There are several drugs, which are used in treatment (management) of Alzheimer’s disease (AD), some of which are approved and some are not approved by appropriate authorities (such as USFDA) for treatment of Alzheimer’s disease. All of the drugs used in Alzheimer’s disease acts non-specifically and that is the reason so many drugs are available and used in the treatment of AD. Some drugs are shown to have beneficial effects on the disease and used for management.

At present USFDA approves donepezil, rivastigmine, galantamine, memantine, and tacrine for treatment of Alzheimer’s disease. But tacrine is highly hepatotoxic (toxic to liver) and no more used for management of Alzheimer’s disease. Donepezil, rivastigmine and galantamine acts by cholinesterase inhibiting the enzyme cholinesterase (the enzyme is responsible for breakdown or metabolism of acetylcholine), which results increase in acetylcholine in brain. Memantine act by blocking overexcited N-methyl-D-aspartate (NMDA) channels.

Studies (double-blind, placebo-controlled, crossover studies) with memantine and cholinesterase inhibitors (donepezil, rivastigmine, galantamine) has shown to improve cognitive function and the caregiver’s rating for patients functioning. The maintenance of cognitive test score is better for patients using cholinesterase inhibitors, than those using placebo. Use of cholinesterase inhibitors and memantine also slow down the cognitive deterioration in moderate to severe AD, but they are not approved for use in mild AD patients.

The side effects of cholinesterase inhibitors are not severe and include sleep disturbance, lowering of heart rate, muscle cramps, gastrointestinal symptoms such as nausea, diarrhea, and cramps.

How other medications (such as gingko biloba, NSAIDs, antioxidants, lipid lowering agent statins) used in Alzheimer’s disease acts is not clear.