Intravenous famotidine does not always change core temperature during general anesthesia

It has been reported that oral premedication with the H₂ receptor antagonist famotidine augmented intraoperative hypothermia. We again investigated whether the H₂ receptor antagonist famotidine significantly affected body temperature during open abdominal surgery under general anesthesia. We studied 20 female patients undergoing elective gynecological surgery. Participating patients were assigned randomly to one of two regimens: (1) 10 ml saline given intravenously just before induction of general anesthesia or (2) 20 mg famotidine in 10 ml saline given just before induction of general anesthesia. General anesthesia was induced by 2 mg·kg⁻¹ propofol and 0.1 mg·kg⁻¹ vecuronium. After tracheal intubation, anesthesia was maintained with sevoflurane (1%–2%) in nitrous oxide (2 l·min⁻¹) and oxygen (1 l·min⁻¹) along with 1–2 μg·kg⁻¹ fentanyl as needed. Tympanic temperature (T_Tym) was measured as the core temperature, and arteriovenous perfusion of the fingertip was evaluated using the forearmminus-fingertip skin-surface temperature gradient (Grad_a–f). T_Tym gradually and significantly decreased in both groups during anesthesia, and no significant differences in these values were observed between the two groups. Grad_a–f did not differ significantly between the two groups during anesthesia. We conclude that intravenous famotidine does not always change the core temperature during general anesthesia.