Respiratory and circulatory effects of pentazocine: Review of analgesics used after myocardial infarction

Abstract

The analgesic pentazocine has been studied in myocardial infarction. A dose of 30 mg given intravenously provokes significant respiratory depression (which may be potentiated by Ugno-caine). This dose caused a small, but not significant rise in systemic arterial pressure and heart rate when breathing air. Attempts to provoke postural hypotension failed. Changes in pulmonary arterial pressure and arteriovenous oxygen difference were small and not significant. The published reports have been reviewed with a view to determining the most suitable intravenous analgesic for use after myocardial infarction. Pethidine and morphine appear to be unsatisfactory. Pentazocine is preferable to either, but less satisfactory than heroin in a normotensive patient. Dosage should be as small as practicable and injection slow. Oxygen should be given routinely; phenothiazines should not.