Statin-Induced Diplopia: A Rare Side Effect

Statin is one of the most effective medication to date in treating dyslipidemia. Moreover, statin is the most available in health clinics due to its cost-effectiveness. However, statin must be used with caution due to its severe rare side effects. Ocular disorder secondary to statin is rarely reported. In this case, statin-induced lateral gaze diplopia, worst on the left lateral gaze, was noted in a middle-aged Malay man. He had underlying dyslipidemia and was started on simvastatin 20mg at night three days before developing diplopia. He was otherwise well and had no other medical illnesses. There were no other neurological signs and abnormal ocular signs. Investigations were done and revealed no other abnormalities. The patient's symptom resolved gradually over eight weeks after discontinuation of the statin. Thus, this case highlights the important key point of anticipating this severe rare side effect of statin, which may be irreversible.