Alzheimer's disease is a progressive and fatal condition affecting the brain--a disease for which there is no cure. Fisher Center For Alzheimer's Research Foundation states that the FDA currently has five drugs approved to help relieve the symptoms of this disease. The Mayo Clinic adds that these medications don't work for everyone, and that the most common are effective in half the people who use them.
Tacrine (Cognex)
Approved by the FDA in 1993, according to the Fisher Center for Alzheimer's Research Foundation, tacrine helps to slow the progression of Alzheimer's in its early stages. Available in 10, 20, 30 and 40 mg capsules, the benefits of tacrine are modest at best, effective in approximately one-third of those taking it. The side effects of this drug are severe, however, and include seizures, liver damage, severe vomiting and racing heartbeat. For these reasons this medication is rarely given today.
Donepezil (Aricept)
Donepezil is one of the most commonly prescribed cholinesterase inhibitors, a class of drugs that work by increasing the levels of a chemical known as acetylcholine. This chemical, according to the Mayo Clinic, is believed to play an important role in memory, thought and judgment. Those with Alzheimer's have lower levels of this chemical. When the medications do not increase the levels of acetylcholine, they enhance the nerve cells' response to it.
Donepezil, approved in 1996, is available in either 5 or 10 mg tablets, and helps those with mild to moderate Alzheimer's. The Fisher Center for Alzheimer's Research Foundation states that this drug, in some studies, was beneficial in up to 80 percent of patients taking it.
This medication is typically taken at bedtime, and its most common side effects include nausea, vomiting and diarrhea, all of which tend to subside within one to three weeks.
Rivastigmine (Exelon)
Another cholinesterase inhibitor, rivastigmine, was approved in 2000 and comes in 1.5, 3, 4.5 and 6 mg capsules. Designed to treat the symptoms of early Alzheimer's, half of those patients with mild to moderate symptoms seem to show a slight improvement in their condition.
The Mayo Clinic states that this drug may cause more severe gastrointestinal problems than other medications in its class; this includes possible bleeding in the stomach or bowel. To combat this, doctors usually begin the patient with a small dose, gradually working up to a higher dose as the body adjusts. Taking riastigmine with food may also help, as can the new adhesive patch in which it is available.
Memantine (Namenda)
The newest medication to join the fight against Alzheimer's, memantine, received its approval in 2003. This drug differs from the rest in that it is the first designed for those with moderate to severe Alzheimer's. Its purpose is also different, as it regulates the chemical messenger, glutamate. This chemical works on all brain function, including learning and memory, according to the Mayo Clinic.
Available in 10 mg capsules, the Fisher Center for Alzheimer's Research Foundation states that patients deteriorated only half as much as they would have if they had not been taking the medication.
The most common side effects include dizziness, constipation, headache and skin rash. No serious side effects are currently reported.
