Aricept® is the most popular medication for treating Alzheimer's dementia. It is also sometimes used to treat other dementias, although it has not received Food and Drug Agency (FDA) approval for any disorder other than Alzheimer's.
How Aricept Works
Aricept is an acetylcholine esterase inhibitor. That means it blocks the breakdown of acetylcholine, especially in the brain, but also elsewhere in the body. This tends to increase acetylcholine. Increased acetylcholine can be useful in the brain, since it is usually depleted in the brains of Alzheimer's dementia patients. (It is important to note that, "There is no evidence that [these medications] alter the underlying dementing process," according to Aricept's marketers. This means these medications do not slow down the relentless destruction of brain cells that occurs in Alzheimer's dementia. The intention of the therapy is to improve the symptoms.)
On the other hand, increasing acetylcholine in other parts of the body can cause disturbing and sometimes dangerous side effects.
Available Aricept Doses
Before the introduction in Spring, 2011 of the 23 mg dose, Aricept was available in North America in 5 mg and 10 mg doses. Aricept is a brand name for donepezil. In Spring, 2011, donepezil became available as a generic product in 5 mg and 10 mg doses, thus competing directly with the trade name product.
Public Citizen's Beef
Public Citizen is a not-for-profit organization that describes itself as "(T)he countervailing force to corporate power...(that fights) on behalf of all Americans—to make sure your government works for you."
They believe the FDA, a government agency, should not have approved the new 23 mg dose of Aricept. Without FDA approval, that dose cannot be legally sold in the US. Their concerns are spelled out in their petition.
They voiced the opinion that the 23 mg dose was developed to maintain a unique market position: "It appears that in order to keep one form of donepezil available under patent protection, Eisai developed the higher 23 mg dose." The 23 mg dose does do that; there is no practical way in which generic 5 mg and 10 mg tablets can be combined to achieve a 23 mg dose. If 23 mg is a useful dose, than it must be purchased as Aricept, not as a generic product.
Mostly, though, Public Citizen attacked the impact of the 23 mg dose, stating it does not offer much benefit over the 10 mg dose (which is available as a generic product), but does produce significantly more adverse effects.
Is 23 mg More Effective?
Data presented to the FDA showed 23 mg produced a significant improvement in the Severe Impairment Battery (SIB) scores. The SIB is a test that has a range of possible scores from zero to 100. Memory counts for up to 14 points. Other categories include language (up to 46 points), attention, and praxis (control of movements). The 23 mg dose produced about a two point improvement out of a possible 100 point scale over the 10 mg dose.
The other primary endpoint studied was the CIBIC-Plus, which measures how the person is actually functioning. There was no statistical difference between outcomes at either dose.
There were two secondary endpoints. There was no statistical difference between outcomes at the two doses. One of these secondary endpoints was the MMSE.
Does 23 mg Produce More Adverse Effects?
About four times as many people taking 23 mg had nausea. Urinary incontinence was almost double. Confusion, weight loss, fatigue, diarrhea, and vomiting also were more common with the 23 mg dose.
Donepezil Has a Long Half-life
The half-life of donepezil is about three days (it takes that long for the body to clear half of an ingested dose). That means it takes about two weeks to completely clear a dose. If an adverse effect happens, it will be a fairly long time until the drug is gone from the body.
The Aricept 23 mg dose approval by the FDA has generated significant discussion in the healthcare field, if nothing else. A Google search for the product and FDA generated 1.5 million hits (20 July 2011).
Sources
Undated Aricept marketing document distributed in 2011
Public Citizen Petition to Ban 23 Milligram dose of Donepezil (Aricept). May 18,2011. (Accessed July 23, 2011)
James Cooper - I'm on the faculty of a health science department at a large university. Most of my articles derive from conferences or presentations ...
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