Year: 2000
Type: article
Abstract: Use of methadoneOpiate dependence is a major public health problem associated with the transmission of deadly diseases (human immunodeficiency virus [HIV], hepatitis), criminal activity, accidental overdose, hospital admissions, and death.The treatment of opiate dependence is controversial, and in most patients, a lifelong duration is probably required.1 Methadone is a synthetic opiate primarily used in the detoxification and maintenance of patients who are dependent on opiates-particularly heroin-and the treatment of patients with chronic, severe pain.In the United States, methadone may be prescribed by physicians and dispensed by community pharmacies for analgesia as a Schedule II drug under the regulations of the Controlled Substances Act.However, when used for the treatment of opiate dependence, methadone's accessibility is restricted to practitioners, clinics, and pharmacies licensed by the Food and Drug Administration for this purpose. PHARMACOLOGY AND MECHANISM OF ACTIONMethadone is a synthetic, long-acting opioid with pharmacologic actions qualitatively similar to morphine and is active by oral and parenteral routes of administration.2 It is primarily a µ-receptor agonist and may mimic endogenous opioids, enkephalins, and endorphins and affect the release of other neurotransmitters-acetylcholine, norepinephrine, substance P, and dopamine.3 This accounts for its analgesic and antitussive properties, respiratory depression, sedation, decrease in bowel motility, increase in biliary tone, hormone regulation and increase of prolactin and growth hormone release, miotic pupils, nausea, and hypotension.Patients develop tolerance and physical dependence following repeated use.The tolerance may be only partial for most of the pharmacologic effects.An abstinence syndrome consisting of lacrimation, rhinorrhea, sneezing, gooseflesh, nausea, vomiting, fever, chills, tremor, and tachycardia occurs on abrupt discontinuation of the opiate or the administration of an antagonist such as naloxone hydrochloride.There is cross-tolerance and cross-dependence among the various opiates.This is the premise for using methadone in the detoxification and maintenance of heroin people addicted to heroin.Due to the long half-life and duration of action of methadone, the abstinence syndrome is delayed and prolonged but less severe than that from a shorter-acting opiate such as heroin. INDICATIONS AND DOSING MaintenanceMaintenance therapy is the long-term administration of methadone hydrochloride to patients who are dependent ............
Source: Western Journal of Medicine
Author: I. B Anderson
Institution: University of California, San Francisco
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W1971712648