The role of newer opioids in geriatric anesthesia.

The unique features of remifentanil are its rapid clearance and rapid ke0, resulting in a rapid onset and offset of drug effect. It is tempting to speculate that these characteristics will make remifentanil an easy drug to titrate, and that clinicians will not need to consider patient covariates such as advanced age when choosing a dosing regimen. However, the rapid onset of drug effect may be accompanied by rapid onset of adverse events such as apnea and muscle rigidity. The rapid offset of drug effect can result in patients who are in severe pain at a time when the anesthesiologist is ill equipped to deal the problem, for example when the patient is in transit to the recovery room. It is thus important that when treating elderly patients anesthesiologists understand the proper dose adjustment required for the elderly. By adjusting the bolus and infusion doses, the anesthesiologist can hope to avoid the peaks and valleys that might expose these patients to risk. When the proper adjustment is made, the variability in remifentanil pharmacokinetics is considerably less than for any other intravenous opioid. This makes remifentanil the most predictable opioid for treatment of the elderly.