Levomethadyl acetate (LAAM) is a synthetic opioid agonist with actions qualitatively similar to morphine (a prototypic mu agonist) and affecting the central nervous system (CNS) and smooth muscle. Principal actions include analgesia and sedation. Tolerance to these effects develops with repeated use. An abstinence syndrome generally occurs upon cessation of chronic administration similar to that observed with other opiates, but with slower onset, more prolonged course, and less severe symptoms. LAAM exerts its clinical effects in the treatment of opiate abuse through two mechanisms. First, LAAM cross-substitutes for opiates of the morphinetype, suppressing symptoms of withdrawal in opiate-dependent individuals. Second, chronic oral administration of LAAM can produce sufficient tolerance to block the subjective "high" of usual doses of parenterally administered opiates. Since the introduction of levomethadyl in 1995, the manufacturer has received increasing reports of severe cardiac-related adverse events, including QT interval prolongation, Torsades de Pointes and cardiac arrest. Other cardiac-related adverse events have also been reported, including arrhythmias, syncope, and angina. These events led to the removal of levomethadyl from the European market in March 2001. A very small number of patients may benefit from levomethadyl, but the risk of continued distribution and use no longer outweighs the overall benefits.

Levomethadyl acetate:
https://drugs.ncats.io/drug/R3B637Y991

Levo-alpha-acetylmethadol (LAAM) is a man-made opioid drug intended to treat patients who are suffering from addiction to other opioids, such as heroin. Like other opioid addiction medications such as Methadone and Suboxone, LAAM works by blocking the neuroreceptors while producing minimal feelings of euphoria or cravings. LAAM was approved by the US Food and Drug Administration (FDA) in the early 1990s and has been shown to relieve pain and depress respiration; it also results in patient sedation. It is most closely associated with methadone, another opioid-based addiction treatment medication. LAAM is typically given to patients who do not respond well to other opioid addiction medications. However, LAAM lasts in the body much longer than methadone and, thus, can be given several times a week (as opposed to methadone, which must be given daily). Patients on a LAAM addiction treatment protocol must visit a treatment facility whenever the next dose is required. As an opioid, LAAM is extremely addictive. Using LAAM while drinking alcohol or taking other medications can be dangerous and lead to drowsiness, lack of consciousness and even death. Possible side effects of LAAM include flu-like symptoms, intestinal upset and mental issues including depression and anxiety.

Excerpt from addiction.com:
https://www.addiction.com/a-z/laam-levo-alpha-acetylmethadol/

Similar to methadone, it is a synthetic opiate used as a replacement therapy for illegal heroin use. It works by creating a cross-tolerance to other opiates, blocking the euphoric effects and controlling drug cravings. Waismann Method considers these medications substitutes that essentially swap one dependency for another. In addition to dependence, LAAM can lead to potentially fatal overdose, a severe withdrawal, and dangerous interactions. LAAM depresses the central nervous system and can cause a slowing of respiration. Combining it with other substances that have this effect can be deadly. These include other narcotics, alcohol, tranquilizers, sedatives, and hypnotics.

LAAM Warnings:
https://www.opiates.com/laam-warnings/

1996 article about Orlaam's Approval:
In a move that could make it easier for heroin addicts to adhere to treatment, New York State has approved a longer-acting alternative to methadone, the synthetic narcotic used to stave off the cravings of heroin addiction. Unlike methadone, which must be taken every day, the new drug, marketed under the brand name Orlaam, is taken three times a week. The decision to offer the alternative was embraced by treatment providers, who see it as a convenient option for the 42,000 patients in methadone treatment statewide - many of whom must show up at clinics daily for doses. Because of its potency and the potential for illegal sale, the Food and Drug Administration prohibits treatment clinics from allowing patients to take the new narcotic with them for use later in the week, as they often do with methadone.

1996 article about Orlaam's Approval:
https://www.nytimes.com/1996/09/06/nyregion/an-alternative-to-methadone-is-approved.html

Orlaam (levomethadyl acetate)

Side Effects:
Due to its potential for serious and possibly life-threatening, proarrhythmic effects, LAAM should be reserved for use in the treatment of opiate-addicted patients who fail to show an acceptable response to other adequate treatments for opiate addiction, either because of insufficient effectiveness or the inability to achieve effective dose due to intolerable adverse effects from those drugs.
RxList
Orlaam (Levomethadyl Acetate) Medication Guide: https://www.rxlist.com/orlaam-drug.htm
Common side effects of Orlaam (levomethadyl acetate hydrochloride) include: general feeling of being unwell (malaise) insomnia weakness abdominal pain constipation joint pain nervousness sweating difficulty ejaculating impotence decreased sex drive back pain chills swelling nausea vomiting diarrhea dry mouth flu symptoms hot flashes abnormal dreams anxiety depression euphoria headache drowsiness numbness cough runny nose yawning rash, and blurred vision

Recommendation to suspend the marketing authorisation for Orlaam (Levacetylmethadol) in The European Union (PDF 5 pages) (2001):
https://www.ema.europa.eu/en/documents/public-statement/public-statement-recommendation-suspend-marketing-authorisation-orlaam-levacetylmethadol-european_en.pdf

FDA Warns About Orlaam (2001):
http://www.methadone.org/library/fda_alert_2001_laam.html

Levomethadyl Acetate Hydrochloride Discontinued (2011 Federal Register PDF 2 pages):
https://www.govinfo.gov/content/pkg/FR-2011-06-06/pdf/2011-13884.pdf

LAAM (levo-alpha-acetylmethadol) is no longer approved for use in Europe and is not available for clinical use in the United States. In Europe, reports of several cases of ventricular tachycardia (torsade de pointes: TdP) occurring in patients treated with LAAM led the European Medicines Evaluation Agency (EMEA) to suspend authorization for its marketing in 2001. In the same year, responding to the reports of LAAM-related cases of TdP, the United States Food and Drug Administration (FDA) required the addition of a 'black box' warning on the LAAM label. The label states that LAAM should be used only for patients who failed treatment with other agents and that all patients receiving LAAM should have baseline electrocardiogram (ECG) screening and periodic monitoring. Because most clinics were reluctant to initiate such ECG assessments, the use of LAAM (not very high to begin with), dropped sharply. In 2003, Roxane Laboratories, the sole distributor of LAAM, announced its decision to discontinue its sale. However, it remains an FDA-approved therapeutic agent.

Levomethadyl (LAAM) No Longer Available For Clinical Use:
https://www.drugwarfacts.org/node/2686

Laam Information:
https://www.drugs.com/mmx/laam.html

Roxane Laboratories Orlaam (PDF 11 pages):
http://www.vidyya.com/2pdfs/orlaam.pdf

Levacetylmethadol:
a second-line treatment for the treatment and management of opioid dependence if patients fail to respond to drugs like methadone or buprenorphine. Unlike methadone, which requires daily administration, LAAM is administered two to three times a week. In 2001, levacetylmethadol 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.

The Jama Network 1972 https://jamanetwork.com/journals/jama/fullarticle/345021

The Jama Network 1976 https://jamanetwork.com/journals/jamapsychiatry/article-abstract/491556

The Jama Network 1977 https://jamanetwork.com/journals/jama/fullarticle/350769

• A synthetic opioid analgesic

It is a racemic mixture of alphacetylmethadol and betacetylmethadol, which are in turn racemic mixtures of levacetylmethadol (LAAM) and D-alpha-acetylmethadol and L-beta-acetylmethadol and D-beta-acetylmethadol, respectively

Alphacetylmethadol is a synthetic opioid analgesic. Its levorotary enantiomer, levacetylmethadol, is an FDA-approved treatment for opioid addiction. Alphacetylmethadol is very similar in structure to methadone, a widely-prescribed treatment for opioid addiction. In the United States, it is a Schedule I controlled substance under the Controlled Substances Act with an ACSCN of 9603 and a 2013 annual manufacturing quota of 2 grams. Studies in rats indicate that alphacetylmethadol also evokes the heroin-like discriminative stimulus effects.

Alphacetylmethadol:
https://drugs.ncats.io/drug/BXF83S0HEL

Synthetic opioid pain reliever very similar to methadone

Never marketed in the US

Betacetylmethadol is a synthetic narcotic analgesic under international control according to the UN Single Convention 1961.

Betacetylmethadol:
https://drugs.ncats.io/drug/905GLN509G

Synthetic opioid. A narcotic analgesic with a long onset and duration of action. It is used mainly in the treatment of narcotic dependence.