Adverse Drug Reactions Associated with Concomitant Use of Calcium Channel Blockers and Cocaine: An Analysis of FDA Adverse Events Reporting System Data

Recent drug enforcement activities have possibly suggested the presence of some calcium channel blocker antihypertensives in association with cocaine. The seizure revealed the possibility that the two drugs might have been used together for some unknown reasons. Hence, this study aimed at investigating the nature and frequency of adverse drug reactions (ADRs) reported in association with the concomitant use of calcium channel blockers (CCBs) and cocaine, using data from the FDA Adverse Event Reporting System (FAERS). After removing duplicate reports, a total of 67 cases involving concomitant use of cocaine and CCBs were analysed and were stratified into three groups based on the CCB involved: verapamil (n = 19), diltiazem (n = 30), and amlodipine (n = 18). Logistic regression analysis identified “completed suicide” (β = 0.35) and “product use for unknown indication” (β = 0.33) as the strongest predictors of fatal outcomes. Age revealed a modest negative association with fatal outcome (β = -0.93, intercept = 4.07). Concomitant substance use was reported in over 84% of cases. Frequently co-used substances included opioids, benzodiazepines, antidepressants, antihistamines and alcohol. Poly-drug use was most pronounced in the diltiazem group, which exhibited the highest burden of opioid and alcohol co-exposure. It is here suggested tat clinicians should exercise caution when managing individuals who use cocaine, due to the potential for increased toxicity and lethality when CCBs are co-used, either as part of a prescribed treatment or if CCBs are present as adulterants in cocaine.