Health News. Lots of resources and information

Methadone is a synthetic opioid analgesic which is indicated for the treatment of severe pain in patients unable to take morphine. It is effective orally, rectally and by injection. Methadone is contraindicated (or should be used with great caution) in patients who are frail, elderly or confused and in those with significant hepatic or renal impairment, as the risk of toxicity is higher. The side effects of methadone are similar to morphine except that cumulative toxicity may occur, usually heralded by sedation and confusion.     Administration of methadone is complicated by the drug’s complex pharmacokinetics. After a single dose, the half-life is about 15 hours but the duration of action is only 4-6 hours. With continued therapy, the half-life increases to 2-3 days and it is usually necessary to reduce both the dose and frequency of administration.• Failure to reduce the frequency of administration after the first few days -will predispose to cumulative toxicity with sedation and narcosis.     Pethidine is a synthetic opioid drug used for the treatment of severe acute pain. It has a therapeutic ceiling related to CNS toxicity and should not be used in the management of chronic cancer-related pain.     Accumulation of norpethidine occurs in patients given high or frequent doses and those with significant renal impairment, causing CNS excitation with agitation, tremor, myoclonus and seizures. The myoclonus and seizures are unresponsive to naloxone and are treated with benzodiazepines and anticonvulsants.• Pethidine given in high dose or in the presence of renal impairment leads to CNS irritation and seizures and it should not be used for chronic cancer-related pain.*57\55\2*