Analgesic and antacid properties of i.m. tramadol given before Caesarean section under general anaesthesia

Background. Intramuscular (i.m.) tramadol increases gastricpH during anaesthesia similar to famotidine. We investigatedthe antacid analgesic value of a single dose of i.m. tramadolgiven 1 h before elective Caesarean section performed undergeneral anaesthesia. Methods. Sixty ASA I parturients undergoing elective Caesareansection were included in a randomized double-blind study. Thepatients were randomly allocated to receive i.m. tramadol 100mg (n=30) or famotidine 20 mg (n=30) 1 h before general anaesthesia. Results. At the beginning and the end of anaesthesia, patientsreceiving tramadol had a median gastric fluid pH of 6.4, whichwas not significantly different from those treated with famotidine(median 6.3). The infant well-being, as judged by Apgar score,cord blood gas analysis, and neurobehavioural assessment showedno significant difference between the two groups. Nalbuphineconsumption in the first 24 h after operation was reduced by35% in the tramadol group. Pain intensity score on sitting andsedation were significantly greater in famotidine group up to24 h after surgery. There was no significant difference in incidenceand severity of nausea and vomiting between the two groups. Conclusion. A single i.m. dose of tramadol is useful pre-treatmentto minimize the risk of acid aspiration during operation, andin improving pain relief during 24 h after surgery.