Indication: Mild to moderately severe dementia of the Alzheimer type, but also can be helpful in other neurodegenerative disorders and sometimes benefit in traumatic brain injury and other acquired brain injury cases.

Dosage: 5 mg daily is the recommended starting dose. If well tolerated, it may be increased after a minimum of 2 weeks of treatment to 5 mg twice daily, or 10 mg in the morning, up to a maximum of 20 mg daily, usually in divided doses. Adverse effects may respond to omitting one or more doses. If they persist, the daily dose should be reduced to the previous well ­tolerated dose.

Contraindications: Known hypersensitivity to donepezil, other carbamate derivatives, or other ingredients of the capsules. Severe liver impairment since it has not been studied in this population.

Precautions/Warnings: As with other cholinomimetics, caution is recommended in patients with sick sinus syndrome, conduction defects (sino-atrial block, atrio-ventricular block), gastroduodenal ulcerative conditions in predisposed patients, history of or current respiratory disease, urinary obstruction, and seizures. 

Interactions: Cholinomimetic drugs, anticholinergic medications, succinylcholine-type muscle relaxants during anaesthesia. Bradycardia may develop if taken alongside beta blockers, amiodarone, alcium channel blockers or digoxin. The effect of benztropine, oxybutinin etc may be antagonised.

Possible adverse reactions: Nausea, vomiting, diarrhoea, abdominal pain, loss of appetite, dyspepsia, dizziness, fatigue, headache. Rarely, angina pectoris, gastric and duodenal ulcers, gastrointestinal haemorrhage, bradycardia, seizures, rashes, and syncope.