• José Francisco Nunes Pereira das Neves, Giovani Alves Monteiro, João Rosa de Almeida, Roberto Silva Sant'anna, Rodrigo Machado Saldanha, José Mariano Soares de Moraes, Emerson Salim Nogueira, Fernando Lima Coutinho, Mariana Moraes Pereira das Neves, Fernando Paiva Araújo, and Paula Brazilio Nóbrega.
• CET/SBA, UFJF.
• Rev Bras Anestesiol. 2006 Aug 1; 56 (4): 370-6.

Background And ObjectivesThe mechanism of action of alpha2-adrenergic analgesia has been explored for more than one hundred years. The increased duration of the sensitive and motor blockades caused by clonidine is dose-dependent and has antinociceptive properties. The objective of this study was to evaluate whether the addition of 15 to 30 microg of clonidine to spinal anesthesia for cesarean sections with 0.5% hyperbaric bupivacaine (12.5 mg) and morphine (100 microg) improves the quality of postoperative analgesia.MethodsWe realized a prospective, randomized study that included 60 patients divided in 3 groups: BM - 0.5% hyperbaric bupivacaine (12.5 mg) and morphine (100 microg), BM15 - 0.5% hyperbaric bupivacaine (12.5 mg), morphine (100 microg), and clonidine (15 mg), and BM30 - 0.5% hyperbaric bupivacaine (12.5 mg), morphine (100 microg), and clonidine (30 microg), administered separately. In the perioperative period the use of ephedrine and the newborn's Apgar score were recorded. In the postoperative period, the pain was evaluated in the 12th h by the VAS, the length of time it took the patient to ask for analgesics, and the postoperative side effects, such as pruritus, nausea, vomiting, bradycardia, hypotension, and sedation. The values were considered significant when p < 0.05.ResultsThe groups were homogenous. The use of ephedrine and the evaluation by the Apgar score did not show statistically significant differences among the different groups. The pain scores and the average time to start analgesia showed differences among the groups BM and BM15/BM30, and there were no differences regarding the incidence of postoperative side effects.ConclusionsThe addition of clonidine to spinal anesthesia with 0.5% hyperbaric bupivacaine (12.5 mg) and morphine (100 microg) for cesarean section improved the quality of the postoperative analgesia without increasing the incidence of side effects. We suggest that the dose of 15 microg of clonidine should be used.

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