Introduction:

The main adjuvants of bupivacaine are opioids and clonidine; the first opioid used by the epidural route was morphine, which since 1979 has demonstrated benefit of its intrathecal and extradural use, for the management of chronic and postoperative pain.

Objective:

Determine the analgesic effectiveness of morphine vs. clonidine added to spinal anesthesia with hyperbaric bupivacaine in patients undergoing cesarean section.

Method:

A quasi-experimental correlational clinical trial. 60 parturients, carrying a singleton fetus at term, scheduled to undergo cesarean section under spinal anesthesia were randomized in one of the two groups. Group BC (n = 30) received 10 mg hyperbaric bupivacaine and 75 μg clonidine; Group BM (n = 30) 10 mg hyperbaric bupivacaine and 100 μg morphine.

Results:

Statistically significant difference, p = 0.02, were found between the time of 14.5 ± 2.1 hours since the administration of anesthesia to the application of the first dose of additional analgesia in morphine group vs. clonidine group 8.18 ± 2.91 hours. Pain at the time of the application of postoperative analgesia was superior in clonidine group with 6.4 ± 1.0 points in AVE vs. morphine with 0.93 ± 2.4 points. p = 0.001. AVE values were also significantly higher for clonidine in relation to morphine at 6, 12 and 18 hours. No significant hemodynamic and respiratory changes occurred in either group. For morphine the most frequent side effect was itching in 66.7 % of patients. The level of sedation was the same for clonidine and morphine in all the patients.

Conclusions:

Add 100 μg of morphine to hyperbaric bupivacaine for spinal anesthesia prolongs the time and significantly improves quality of the postoperative analgesic period greater than 75 μg of clonidine. The most common side effect is itching.

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