Isopropyl alcohol inhalation versus 5-HT(3) antagonists for treatment of nausea: a meta-analysis of randomised controlled trials

PURPOSE: Nausea is a common and unpleasant sensation for which current therapies such as serotonin (5-HT(3)) antagonists are often ineffective, while also conferring a risk of potential adverse events. Isopropyl alcohol (IPA) has been proposed as a treatment for nausea. We aimed to compare IPA with 5-HT(3) antagonists for the treatment of nausea across all clinical settings. METHODS: MEDLINE, EMBASE, PubMed, CENTRAL and CINAHL were searched from inception to 17 July 2023 for randomised controlled trials (RCTs) comparing inhaled IPA and a 5-HT(3) antagonist for treatment of nausea. Severity and duration of nausea, rescue antiemetic use, adverse events and patient satisfaction were the outcomes sought. Risk of bias (RoB) was assessed using Cochrane RoB 2. Random-effects model was used for meta-analysis. Combination of meta-analyses and narrative review was used to synthesise findings. The evidence was appraised using GRADE. RESULTS: From 1242 records, 4 RCTs were included with 382 participants. Participants receiving IPA had a significantly lower mean time to 50% reduction in nausea (MD − 20.06; 95% CI − 26.26, − 13.85). Nausea score reduction at 30 min was significantly greater in the IPA group (MD 21.47; 95% CI 15.47, 27.47). IPA led to significantly reduced requirement for rescue antiemetics (OR 0.60; 95% CI 0.37, 0.95; p = 0.03). IPA led to no significant difference in patient satisfaction when compared with a 5-HT(3) antagonist. The overall GRADE assessment of evidence quality ranged from very low to low. CONCLUSION: IPA may provide rapid, effective relief of nausea when compared with 5-HT(3) antagonists. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00228-023-03560-x.