Abnormal posture of the trunk related to donepezil hydrochloride: report of 2 cases

Abstract

Patient 1, an 80-year-old woman with Alzheimer's disease, had been taking donepezil 5mg for 2 years. Donepezil was increased to 10mg, and 2 months later, the patient developed dropped head syndrome. MRI and needle EMG abnormality of the neck extensor muscles suggested focal myopathy, but the symptom disappeared within 2 months by discontinuing donepezil. Patient 2, a 78-year-old man with Lewy body dementia, had been taking levodopa and pramipexole (PPX). One month after tapering levodopa, donepezil 3mg was introduced, and Pisa syndrome (bending of the trunk to the right anterior direction) developed 10 days later. Donepezil and PPX were discontinued and levodopa was increased. Within 5 months, his posture had almost recovered. Cholinesterase inhibitors can induce abnormal posture of the trunk, and clinicians should be aware of this uncommon but important side effect.