The Efficacy of Pregabalin on the Duration of the Spinal Anesthesia and the Early Postoperative Pain After Total Knee Arthroplasty

Inclusion Criteria: * the ages of 40 and 70 years * height 155-170 cm * American Society of Anesthesiologists grade I or II . * patients underwent total knee arthroplasty under spinal anesthesia Exclusion Criteria: * patients known to be allergic to any medicines. * patients had a history of drug or alcohol abuse. * patients were taking opioids or sedative medications, * patients Inability to communicate with investigators to evaluate the postoperative pain * patients were in need for postoperative ICU hospitalization . * patients had a history of psychiatric conditions. * Patients with a history of taking pregabalin or gabapentin .