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

Background: 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. Methods: 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). Results: After removing duplicate reports, a total of 67 cases involving concomitant use of cocaine and CCBs were analyzed 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 "product use for unknown indication" (β = 0.33) as the strongest predictor 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. Conclusions: It is here suggested that 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.