Levacetylmethadol (

INN Inns are generally establishments or buildings where travelers can seek lodging, and usually, food and drink. Inns are typically located in the country or along a highway; before the advent of motorized transportation they also provided accommo ...

), levomethadyl acetate (

USAN 280px, "Samguk Sagi" Book 04. Silla's Records. In 512, Usan-guk（于山國）was Ulleungdo（鬱陵島） Usan-guk, or the State of Usan, occupied Ulleung-do and the adjacent islands during the Korean Three Kingdoms period. According to th ...

), OrLAAM (trade name) or levo-α-acetylmethadol (LAAM) is a synthetic

opioid Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...

similar in structure to

methadone Methadone, sold under the brand names Dolophine and Methadose among others, is a synthetic opioid agonist used for chronic pain and also for opioid dependence. It is used to treat chronic pain, and it is also used to treat addiction to heroi ...

. It has a long duration of action due to its active

metabolites In biochemistry, a metabolite is an intermediate or end product of metabolism. The term is usually used for small molecules. Metabolites have various functions, including fuel, structure, signaling, stimulatory and inhibitory effects on enzymes, ...

Medical uses

LAAM is indicated as a second-line treatment for the treatment and management of

opioid dependence Opioid use disorder (OUD) is a substance use disorder characterized by cravings for opioids, continued use despite physical and/or psychological deterioration, increased tolerance with use, and withdrawal symptoms after discontinuing opioids. Op ...

if patients fail to respond to drugs like

buprenorphine Buprenorphine is an opioid used to treat opioid use disorder, acute pain, and chronic pain. It can be used under the tongue (sublingual), in the cheek (buccal), by injection (intravenous and subcutaneous), as a skin patch (transdermal ...

. LAAM is used as an

oral The word oral may refer to: Relating to the mouth * Relating to the mouth, the first portion of the alimentary canal that primarily receives food and liquid **Oral administration of medicines ** Oral examination (also known as an oral exam or or ...

solution of LAAM

hydrochloride In chemistry, a hydrochloride is an acid salt resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base (e.g. an amine). An alternative name is chlorhydrate, which comes from French. An archaic alternative n ...

at a concentration of 10 mg/mL in bottles of 120 and 500 mL under the brand name Orlaam. The first dose of LAAM for patients who have not started treatment with

is 20–40 mg. The first dose for patients who have been receiving

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 two to three times a week.

Pharmacology

Pharmacodynamics

LAAM acts as a

μ-opioid receptor The μ-opioid receptors (MOR) are a class of opioid receptors with a high affinity for enkephalins and beta-endorphin, but a low affinity for dynorphins. They are also referred to as μ(''mu'')-opioid peptide (MOP) receptors. The prototypical � ...

agonist. It also acts as a potent, noncompetitive α₃β₄ neuronal

nicotinic acetylcholine receptor Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral ner ...

antagonist.

Pharmacokinetics

LAAM undergoes extensive

first-pass metabolism The first pass effect (also known as first-pass metabolism or presystemic metabolism) is a phenomenon of drug metabolism whereby the concentration of a drug, specifically when administered orally, is greatly reduced before it reaches the system ...

to the active demethylated metabolite nor-LAAM, which is further demethylated to a second active metabolite, dinor-LAAM. These

are more potent than the parent drug.

Chemistry

LAAM, or levomethadyl acetate, is the ''levo'' isomer of acetylmethadol, or α-methadyl acetate. The ''dextro'' isomer, ''d''-

alphacetylmethadol Alphacetylmethadol ( INN), or α-acetylmethadol (AAM), is a synthetic opioid analgesic. Its levorotary enantiomer, levacetylmethadol, is an FDA-approved treatment for opioid addiction. Alphacetylmethadol is very similar in structure to methad ...

(''d''-α-acetylmethadol), is more potent but shorter acting. The ''levo'' isomer is also less toxic with an in mice of 110 mg/kg s.c. and 172.8 mg/kg orally as opposed to s of 61 mg/kg s.c. and 118.3 mg/kg orally for ''dl''-α-methadyl acetate. It has a

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depen ...

of 215 °C and a

molecular weight A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...

of 353.50. β-methadyl acetate also exists, however it is more

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subs ...

and less active than α-methadyl acetate and has no current medical use.

History

LAAM was approved in 1993 by the

U.S. Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

for use in the treatment of

. In 2001, LAAM was removed from the European market due to reports of life-threatening ventricular rhythm disorders. In 2003, Roxane Laboratories, Inc. discontinued Orlaam in the US.

Society and culture

Legal status

Before August 1993, LAAM was classified as a schedule I drug in the United States. LAAM is not approved for use in Australia and

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. At present, it is a Schedule II Narcotic controlled substance in the United States with a DEA ACSCN of 9648 and a national aggregate annual manufacturing quota of 4 grammes as of 2013.

References

External links

* * * {{Opioid receptor modulators Acetate esters Enantiopure drugs Dimethylamino compounds HERG blocker Mu-opioid receptor agonists Nicotinic antagonists Synthetic opioids