A comparison of the analgesic effects of profadol and morphine in patients with cancer

The relative analgesic potency of profadol (CI‐572) and morphine was evaluated in a double‐blind crossover comparison of graded, single intramuscular doses in patients with chronic pain due to cancer. Profadol was found to be about one fourth as potent as morphine. The time‐effect curves of the 2 drugs were similar. Profadol produced more injection‐site pain than morphine, but other effects observed after the 2 drugs were similar in kind and occurrence.