The physiological effects of morphine sulfate and fentanyl citrate on postoperative pulmonary function demonstrate varying degrees of respiratory depression related to dose, route of administration and pre-existing pathologies. Current postoperative analgesic therapies that include concomitant use of narcotic agonists and nonsteroidal anti-inflammatory drugs require adjustment of drug dosages to provide adequate pain relief while avoiding drug-induced complications. Specific nursing considerations include understanding therapeutic and adverse effects of these agents on pain and ventilation, continuous pain assessment and early recognition and treatment of respiratory depression.