Donepezil - Alzheimer's Medication Information

Donepezil is a centrally acting reversible acetylcholinesterase inhibitor. It is marketed under the trade name Aricept by its developers Eisai and Pfizer. Its primary use is in the treatment of Alzheimer's disease where it is used to increase cortical acetylcholine. It easily crosses the blood-brain barrier and has an oral bio-availability of 100%. Since it has a half life of about 70 hours, it can be taken once a day. The initial dose is 5 mg per day, which can be increased to 10 mg per day after an adjustment period of at least one month. There is no definitive proof that use of donepezil alters the course or progression of Alzheimer's disease. However, six different 12 month controlled studies have shown some benefits in cognition and/or behavior. Pilot studies have also reported that donepezil therapy may have effects on hippocampal volume and other markers of disease progression. Therefore, many neurologists, psychiatrists, and primary care physicians use donepezil in patients with Alzheimer's disease. The drug is indicated for mild to moderate Alzheimer's, but there is evidence from 2 trials that it may be effective for moderate to severe disease as well.

Indications

Donepezil has been tested in other cognitive disorders such as vascular dementia and Lewy body dementia, but it is not currently approved for these indications. Donepezil has also been found to improved sleep apnea in some Alzheimer's patients.

Donepezil has been studied in patients with attention deficit disorder, mild cognitive impairment, schizophrenia, cognitive impairment associated with multiple sclerosis, post-coronary bypass cognitive impairment, and Down syndrome. Recent studies have suggested that donepezil can improve speech in children with autism. The studies found that speech of austistic children who were mild to moderately affected appeared to improve from the use of the drug.

Donepezil is known to improve the function of nerve cells in the brain. It works by preventing the breakdown of the chemical acetylcholine. Sufferers of dementia generally have lower levels of this chemical, which is a key factor in the processes of memory, thinking, and reasoning.

Do not take this medication if you are allergic to it. Before taking donepezil, tell your doctor if you are allergic to any drugs, or if you have a heart rhythm disorder, a history of stomach ulcers, an enlarged prostate or urination problems, epilepsy or other seizure disorder, or if you have asthma or chronic obstructive pulmonary disease. If you have any of these conditions, you may need a dose adjustment or special tests to safely take donepezil.

This medication may be harmful to an unborn baby. It is important to tell your doctor if you are pregnant or plan to become pregnant during treatment. It is unknown whether the drug passes into breast milk or if it could harm a nursing baby. If you are breast-feeding a baby, do not use this medication without first telling your doctor. This medication should be taken exactly as it is prescribed. Do not take the medication in larger amounts than prescribed, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.

Side Effects

Common side effects include bradycardia, nausea, diarrhea, anorexia, abdominal pain, and vivid dreams.

Be sure to get emergency medical help if you have any of these signs of an allergic reaction: difficulty breathing; hives; swelling of the face, tongue, lips, or throat. Stop using donepezil and call your doctor at once if you have any serious side effects including painful or difficult urination, seizure, black, bloody, or tarry stools, or if you cough up blood or vomit that looks like blood or coffee grounds.

Less serious side effects may include muscle cramps, loss of appetite, insomnia, feeling tired, nausea, vomiting or diarrhea.