Effect of Preoperative Oral Pregabalin Versus Intraoperative Fentanyl on Postoperative Analgesia

Pregabalin is a structural analogue of gamma amino butyric acid (GABA). It binds to presynaptic alpha-2-delta subunit of voltage gated calcium channels in the brain and the spinal cord. Thus, it modulates the release of excitatory neurotransmitters, such as glutamate, norepinephrine, substance-P, and calcitonin gene related peptide. Also, it causes inhibitory modulation of overexcited neurons and restores them to a normal state. Pre-emptive analgesia aims to reduce postoperative opioid consumption especially in ambulatory surgeries. Pregabalin (PGB) is an emerging drug in this field. Different doses of preoperative oral pregabalin (75, 150 and 300 mg) are described in the literature with a dose-response analgesic relationship and reduction of opioid use; however increasing the dose results in increasing the incidence of side effects mainly sedation and dizziness. Perioperative use of opioids for analgesia may result in side effects; like nausea, vomiting, excessive sedation, respiratory depression, pruritus, and urinary retention.The concomitant use of opioids with pregabalin may result in excess sedation and somnolence, so, the use of opioids with pregabalin should be limited to patients with inadequate alternative options.