Serum Serotonin and Pruritus After Intrathecal Morphine in Cesarean Section

Pruritus After Intrathecal Morphine in Cesarean Section: Incidence, Severity and Its Relation to Serum Serotonin Level

Pruritus is the commonest side effect of intrathecal morphine especially in parturient, but the exact mechanism of pruritus is not clear. Many mechanisms have been suggested. Among these mechanisms is the activation of the 5-HT3 receptors by the intrathecally injected morphine.

Forty parturients underwent elective cesarean section under spinal anesthesia were divided into two groups of 20 each in this prospective randomized study. Group I received 100 µg of intrathecal morphine (ITM) mixed with 12 mg of 0.5% heavy bupivacaine (M100) while group II received 200 µg of ITM mixed with 12 mg of 0.5% heavy bupivacaine (M200). Two blood samples were taken from each patient for serotonin estimation, preoperatively and 4 hrs later. Postoperatively all patients were assessed for pruritus (incidence & severity), visual analog scale (VAS), first request of analgesia, and total analgesic dose required within 24 hrs.

Inclusion Criteria:

• ASA I - II term pregnant patients scheduled for elective cesarean section

Exclusion Criteria:

• patients with a known allergy to the study drugs
• significant cardiac, respiratory, renal, neurological, or hepatic disease; -coagulation disorders
• BMI > 30 kg/m2
• any itchy skin diseases.