Common Side Effects of Relyvrio
Relyvrio (sodium phenylbutyrate/taurursodiol), approved for ALS in 2022, causes diarrhea in 42% of patients, abdominal pain in 26%, nausea in 23%, and upper respiratory tract infection in 20%. Other frequent issues include headache (17%), muscle spasms (16%), falls (15%), and back pain (14%). These occurred more often than with placebo in clinical trials.[1][2]
Serious Side Effects and Warnings
Serious risks include pancreatitis (report severe abdominal pain), changes in liver tests (monitor enzymes), and severe diarrhea. The drug carries a boxed warning for potential liver injury. Discontinue if pancreatitis develops. Avoid in patients with known liver disease or bile duct issues.[1][2][3]
Side Effects in Clinical Trials
In the CENTAUR trial (112 patients), gastrointestinal effects dominated: salivation (13%), constipation (12%), and vomiting (11%). Neurological effects like dizziness (12%) also appeared. Long-term data from extended trials showed similar patterns, with 20% of patients stopping due to adverse events vs. 12% on placebo.[2][4]
What Patients Report vs. Trial Data
Real-world use via expanded access (similar profile) and post-marketing reports highlight persistent diarrhea and nausea, sometimes leading to dehydration. Some patients note fatigue or worsened ALS symptoms, though not causally linked. FDA reviews emphasize monitoring for cumulative liver effects over time.[3][5]
How to Manage Relyvrio Side Effects
Take with food to reduce GI upset. Stay hydrated for diarrhea. Regular blood tests check liver function monthly for first 3 months, then periodically. Dose adjustments or discontinuation may be needed. Consult a doctor before starting; not recommended in pregnancy.[1][2]
Comparisons to Other ALS Drugs
Unlike Riluzole (nausea, liver issues) or Edaravone (gait issues, headaches), Relyvrio's profile skews heavily GI-focused. Trials showed higher dropout rates from side effects than Riluzole but similar tolerability to Edaravone.4
[1]: https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/217270s000lbl.pdf
[2]: https://www.alsnewstoday.com/relyvrio/
[3]: https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/tauvursodiol-and-sodium-phenylbutyrate-marketed-relyvrio-information
[4]: Lancet Neurol. 2020;19(10):865-875 (CENTAUR trial)
[5]: https://www.als.org/navigating-als/living-with-als/medications/relyvrio