Comparison of ketorolac-chlorpromazine with meperidine-promethazine for treatment of exacerbations of chronic pain.

Background: The aim was to compare the efficacy and safety of a combination of intramuscular ketorolac and chlorpromazine for the treatment of acute exacerbations of chronic pain with the more commonly used regimen of intramuscular meperidine and promethazine.

Methods: Use-effective case series were drawn from a real-life, rural emergency department practice, in which 200 consecutive patients coming to a rural emergency department with acute exacerbations of chronic pain syndromes were assigned on an every-other basis in a single-blind fashion to one of the two treatment conditions. Patients were given intramuscular doses of either 60 mg of ketorolac plus 50 mg of chlorpromazine (75 mg of chlorpromazine for patients weighing more than 100 kg), or 50 mg of meperidine plus 25 mg of promethazine (50 mg of promethazine for patients weighing more than 75 kg); patients weighing more than 100 kg were given 1.5 doses. Patients older than 65 years or whose blood pressure at the time of injection was less than 110/70 mmHg were given half-doses. Patients could receive one additional half-dose injection if they had no results within 30 to 60 minutes after the first injection. Patients were assessed on self-report and on a verbal and visual analog scale of pain rating. Temperature, blood pressure, heart rate, and respirations were monitored every 15 minutes.

Results: Both regimens performed well, with more than 90 percent of patients reporting good or excellent improvement on acute exacerbations of chronic pain. Ketorolac-chlorpromazine offered significant advantages compared with meperidine-promethazine when patients rated their pain on a visual analog pain scale (P < 0.05) but not on a verbal scale. Adverse reactions were minimal and consisted of more respiratory tract depression with meperidine and more vertigo or dizziness with chlorpromazine. There was no difference in incidence of hypotension between the two groups.

Conclusions: The combination of ketorolac and chlorpromazine is a safe and efficacious alternative to meperidine plus promethazine for the treatment of exacerbations of chronic pain in the rural emergency department setting.