Understanding the Agent, Part II: Adverse Effects

Abstract

The decision to prescribe or use opioids—whether short term or long term—must be grounded in a full understanding of the drug class and the current evidence for both benefit and risk. Opioids remain some of the most dangerous drugs in the therapeutic armamentarium and confer a high degree of morbidity and mortality. Adverse effects of the class affect virtually every physiologic system, including neuropsychiatric, cardiovascular, respiratory, immunologic, endocrine, gastroenterologic, urinary, and dermatologic. Tolerance to the analgesic (and euphoric) effects of opioids is almost universal with prolonged use, and tolerance to some but not all of the adverse effects is common as well. Reduced efficacy with chronic use often leads to dose escalation which heightens the risks. Opioid-induced hyperalgesia is a commonly seen phenomenon whereby chronic use actually increases pain sensitivity; the only rational treatment decision in this situation is to reduce or eliminate opioid therapy. Last but certainly not the least, the risks of physical and psychological dependence and addiction and the grim consequences of these conditions are far more prevalent than was publicized 20 years ago.