Cognitive effects of opioids.

Although opioid analgesics are safe and effective tools for the treatment of moderate to severe pain, there remain large gaps in understanding of the effects of these drugs on the many dimensions of functioning. This article summarizes the biomedical evidence addressing cognitive effects of the opioid analgesics. Current evidence indicates that cognitive function can be influenced by use of opioid analgesics, although the effects vary between drugs, are thought to be most significant with mixed-activity drugs, codeine, propoxyphene, and meperidine, and are generally most concerning during the first few days after starting opioid therapy, before tolerance develops. Blanket policies regarding the activities of driving and working are inappropriate; this issue is best addressed on a patient-specific basis.