Inclusion Criteria:  adult female patients below 65 years of age scheduled for modified radical mastectomy surgery, American society of Anesthesiologists(ASA) physical status I-II  Exclusion Criteria:  known allergy to study drugs; patients already taking oral gabapentin, knal or hepatic defunction, current treatment with narcotics, antihypertensives, benzodiazepines, X2 agonists, antiepileptics and antipsychotics