Titration of Intravenous Hydromorphone

This is an exploratory, hypothesis-generating safety and efficacy study for patients who come to the ER in acute (less than 7 days in duration) severe pain. Patients with chronic pain will not be enrolled. Eligible patients will receive up to a maximum of 4 mg IV hydromorphone over a 4 hour period. Hydromorphone will be given as 1 mg increments based on how the patient responds to the question, "Do you want more pain medicine?". This question will be asked repeatedly 30 minutes after the patient answers "no" or 30 minutes after the most recent dose of IV hydromorphone (which occurs if the patient answers "yes"). Up to 10% (approximately 30 patients) will serve as a pilot at the start of the study.