, the use of cannabis has been observed to reduce the effects of cocaine on appetite and anxiety. The administration of cannabis before cocaine consumption resulted in a modification of the individual’s perception of the drug’s effects and a decrease in the maximum concentration of cocaine in the bloodstream. Further investigations are warranted to examine supplementary dosages of each medication and their potential influence on the reinforcing properties of cocaine.

Source: sciencedirect.com/science/article/abs/pii/S037687162200494X