Indications: mild to moderate dementia in Alzheimer's disease.

Cautions: cardiac disease (including sick sinus syndrome or other supraventricular conduction abnormalities, unstable angina, congestive heart failure); electrolyte disturbances; susceptibility to peptic ulcers; asthma, chronic obstructive pulmonary disease, pulmonary infection; avoid in urinary retention, gastro-intestinal obstruction, and while recovering from bladder or gastro-intestinal surgery; history of seizures.

Hepatic impairment: for immediate-release preparations in moderate impairment, initially 4 mg once daily (preferably in the morning) for at least 7 days, then 4 mg twice daily for at least 4 weeks; max. 8 mg twice daily; avoid in severe impairment. for modified-release preparations in moderate impairment, initially 8 mg on alternate days (preferably in the morning) for 7 days, then 8 mg once daily for 4 weeks; max. 16 mg daily; avoid in severe impairment

Renal impairment: avoid if eGFR less than 9 ml/minute/1.73m2.

Pregnancy: use with caution

Side Effects: vomiting, nausea, abdominal pain, diarrhoea, dyspepsia, anorexia, weight loss, bradycardia, hypertension, syncope, hallucination, depression, dizziness, tremor, headache, drowsiness, malaise, muscle spasm, sweating; less commonly taste disturbance, palpitation, arrhythmias, first-degree AV block, hypotension, flushing, paraesthesia, dehydration, seizures, muscular weakness, blurred vision, tinnitus; rarely hepatitis, exacerbation of Parkinson’s disease.

Dose: Initially 4 mg twice daily for 4 weeks increased to 8 mg twice daily for 4 weeks.

Maintenance: 8-12 mg twice daily