About Aricept(Donepezil)
Aricept, which is claimed to be the #1 prescription drugagainst Alzheimer's disease in the USA these days, belongs to the class ofchemical substances, called cholinesterase inhibitors. It could be thrilling tonote, that during World War II the representatives of this very group ofchemicals were mainly developed for warfare purposes: such terrifying anddeadly weapons as neuroparalytic gases sarin, soman, and VX also belong to theclass of cholinesterase inhibitors.
Happily, nowadays the properties of cholinesteraseinhibitors are used mainly for peaceful purposes; one of them is to help peopleconquer Alzheimer'sdisease - one of the most devastating mental illnesses of elderly people.
Today there are three substances of cholinesterase inhibitorsgroup, which are approved for medicinal use � donepezil, galantamine and rivastigmine.However, it is only donepezil or Aricept as the brand medication, which isapproved for the use in patients on all stages of Alzheimer's disease (othersare used only for mild to moderate conditions). Donepezil is said to be themost potent among other representatives of cholinesterase inhibitors.
Aricept was developed by Eisai Inc. and approved by the FDAin 1996. It is currently co-promoted by Eisai Inc. and Pfizer Inc.
There is a preliminary research data claiming that combinationAricept and memantine,another anti-Alzheimer's medication, may significantly increase theeffectiveness of the treatment.
Aricept as Alzheimer'sTreatment
As was mentionedearlier, Aricept is part of a group of drugs called acetycholinesteraseinhibitors used to treat mild to moderate cognitive symptoms ofAlzheimer's. There is no clinical evidence that it can actually alter thecourse of the disease or help repair damaged brain cells.
It is believed that the chemical acetylcholine, whichtransmits messages between brain cells in the area responsible for memory andacquiring new information, is reduced in the brains of people with Alzheimer'sdisease.
Acetycholinesterase inhibitors, such as Aricept, helpprevent the breakdown of this important chemical, therefore helping to delaydeterioration. In some cases it has delayed symptoms by around 12 months.
In one study where some people received Aricept and othersreceived a placebo, those who took the drug were twice as likely to show someimprovement in thinking and understanding. For many it delayed their declinefor up to 12 months.
For some people the drug doesn't have any effect at all or,if it does, their condition stays the same when it could have been expected todeteriorate.
And it doesn't have any effect in the later stages ofAlzheimer's because there are so few acetylcholine-producing cells left.
The drug is only available in prescription form and it's upto a doctor to decide whether it's suitable for the individual Alzheimer'ssufferer.
Dosage
Aricept is available in tablet form or an orallydisintegrating tablet form, and is commonly started at 5 mg a day. If it's welltolerated after 4 to 6 weeks, the dosage may be increased to 10 mg a day.
Aricept has beenapproved by the FDA in dosages of 5 to 10 milligrams for patients with mild tomoderate cases of Alzheimer's and in a dose of 10 to 23 milligrams for moresevere cases. There are ongoing efforts requesting FDA to ban the 23-mg versionof the drug and to warn patients and physicians against taking two 10-mg. pillsper day if the higher dosage is removed from the market.
Clinical trialsof Aricept submitted to the FDA for approval show no significant benefit fromthe 23-mg version compared to the 10-mg version. But the increased adverseeffects from the higher dosage include a slowed pulse rate, nausea, vomiting,diarrhea, urinary incontinence, fatigue, dizziness, agitation, confusion andanorexia. Vomiting, which occurred more than 3 1/2 times more frequently inthose taking the high dosage, is a particularly dangerous side effect forAlzheimer's patients, because it can lead to pneumonia, massivegastrointestinal bleeding, esophageal rupture and even death.
"With noevidence of an added advantage in benefit to patients, the clear increase inrisk should have been more than adequate grounds for denying approval,"said Dr. Sidney Wolfe, director of Public Citizen's Health Research Group."It is inexcusable that FDA approved this higher dose. Its prompt removalwould belatedly fulfill the agency's mission to allow only drugs whose benefitsoutweigh their risks to be marketed."
Side Effects
While applied to the normal doses of the drug, side effectsof the drug are generally well-tolerated. Nausea, vomiting, diarrhea, loss ofappetite/weight loss, dizziness, drowsiness, weakness, trouble sleeping,shakiness (tremor), or muscle cramps may occur as your body adjusts to thedrug. These effects usually last 1-3 weeks and then lessen. If any of theseeffects persist or worsen, notify your doctor or pharmacist promptly. Rememberthat your doctor has prescribed this medication because he or she has judgedthat the benefit to you is greater than the risk of side effects.
Many people using this medication do not have serious sideeffects. Tell your doctor right away if any of these serious side effectsoccur: slow/irregular heartbeat, fainting, trouble urinating, severe stomach/abdominalpain, black stools, vomit that looks like coffee grounds, seizures. A very seriousallergic reaction to this drug is rare. However, get medical help right away ifyou notice any symptoms of a serious allergic reaction, including: rash, itching/swelling(especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If younotice other effects not listed above, contact your doctor or pharmacist.
Potential Interactions
Drugs withanti-cholinergic properties that can cross into the brain, such as atropine,benztropine (Cogentin), and trihexyphenidyl (Artane) counteract the effects ofdonepezil and should be avoided during therapy with donepezil.
Donepezil ismetabolized (eliminated) by enzymes in the liver. The rate of metabolism ofdonepezil may be increased by medications that increase the amounts of theseenzymes, such as carbamazepine (Tegretol), dexamethasone (Decadron),phenobarbital, phenytoin (Dilantin), and rifampin (Rifadin). By increasingelimination, these drugs may reduce the effects of donepezil.
Ketoconazole(Nizoral) has been shown to block the enzymes in the liver that metabolizedonepezil. Therefore, concurrent use of ketoconazole and donepezil may resultin increased concentrations of donepezil in the body and possibly lead todonepezil side effects. Quinidine (Quinidex, Quinaglute) also has been shown toinhibit the enzymes that metabolize donepezil and may cause donepezil sideeffects.
Non-steroidal anti-inflammatory drugs (NSAIDs), such asaspirin or ibuprofen, also should be used with caution while taking Aricept,due to the increased risk of stomach ulcers.
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