Pharmacological Comparison of Ketamine and Tramadol for Prevention of Shivering During Spinal Anesthesia

Background: Shivering is a frequent and uncomfortable complication following spinal anesthesia, contributing to increased metabolic demand, hemodynamic stress, and patient dissatisfaction. While both ketamine and tramadol are pharmacologic agents used to prevent this response, comparative data on their efficacy and safety remain inconclusive. Objective: This study aimed to compare the effectiveness and side effect profiles of intravenous ketamine (0.5 mg/kg) and tramadol (1 mg/kg) in preventing post-spinal anesthesia shivering, with the expectation that tramadol would offer superior tolerability and efficacy. Methods: A randomized controlled trial was conducted on 60 adult patients (n = 60) undergoing elective surgery under spinal anesthesia at Mayo Hospital, Lahore. Inclusion criteria were adults aged 18–65 years with ASA I or II status, while patients with hypersensitivity, psychiatric illness, seizures, or baseline hypothermia were excluded. Participants were randomly assigned to ketamine or tramadol groups. Shivering was assessed using the Bedside Shivering Assessment Scale, and adverse effects were monitored. Ethical approval was obtained from the Institutional Review Board of Superior University, in accordance with the Declaration of Helsinki. Data were analyzed using SPSS v27.0; chi-square and descriptive statistics were applied. Results: Tramadol reduced the incidence of shivering to 10% compared to 20% in the ketamine group (p = 0.30). No severe shivering occurred in the tramadol group, and fewer neuropsychiatric side effects were reported (hallucinations: 0% vs. 6.7%). Conclusion: Both agents were effective, but tramadol demonstrated a better safety profile and higher clinical acceptability. These findings support its preferential use in shivering management during spinal anesthesia and warrant broader adoption in routine anesthetic protocols