Methadone side effects

Severe pain should be treated with an opioid such as morphine, hydromorphone, methadone, or fentanyl. Moderate pain can be treated effectively in most cases with a weak opioid such as codeine or hydrocodone, usually in combination with acetaminophen. Meperidine should be avoided owing to its relatively short analgesic effect and its toxic metabolite, normeperidine. Normeperidine may accumulate with repeated dosing and can lead to central nervous system side effects including seizures. 

Methadone is not without side effects. Although it is less addictive than other opiates, methadone can be abused and requires monitored use. Common side effects include sedation and constipation. Methadone is also safer than other opiates in overdose but does require careful monitoring of respiratory status when an overdose occurs. 

Lower average doses of methadone have resulted not only from the drug being given to a broader population, but from heightened awareness of its side-effects and particular... 

As indicated, buprenorphine can offer a quicker option than methadone, with a three-day course reported to be effective for withdrawal from heroin (Cheskin et al. 1994). The side-effects of clonidine which render it unsuitable for community treatment can be manageable in the inpatient setting, although the drug is being superseded by lofexidine where that is available. Controlled studies have found clonidine and lofexidine to be equally effective in alleviating withdrawal symptoms in inpatient detoxification from heroin (Lin et al. 1997) and from methadone (Khan et al. 1997), with lofexidine resulting in less hypotension and fewer adverse effects. Another double-blind controlled study found lofexidine to be broadly as effective as a ten-day methadone detoxification in inpatient opiate withdrawal (Bearn et al. 1996). 

Methadone 200 mL GFJ 30 min before drug intake AUC 1, Cmax T) Fjjiax C/2 Side effects j, withdrawal symptoms (189)... 

After passage through the blood brain barrier, opioids have an anti-emetic effect (Blancquaert et al., 1986). Emesis inhibition is induced via blockade of an emesis centre located in a more central area of the formatio reticularis. This explains why the emetic effect of opioids is most apparent immediately after anministration, especially after rapid intravenous administration and is reduced or terminated when the compound has reached the CNS. The more hydrophilic opioids like morphine have stronger emetic side-effects than lipophilic compounds like methadone or fentanyl (Barnes et al., 1991), which are rapidly transported into the CNS. 

Kreek, M.J. Medical safety and side effects of methadone in tolerant individuals, J. Am. Med. Assoc. 1973, 223, 665-668. 

Pain research is a traditional and well established field within the pharmaceutical industry. Beginning with the isolation of morphine in a small pharmacy by Adam Serturner (1806), the next major breakthrough in pain treatment was achieved by the synthesis of acetylsalicylic acid by Felix Hoffmann in the Bayer Laboratories in Wuppertal (1897). Further outstanding contributions by the pharmaceutical industry were the first fully synthetic opioids pethidine (1939) and methadone (1946). Continued efforts up to now have resulted in many potent and clinically accepted analgesics with reasonable side effects and covering nearly all facets of pain treatment. However, pain treatment is far from being satisfactory in respect to more complex pain states, e.g. neuropathy, visceral pain or migraine. 

Normal sexual activity is associated with ovulation in most female mammals. Compounds affecting this process can adversely affect female libido. Ovarian failure induced by xenobiotic compounds has been associated with a decrease in libido in women. Certain types of oral contraceptives as well as drugs of abuse (methadone, cannabis, alcohol) cause decreases in female libido. The treatment for hirsutism, excessive growth of hair in both normal and abnormal locations, is the compound cyproterone acetate. It is an antiandrogen that has the side effect of severely decreasing libido in women. 

Because any opiate derivative will suffice to soothe heroin cravings associated with withdrawal, methadone, a synthetic opiate that has no sedating side effects, has been an effective treatment for heroin and morphine addiction for more than 30 years. The medication is taken orally and suppresses narcotic withdrawal for a period of 24 to 36 hours. Methadone can be taken continuously for 10 years or longer with no harmful side effects. 

Nausea is a side effect of all opiates. People who take opiates, including methadone, for a long period of time generally develop a tolerance for its nauseating effects. Vomiting, while common with other opiates such as heroin, is actually a rare side effect of methadone. These side effects are due to the stimulation by opiates of the part of the brain called the medulla, which controls nausea and vomiting. 

Another important side effect of all opiates on the central nervous system is respiratory depression. This is caused by an inhibitory effect on the brain stem, which is the part of the brain that controls breathing and other involuntary bodily systems such as heart beat, etc. Like nausea and vomiting, people who take methadone and other opiates normally develop a tolerance to this side effect. However, even people who have taken methadone for a long period of time can develop major respiratory depression. 

One of the most annoying physiological side effect of methadone use is a feeling of dryness in the mucous membranes of the mouth, eyes, and nose. This is caused by methadone reducing the secretion of saliva, tears, and mucous. Regular users of methadone refer to the dryness of the mouth as cotton mouth, since the feeling is akin to having one s mouth stuffed full of cotton. 

Another side effect of methadone is a change in a user s sexual desire and function. One theory is that opiates decrease testosterone levels in both men and women one small study of 29 methadone users found testosterone levels to be decreased by 40%. Methadone also inhibits sexual function by increasing the tone in the... 

Chronic constipation is also another troublesome side effect of prolonged methadone use. As discussed previously, methadone significantly slows the involuntary movements of the small and large intestines. By consuming a high-fiber diet and plenty of water, chronic users of methadone can reduce, but not eliminate, the occurrence of constipation. 

Besides being affected by medications and substances that affect the liver s metabolism, methadone itself affects the liver s metabolism of certain substances. A significant number of people who are taking methadone for heroin addiction also are HIV positive and are taking anti-HIV medications such as Desipramine (DMI) and zidovudine (AZT). Through its actions on the liver, methadone decreases the metabolism of these medications. Because of this, certain troublesome side effects of DMI and AZT, including nausea,... 

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