A comparative study between hyperbaric prilocaine 2% versus hyperbaric bupivacaine 0.5% for intrathecal anesthesia in cesarean section

Bupivacaine has a variable block duration, while prilocaine provides a shorter, more predictable block but is less used in obstetrics. The goal is to compare the onset and duration of block induced by hyperbaric prilocaine 2% and hyperbaric bupivacaine 0.5% in intrathecal anesthesia for women undergoing elective cesarean sections (CS).

A prospective randomized and double-blind clinical trial included 144 individuals with uncomplicated pregnancies belonging to the American Society of Anesthesiologists physical status I or II. Patients were divided into two equal groups randomly: prilocaine group (Group A): received 60 mg hyperbaric prilocaine 2% (3 ml) intrathecally, and bupivacaine group (Group B): received 12.5 mg hyperbaric bupivacaine 0.5% (2.5 ml) intrathecally and 0.5 ml of normal saline. As 60 mg hyperbaric prilocaine 2% is equipotent to 12.5 mg of hyperbaric bupivacaine 0.5%. Onset time and duration of sensory and motor block recorded.

Mean arterial blood pressure was higher in Group A than in Group B at 5, 10, 15, and 20 min (P < 0.001), with no differences at baseline or 25-45 min. Intraoperative heart rate was substantially higher in Group B at 5, 10, 15, and 20 min, with comparable values at other time points. Visual analog scale (VAS) scores were higher in Group A at 1 h (P < 0.001) but substantially lower at 2 and 3 h (P < 0.001); VAS scores at 4 h were similar between groups.

Hyperbaric prilocaine 2% provides faster onset, shorter sensory and motor block duration, more stable hemodynamics and less maternal hypotension than hyperbaric bupivacaine 0.5% in CS, with similar neonatal outcomes and side effects.