Aim: To evaluate whether effective methadone treatment affects cocaine use.
Methods: 421 consecutive patients admitted to a methadone maintenance clinic in Israel (1993-2002) were prospectively studied. Patients' urine samples were analyzed for cocaine during months 1 and 13.
Results: On admission 55(13.1%) of 421 patients had urine positive for cocaine and 366 had negative. Of the 55 cocaine-positive patients, 45(81.8%) stayed in treatment at least one year, as did 267(73%) of cocaine-negative. After one year (n=312) 31 of 45 cocaine users stopped and 25 of 267 started. Methadone dose was highest in 31 patients who stopped cocaine (176.1+/-42.1 mg/ day), followed by 14 who did not stop (161.4+/-37.5 mg/day), and 25 who started during treatment (122.9+/-48.7 mg/day), or 242 who never used cocaine (119.5+/-48.4 mg/day) (ANOVA, F=15.6, p<0.0005).
Conclusions: High methadone dose may reduce cocaine use in patients addicted to both heroin and cocaine.