Galantamine hydrobromide: an agent for Alzheimer's disease.

The pharmacology, dosage, adverse effects, efficacy, and economics of galantamine hydrobromide are discussed. Galantamine hydrobromide is a tertiary alkaloid that has been extracted from plant sources and is now synthesized for use in the treatment of mild to moderate Alzheimer's disease (AD). Galantamine acts both as a reversible competitive inhibitor of acetylcholinesterase (AChE) and as an allosteric modulator of nicotinic acetylcholine receptors. The recommended starting dosage is 4 mg (as the hydrobromide) twice daily. The dosage should be increased in increments of 8 mg/day in two divided doses after four weeks at a given dosage until a maintenance dosage of 16-24 mg/day in two divided doses is reached. Adverse effects are primarily mild and cholinergic and include nausea, vomiting, diarrhea, and dizziness. Five large clinical trials demonstrated that galantamine is more effective than placebo in controlling the symptoms of mild to moderate AD. Optimal therapy appears to require early initiation of the drug and a dosage-adjustment period of eight weeks. In one study, galantamine delayed full-time care by 10% and reduced the overall cost of care by $528. Because galantamine has not yet been compared directly with other AChE inhibitors, cost should be the principal factor weighed during formulary evaluations. Galantamine provides the clinician with another choice of an AChE inhibitor for use in treating AD.