Morphine is a powerful drug used to treat pain from cancer, multiple sclerosis, and other conditions generating pain in the elderly. According to a consensus statement by an international expert panel on opioids and severe pain in the elderly, with Dr. Joseph Pergolizzi of Johns Hopkins University as lead author, morphine is primarily metabolized in the liver and its metabolites are excreted by the kidneys. Thus, elderly patients with liver or kidney disease need lower dosages or longer dosing intervals.
Pergolizzi notes that elderly patients in general often have constipation prior to the use of opioids, and morphine makes the problem worse--morphine is extremely constipating compared with other opioids. Some elderly patients switch to a less-constipating drug because of the severity of their morphine-induced constipation. Some older patients have left clinical studies because they couldn't tolerate the constipation that morphine caused.
Dr. Ramsin Benyamin of the College of Medicine at the University of Illinois in Urbana-Champaign says constipation can occur with just one dose of morphine. He also says constipation is not a side effect that diminishes over time; consequently, this problem should be managed over the entire course of treatment with morphine among the elderly.
Contrary to the case with younger individuals, respiratory depression--a decreased breathing rate that may be inadequate for the body's needs--is an issue with morphine use among older people, especially in older individuals with serious pulmonary conditions, such as chronic bronchitis or chronic obstructive pulmonary disease. Pergolizzi notes this risk is worsened if elderly individuals also consume alcohol or take drugs that are central nervous system depressants, such as barbiturates or benzodiazepines.
Pergolizzi says that the thinking abilities--cognition--of elderly patients on a stable moderate dosage of morphine is generally unaffected; however, if the dosage is increased, this can cause cognitive impairment for up to seven days.
Immunosuppression refers to the decreased ability of the immune system to fight off bacterial and viral invaders because of one or more factors. Sometimes immunusuppression is planned, as with immunosuppressants given to organ donors so their body won't reject the organ.
In general, however, immunosuppression is not desirable, and is a particular problem with the elderly. Pergolizzi notes that morphine is the most immunosuppessive opioid drug. In contrast, buprenorphine, oxycodone and hydromorphone--all opioids--are significantly less immunosuppressive than morphine.