Dementia refers to a decline in thinking, learning, memory and social skills severe enough to interfere with everyday activities. Dementia has many causes including Alzheimer's disease, vascular dementia, Lewy body dementia, frontotemporal dementia and dementia due to underlying medical conditions or treatments. The exact cause of dementia will determine the best medication for treating the symptoms.
Memantine
Memantine, an NMDA (N-methyl-D-aspartate) antagonist, works by blocking the excessive action of a stimulant neurotransmitter called glutamate. Overstimulation of neurons by glutamate can cause cell death, leading to impaired cognitive function and memory. Doctors commonly prescribe memantine to treat mild to moderate Alzheimer's disease. Memantine can slow the progress of Alzheimer's disease and can also improve memory and intellectual function in patients with other types of dementia, according to the Merck Manual.
Cholinesterase Inhibitors
Cholinesterase inhibitors increase the availability of the neurotransmitter acetylcholine, which plays a critical role in judgment and memory. According to the National Institute of Neurological Disorders and Stroke, the hippocampus and cerebral cortex, brain areas damaged in Alzheimer's disease, use acetylcholine in the formation of memories.
The cholinesterase inhibitors can slow the progress of Alzheimer's disease, the Mayo Clinic reports. Like memantine, cholinesterase inhibitors are useful for other types of dementia, in particular Lewy body dementia and vascular dementia. The cholinesterase inhibitor donezepil has a low incidence of side effects so it is commonly prescribed. Other possibilities include galantamine, which might be best to control behavioral issues; rivastigmine, and tacrine, seldom prescribed because it can damage the liver.
Memantine and cholinesterase inhibitors affect two different brain systems, and taking both types of drugs together can control dementia better than either type alone. The National Institute of Neurological Disorders and Stroke says that a large clinical study found that patients who took donezepil and memantine had better outcomes than patients who took donezepil alone.
Other Medications
In addition to cholinesterase inhibitors and memantine, medications that control blood pressure and cholesterol levels can benefit patients with vascular dementia. According to the Mayo Clinic, vascular dementia often occurs after a heart attack or stroke because of brain damage induced by a lack of adequate blood supply. Medications that control blood pressure and cholesterol levels improve blood flow to the brain and prevent further damage.
For other medical causes of dementia, often treating the underlying defect might suffice to cure the dementia. For instance, infections, immune disorders, metabolic or endocrine malfunctions all can cause dementia, and treating the condition often reverses the dementia without the use of any specific medications for the cognitive symptoms.
