Belsomra Does Not Cause Elevated Liver Enzymes
Based on FDA labeling and clinical trial data, Belsomra (suvorexant) is not associated with elevated liver enzymes and does not require routine liver function monitoring. 1
Evidence from FDA Drug Labeling
The FDA prescribing information for Belsomra does not list hepatotoxicity or elevated liver enzymes as a known adverse effect 1. The documented adverse effects include:
- Somnolence (most common specific adverse effect at 7% vs 3% placebo)
- Cognitive and behavioral changes (amnesia, anxiety, hallucinations)
- Complex sleep behaviors
- Sleep paralysis
- Daytime impairment
Clinical Trial Safety Data
In controlled trials involving 2,811 patients across studies lasting 3 months to 1 year, no hepatic adverse effects were reported 2. The FDA medical reviews specifically noted few serious adverse effects overall, and none were more common than placebo at approved doses (20 mg for non-elderly, 15 mg for elderly patients) 2.
Hepatic Impairment Considerations
Importantly, the FDA labeling addresses use in patients with existing liver disease 1:
- No dose adjustment needed for mild to moderate hepatic impairment
- The drug has not been studied in severe hepatic impairment and is not recommended in this population
- In patients with moderate hepatic insufficiency, the half-life increases from ~15 hours to ~19 hours, but exposure remains similar
Animal Toxicology Note
While hepatocellular adenomas were observed in male rats at very high doses (325 mg/kg/day) in 2-year carcinogenicity studies, this occurred via hepatic enzyme induction—a rodent-specific mechanism not considered clinically relevant to humans 1. This finding does not translate to liver enzyme elevation in clinical use.
Clinical Bottom Line
You do not need to monitor liver enzymes when prescribing Belsomra. If a patient on Belsomra develops elevated liver enzymes, investigate other causes rather than attributing it to the medication. The drug's safety profile centers on CNS effects (somnolence, falls risk in elderly) rather than hepatic toxicity.