Efficacy & dose-response of intrathecal pentazocine for post-operative pain relief

With a view to assess the efficacy of intrathecal pentazocine for post-operative pain relief, 60 patients randomly divided into 6 equal groups were administered graded doses (0, 1, 2, 3, 4 and 5 mg respectively) of pentazocine lactate, intrathecally along with 1 per cent bupivacaine. The duration of analgesia was found to be dose related till 3 mg. Higher doses did not increase the duration of analgesia nor were any untoward effects observed. It is concluded that intrathecal pentazocine is safe and effective for post-operative pain relief and 3 mg is the minimum effective dose without side effect.