Levomethadyl acetate hydrochloride (also known as LAAM) was approved in 1993 by the U.S. Food and Drug Administration for use in the treatment of opioid dependence. Unlike methadone, which requires daily administration, LAAM is administered three times a week. Eissenberg and colleagues compared the clinical efficacy of different dosages of LAAM.

Patients in the randomized, controlled study were assigned to one of three treatment groups, with the drug given on Mondays, Wednesdays and Fridays: low-dose LAAM (25 mg, 25 mg and 35 mg), medium-dose LAAM (50 mg, 50 mg and 70 mg) and high-dose LAAM (100 mg, 100 mg and 140 mg). The Friday dosages were higher to compensate for the longer dosage interval between Friday and Monday. The low-, medium- and high-dose groups had 62, 59 and 59 patients, respectively. Treatment goals were established for each patient, and individual and group therapy was provided. Patients' self-reports of illicit drug use and observed urine specimens were also obtained on the dosing days. Of the 180 patients who entered the study, 108 (60 percent) completed the entire 17-week study. No significant differences in retention were noted among the three treatment groups.

The percentage of patients who remained abstinent from opioid use (as verified by urine samples) increased as the LAAM dosage increased, with 11 percent of the low-dose group and 14 percent of the medium-dose group remaining abstinent for four consecutive weeks, compared with 34 percent of the high-dose group. Self-reported heroin use decreased to a greater degree in the high-dose group. After 16 weeks of LAAM treatment, patients in the high-dose group reported that they used heroin on 2.5 days of the previous 30 days, compared with 4.1 days and 6.3 days of the previous 30 days in the medium- and low-dose groups, respectively. Adverse effects were not dosage-related, and the most common adverse effect was constipation.

The authors conclude that LAAM treatment of opioid dependence has several advantages over the more commonly used methadone treatment—administering doses three times a week is more convenient and decreases the need for patients to take their medication at home. High-dose LAAM appears to be more effective than lower doses in decreasing heroin use.