Controlled clinical study of naltrexone side effects comparing first-day doses and maintenance regimens.

In a controlled double-blind clinical study, 42 patients reported side effects and severity of side effects to naltrexone on three different first-day doses and maintenance dosage regimens. Initiating doses of 25, 100, and 150 mg were administered. The maintenance regimens involved 350 mg of naltrexone per week for 4 weeks with drug administration in Group A, five times weekly; in Group B, three times weekly; and in Group C, twice weekly. All three groups received identical doses for the last dosage administered each week. The first-day doses produced no significant quantitative difference in side effects. Overall, the three groups reported little difference in side effects. Nonetheless, the regimen with the least number of patients reporting side effects daily was that of Group B. In no case, regardless of dose or dosage regimen, did any patient have side effects of such a nature as to require termination of their participation in the study.