Statin‑associated myasthenia gravis: a real-world retrospective and pharmacovigilance study

Myasthenia gravis (MG) is a rare but serious adverse event (AE) of statins. Yet, its pharmacovigilance and clinical features remain unknown.

Data were extracted from the FDA Adverse Event Reporting System (FAERS) (2004 Q1-2023 Q4), and disproportionality analyses were conducted. Case reports on statin-associated MG dated up to 31 December 2023 were retrieved for retrospective analysis.

Data from FAERS showed 178,802 AEs of statins, with musculoskeletal disorders being the most common. Compared to other cholesterol-lowering drugs, statins exhibited a significant increase in MG, with 128 reports included, with pravastatin having the highest proportion. Sixteen cases from 12 studies demonstrated atorvastatin was the most frequently reported agent associated with MG. The median age was 58 years, with a male predominance. The main clinical symptoms were ocular muscle weakness, lasting from 1 week to 3 years. Twelve patients were acetylcholine receptor (AChR) antibody positive. All patients discontinued statins, 14 patients received treatment comprising cholinesterase inhibitors and immunosuppressive drugs. Nine patients achieved recovery, and five patients relapsed after steroid reduction or statins re-administration.

In the real-world pharmacovigilance study, statins are associated with increased reporting of MG. Early identification and timely treatment are crucial for the safe use of statins.