Forty-six patients with moderate to severe pain caused by orthopedic injuries, burns, multiple trauma, or intraabdominal conditions were treated with intravenous (IV) nalbuphine hydrochloride (Nubain; DuPont Pharmaceuticals, Wilmington, DE) by paramedics before arrival at the hospital. Patients who weighed less than 60 kg received 15 mg nalbuphine, and patients weighing greater than 60 kg received 20 mg nalbuphine. Forty-one of 46 patients (89%) experienced pain relief from nalbuphine, with maximum relief occurring within 15 minutes after the administration of the drug. Two addicted patients received no pain relief. There were no untoward side effects following nalbuphine administration, and the patients' heart rates, mean arterial pressures, and respiratory rates remained constant and stable throughout the study period. Repeated assessment of the patient by paramedics in the field was not impaired by nalbuphine treatment. In summary, nalbuphine hydrochloride is a useful and safe analgesic drug for IV use by paramedics in the prehospital setting.