Inclusion Criteria:  ASA physical status classes I and II Scheduled for elective cesarean section Aged between 20-45 years .  Exclusion Criteria:  patient refusal. patient with significant cardiovascular disease , hepatic dysfunction , renal failure , chronic pulmonary disease . neuromuscular disorder. infection. bleeding disorder. Obesity ( BMI > 30 kg/m2 ) . History of allergy or sensitivity to any of the study drugs in previous surgeries .