Methadone pain relief

Davis MP, Walsh D Methadone for relief of cancer pain A review of pharmacokinetics, pharmacodynamics, drug interactions and protocols of administration. Support Care Cancer 2001 9 73. [PMID 11305074]... 

Methadone and opiates were first used for pain relief, and are still chiefly used in that area of medicine. It is important to remember that methadone and other opiates do not exert their pain control by altering a person s sensitivity to pain. Rather, methadone and other opiates interfere with the transmission of pain impulses from the nervous system to the brain. They accomplish this by a variety of methods. First, they decrease the transmission of nerve signals that conduct pain messages from various parts of the body to the spine. Secondly, they prevent production of neurochemicals that transfer this pain information to the spine. Finally, they mimic the actions of endorphins, which are the body s own pain-controlling chemicals. While methadone and other opiates work quite well to control pain, they do not affect touch, vision, or hearing. 

Ketoprofen reduced morphine-associated respiratory depression, and did not alter morphine pharmacokinetics. Similarly, diclofenac did not alter morphine pharmacokinetics in one study. Improved pain relief and reduced adverse effects have been found when morphine was given with lomoxicam, ketoprofen, or ketorolac. However, in another, diclofenac slightly increased respiratory depression despite reducing morphine use, possibly because of persistent levels of an active metabolite of morphine. Diclofenac did not affect the pharmacokinetics or analgesic effects of codeine in healthy subjects. Intramuscular diclofenac did not affect the pharmacokinetics of methadone solution in cancer patients. Ibuprofen did not appear to interact... 

Methadone, a synthetic narcotic, may be used for the relief of pain, but it also is used in the detoxification and maintenance treatment of those addicted to narcotics. Detoxification involves withdrawing the patient from the narcotic while preventing withdrawal symptoms. 

On rare occasions, when pain is not relieved by the narcotic analgesics alone, a mixture of an oral narcotic and other drugp may be used to obtain relief. Brampton s mixture is commonly used to identify these solutions. In addition to the narcotics, such as morphine or methadone, other dragp may be used in the solution, including antidepressants, stimulants, aspirin, acetaminophen, and tranquilizers. The pharmacist prepares the solution according to the primary health care provider s instructions. 

For the relief of pain arising from spasm of smooth muscle, as in renal or biliary colic, morphine is frequently employed. Other measures including antispasmodics such as atropine, atropine substitutes, theophylline, nitrites, and heat may be employed first however, if they are ineffective, meperidine, methadone, or opiates must be used. Morphine relieves pain only by a central action and may aggravate the condition producing the pain by exaggerating the smooth muscle spasm. Morphine may also be indispensable for the relief of pain due to acute vascular occlusion, whether this be peripheral, pulmonary, or coronary in origin. In painful acute pericarditis, pleurisy, and spontaneous pneumothorax, morphine is likewise indicated. Carefully chosen and properly spaced doses of codeine or morphine may occasionally be necessary in pneumonia to control pain, dyspnea, and restlessness. Traumatic pain arising from fractures, bums, etc., frequently requires morphine. In shock, whether due to trauma, poisons, or other causes, morphine may be required to relieve severe pain. 

Methadone is used as an analgesic for the relief of moderate to severe pain. It is effective in conditions in which the analgesic effect of morphine is desirable, and it exerts a satisfactory antitussive action. 

When used as a cough suppressant, methadone is taken in a liquid or tablet form in very small (1-2 mg) doses every four to six hours. For relief of moderate to severe pain, it is generally given as a tablet or as an intramuscular injection, 2.5-20 mg every three to four hours. When used in heroin detoxification and methadone maintenance programs, it is given as oral tablets, biscuits, or liquid, 20-120 mg every 24-48 hours. 

Methadone is used clinically (1) for relief of pain, (2) to treat opioid abstinence syndrome, and (3) to treat heroin addicts in an attempt to wean them from illicit IV drug use. ... 

The primary uses of methadone hydrochloride (Dolo-phine, others) are relief of chronic pain, treatment of opioid abstinence syndromes, and treatment of heroin users. It is not used widely as an antiperistaltic agent. It should not be used in labor. 

Propoxyphene (65 mg every 4 hours as needed) is indicated in the relief of mild to moderate pain. It is structurally very similar to methadone and possesses four stereoisomers. Dextropropoxyphene is an analgesic with a potency two-thirds that of codeine. Levopropoxyphene is an antitussive but lacks analgesic properties. 

Metopon is satisfactory as a drug for oral use in the relief of chronic pain, but it is difficult and costly to prepare and therefore has not become a widely used substitute of morphine. Morphine, because of its cheapness, reliability, and rapidity of action, remains the drug of choice for conditions requiring relief of severe pain for periods of less than 2 weeks. Over a longer period, metopon and methadon may be more suitable drugs. 

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