An investigation of premedication with morphine given by the buccal or intramuscular route.

1. Premedication with 30 mg buccal morphine or 10 mg intramuscular morphine was evaluated in 40 healthy women undergoing major gynaecological surgery. 2. Buccal administration of morphine produced lower plasma morphine concentrations than intramuscular injection of morphine (P less than 0.01). 3. The mean systemic availability of the buccal tablet, during the first 5 h after administration, was approximately 3% relative to that of the intramuscular preparation. 4. Poor absorption of buccal morphine resulted in inadequate sedation prior to surgery and poor post-operative analgesia. 5. Patients experienced difficulty with the buccal formulation of morphine; tablet bitterness and failure to dissolve were particular problems.