Preemptive prophylactic intravenous granisetron reduces the incidence and severity of intrathecal fentanyl-induced pruritus

ABSTRACT

Pruritus is a common adverse event of intrathecal fentanyl for postoperative analgesia. Activation of central 5-hydroxytryptamine subtype[3] [5-HT [3]] receptors is one of its possible mechanisms. This randomized, double-blind, placebo-controlled study aimed at evaluating the effectiveness of granisetron for the prevention of intrathecal fentanyl-induced pruritus in patients undergoing gynecologic, urologic, orthopedic and general surgery. 120 parturients [American Society of Anesthesiologists [ASA] I-II status] undergoing surgery under spinal anesthesia using 15 mg hyperbaric bupivacaine [0.5%] and 25 micro g fentanyl were randomly divided to three equal groups [n=40]. Thirty minutes before spinal anesthesia, patients received granisetron 1 mg IV [GRN], granisetron 1 mg plus 8 mg dexamethasone IV [GRN/DEX], or normal saline IV [Placebo]. Pruritus, pain, sedation, nausea and vomiting scores were evaluated during the initial 24 hours postoperatively. The incidence of pruritus was significantly more frequent in Placebo group compared with GRN and GRN/DEX groups [75% versus 50% and 45%] [P pruritus was mostly mild to moderate. Duration of pruritus was similar in investigated groups but shorter in relation to placebo [GRN 117 +/- 65 min, GRN/DEX 108 +/- 59 min, versus Placebo group 195 +/- 106 min]. The onset time of pruritus in the GRN and GRN/DEX groups are significantly delayed [250 +/- 81 mm and 280 +/- 98 min] compared with Placebo group [75 +/- 25 min] [P<0.01]. Antipruritic agent was required by 25%, 15% and 50% in GRN, GRN/DEX and Placebo groups respectively. The incidence of postoperative nausea and vomiting was 35%, 25% and 65% in GRN, GRN/DEX and Placebo groups respectively. The prophylactic use of granisetron significantly reduces the incidence and severity of intrathecal fentanyl-induced pruritus in patients undergoing surgery under bupivacaine-fentanyl spinal anesthesia. Furthermore, the patients reported less post-operative nausea and vomiting in the granisetron group and combined granisetron/dexamethasone group than in the placebo group [P<0.01]