Reactions 1228 - 15 Nov 2008

SAtorvastatin/pravastatin

Myasthenia gravis: case reportA 43-year-old man with hyperlipidaemia, who had

experienced a myocardial infarction (MI), developedmyasthenia gravis during treatment with atorvastatin. Hesubsequently experienced a recurrence of myasthenia gravisduring treatment with pravastatin [dosage not stated].

The man, who also had diabetes mellitus, developed diffusemyalgia soon after starting treatment withatorvastatin 10 mg/day. His myalgia worsened whenatorvastatin was subsequently increased to 20 mg/day, and hedeveloped bilateral blepharoptosis. One year later, followinganother MI, atorvastatin was increased to 40 mg/day. Two to 3weeks later, he experienced double vision and worseningblepharoptosis. Myasthenia gravis was suspected.

The man was treated with IV edrophonium and hisblepharoptosis improved. A subsequent investigation revealedan elevated acetylcholine receptor antibody (Anti-AchR) levelof 10.8 nmol/L, a titin level of 6.2 and an antibody titre againstparietal cells of 1024. Single fibre electromyography revealedincreased jitter and blocking in 24/30 pairs; the mean value ofthe consecutive differences was just above normal. Treatmentwith IV immunoglobulins, azathioprine, pyridostigmine andplasma exchange did not improve his condition. Atorvastatinwas considered a suspect 2 years after his first symptoms andthe agent was discontinued. His myalgia rapidly recoveredand, within a few days, his blepharoptosis had completelyresolved. He continued to experience diplopia. Repeat testsrevealed a normal Anti-AchR level 6 months afterdiscontinuing atorvastatin, but the AchR level remainedslightly elevated during the subsequent follow-up period.

The man experienced another MI 1 year after discontinuingatorvastatin. He was started on pravastatin and hisblepharoptosis soon recurred. Pravastatin was discontinuedand his blepharoptosis immediately improved. However, heexperienced a worsening of his blepharoptosis and diplopiawhen pravastatin was reintroduced. Pravastatin was againdiscontinued and he subsequently started treatment withezetimibe. He did not experience a recurrence of muscularcomplaints and his blepharoptosis resolved. His diplopiaremained remarkably stable and was surgically treated after2 years.

Author comment: "AchR antibody remained at a slightlyelevated level without statin, which could support a theorythat this patient had an underlying [myasthenia gravis]exacerbated by statin use. However, during a 3-yearobservation period after statin withdrawal, he revealed nomyasthenic symptom."Elsais A, et al. Ptosis, diplopia and statins: an association? European Journal ofNeurology 15: e92-e93, No. 10, Oct 2008 - Norway 801124594

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Reactions 15 Nov 2008 No. 12280114-9954/10/1228-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved