A historically controlled trial of tyrosine for cocaine dependence

Cocaine dependence continues to be a major public health problem and efforts to develop pharmacotherapies have been disappointing. Chronic cocaine use is believed to cause catecholamine depletion and similarities exist between cocaine withdrawal and major depression. Tyrosine is the dietary precursor to catecholamines and has yielded positive results in small trials of its antidepressant efficacy. Tyrosine 2 g every 8 hours was administered on an open-label basis to 49 cocaine-dependent individuals, as an adjunct to intensive out-patient drug abuse counseling. Retention in treatment at 90 days was compared to data from a control group of 80 subjects who had received 10 mg of imipramine per day in an earlier trial. Median retention was 17 days in both groups. No side effects were reported by the subjects receiving tyrosine. These results do not support the utility of tyrosine in the treatment of cocaine dependence.