Prevention of shivering post spinal anesthesia: Ondansetron vs. Nefopam ‒ a prospective randomized controlled trial

Post Spinal Anesthesia Shivering (PSAS) is common and linked to increased morbidity. While various methods exist to prevent it, no study has compared Nefopam and Ondansetron. This study aims to compare Ondansetron and Nefopam in preventing PSAS.

A prospective, randomized, controlled, and double-blind trial was conducted in the operating room of a tertiary university hospital from April 5, 2021 to April 30, 2022. It included patients aged between 18 and 65 years scheduled for surgery under spinal anesthesia. Patients received either 8 mg of Ondansetron or 20 mg of Nefopam administered intravenously over 30 min before spinal anesthesia. Main outcome measures included the number and grades of shivering episodes post spinal anesthesia at 15-minute intervals until post-anesthesia care unit discharge. Secondary outcomes included number of episodes of hypotension, bradycardia, nausea and/or vomiting. Tympanic temperature and pain at the injection site were also recorded.

The study included 150 patients, evenly divided between the two groups. The Ondansetron group had a higher incidence of shivering compared to the Nefopam group (23.9 % vs. 16 %; p = 0.038), as well as higher incidences of hypotension (16 % vs. 5.3 %; p = 0.035) and bradycardia (13.3 % vs. 2.7 %; p = 0.016). The Ondansetron group had a significantly lower incidence of nausea and vomiting (12 % vs. 1.3 %; p = 0.010). More patients in the Nefopam group (45.3 %) reported pain during drug infusion.

Nefopam seems to be more effective than Ondansetron in preventing PSAS with fewer cardiovascular side effects. However, Ondansetron reduces the incidence of nausea and vomiting and causes no pain during administration.