The only two drugs approved for AD, tacrine hydrochloride (Cognex) and donepezil hydrochloride (Aricept), increase the brain levels of the neurotransmitter acetylcholine, thereby increasing the communication ability of the remaining neurons. These drugs can modestly increase cognition and improve the ability to perform normal activities of daily living. The most significant side effect of tacrine is an increase in the liver enzyme alanine aminotransferase (ALT). Patients taking tacrine must have a weekly blood test to monitor their ALT levels. Other frequent side effects include nausea, vomiting, diarrhea, abdominal pain, indigestion, and skin rash. Donepezil has two advantages over tacrine: fewer side effects and once daily dosing. Donepezil does not appear to affect liver enzymes and the frequency of abdominal side effects is lower.
Estrogen, the female sex hormone, is widely prescribed for post-menopausal women to prevent osteoporosis. Several preliminary studies have shown that women taking estrogen have lower rates of AD, and those who develop AD have a slower progression and less severe symptoms.
Selegiline, a drug used in the treatment of Parkinson's disease, appears to slow the development of AD. Selegiline is thought to act as an antioxidant, preventing free radical damage. However, it also acts as a stimulant, making it difficult to determine whether the delay in onset of AD symptoms is due to protection from free radicals or to the general elevation of brain activity from the stimulant effect.
Psychiatric symptoms, such as depression, anxiety, hallucinations (seeing or hearing things that aren't there), and delusions (false beliefs) may be treated with drugs if necessary.
Belinda Rowland, Teresa G. Odle, The Gale Group Inc., Gale, Detroit,