ACUTE EFFECTS OF INHALED AND IV COCAINE ON AIRWAY DYNAMICS

Background: Wheezing has been reported by 32% of habitual smokers of c rack cocaine, and several cases of crack-related acute exacerbations o f asthma have been reported. Study objective: To compare the acute eff ects of physiologically active doses of smoked cocaine base and IV coc aine hydrochloride (HCl), a subphysiologic dose of cocaine base (smoke d ''placebo''), and IV saline solution placebo on bronchomotor tone, s ubjective level of intoxication, and cardiovascular responses in healt hy habitual crack users. Design: A single-blind crossover study in whi ch the order of route of administration (inhaled vs IV) was random but placebo always preceded the active drug.Subjects: Fourteen healthy, n onasthmatic current crack-smoking subjects, 34 to 48, years of age, wi th a history of previous IV cocaine use (1 to 12 times per lifetime). Methods: Heart rate, BP, self-rated level of intoxication (scale of 0 to 10), and measurements of airway resistance (Raw) and specific airwa y conductance (SGaw) were recorded during separate sessions before and 3 to 5, 10, 15, and 30 min after administration of smoked cocaine bas e (38.5+/-2.3 [SEM] mg), smoked placebo (2.3+/-0.9 mg cocaine base), I V cocaine HCl (30.0+/-2.0 mg), and IV placebo (saline solution). Resul ts: Both smoked active cocaine and IV cocaine HCl caused comparable, s ignificant (p<0.05) peak levels of acute intoxication (6.7+/-0.7 and 7 .3+/-0.8, respectively) and increases in heart rate from baseline (29. 6+/-2.9% and 21.4+/-3.7%, respectively, at 5 min), However, only smoke d active cocaine caused significant decreases from baseline in SGaw (2 5.4+/-6.3% at 5 min), in contrast to nonsignificant changes after IV c ocaine HCl (5.6+/-7.0% increase) and smoked placebo (10.2+/-6.0% decre ase). Conclusions: Smoked cocaine base, but not systemically administe red cocaine HCl, causes acute bronchoconstriction that is probably med iated by local airway irritation and could account for reports of crac k-induced wheezing and asthma attacks in nonasthmatic and asthmatic in dividuals, respectively.