The cause of fibromyalgia is unknown; however, it is believed to involve a combination of genetic and environmental factors with half the risk attributed to each. The condition runs in families and many genes are believed to be involved.
Agonist: A substance that acts like another substance and therefore stimulates an action. Agonist is the opposite of antagonist. Antagonists and agonists are key players in the chemistry of the human body and in pharmacology.
Examples of opiate agonists include methadone and LAAM. These synthetic opiates help prevent cravings and withdrawal but do not produce a high or feelings of euphoria. An opiate antagonist is a drug that replaces opiate agonists at the receptor sites.This blocks the patient from experiencing the opiate effects of the agonist drug. Opiate antagonists include naloxone and naltrexone.Methadone is used therapeutically to treat addiction to opiates including heroin, morphine, OxyContin and other drugs. In the treatment of chronic opiate addiction, an opiate agonist can be used as maintenance therapy.piate antagonists include naloxone and naltrexone. Methadone is used therapeutically to treat addiction to opiates including heroin, morphine, OxyContin and other drugs. In the treatment of chronic opiate addiction, an opiate agonist can be used as maintenance therapy.