[A case of myasthenia-like symptoms induced by cibenzoline overdosage].

The present patient was an 87-year-old man who had been taking cibenzoline for tachyarrhythmia. Five years after initiation of administration, he was referred to our hospital for ptosis that worsened from midday, as well as weakness of the facial and limb muscles. He tested negative for anti-acetylcholine receptor antibody but positive in the edrophonium test, suggesting that he had myasthenia gravis.