Levomethadyl Acetate

Levomethadyl acetate, also known as levo-α-acetylmethadol (LAAM) is a synthetic U.S. Food and Drug Administration for use in the treatment of opioid dependence. In 2001, the product ORLAAM was removed from the European market due to reports of severe cardiac-related adverse events. In 2003, Roxane Laboratories, Inc. discontinued ORLAAM in the US.^[1]

Indications

LAAM is indicated as a second-line treatment for the treatment and management of opioid dependence if patients fail to respond to drugs like buprenorphine. LAAM is not approved for use in Canada.

Chemistry and Pharmacology

Levomethadyl acetate is the levo isomer of α-methadyl acetate. The dextro isomer is more potent but shorter acting. The levo isomer is also less toxic with an LD50 in mice of 110mg/kg s.c. and 172.8mg/kg orally as opposed to LD50s of 61mg/kg s.c. and 118.3mg/kg orally for dl-α-methadyl acetate. It has a molecular weight of 353.50. β-methadyl acetate also exists, however it is more toxic and less active than α-methadyl acetate and has no current medical use.

Levomethadyl acetate undergoes extensive first-pass metabolites are more potent than the parent drug.

Dosing

LAAM is used as an oral methadone will be a little higher than the amount of methadone that was being taken every day, but not more than 120 mg. Afterwards, the dosage may be adjusted as needed. Unlike methadone, which requires daily administration, LAAM is administered three times a week.

References

1. ^ http://www.fda.gov/cder/drug/shortages/orlaam.htm