Medication Overview

Aricept is the brand name for Donepezil, a medication primarily prescribed to treat mild, moderate, and severe Alzheimer’s disease symptoms. It belongs to the class of drugs known as acetylcholinesterase inhibitors.

Mechanism of Action

Donepezil works by inhibiting the enzyme acetylcholinesterase, thereby increasing the levels of acetylcholine in the brain. Elevated acetylcholine levels enhance cholinergic neurotransmission, which may improve cognitive function in Alzheimer’s disease patients.

Indications

Aricept is indicated for the management of symptomatic treatment of Alzheimer’s disease. It is effective for mild, moderate, and severe stages of Alzheimer’s. There are no indications for the use of Aricept in other types of dementia or for other conditions.

Dosage Forms

Aricept comes in different dosage forms, including film-coated tablets and orally disintegrating tablets. The film-coated tablets are available in 5 mg, 10 mg, and 23 mg doses. The orally disintegrating tablets come in 5 mg and 10 mg doses.

Recommended Dosages

Initial dosage is usually 5 mg once daily in the evening, just before bedtime. For patients who have been on 5 mg for at least four to six weeks, the dose may be increased to 10 mg. For those who have tolerated 10 mg for at least three months, the dose can be increased to 23 mg once daily.

Administration Guidelines

Aricept should be taken in the evening prior to bedtime, with or without food. The tablets should be swallowed whole with water. The orally disintegrating tablets should dissolve on the tongue without the need for water.

Missed Dosages

If a dose is missed, take it as soon as remembered unless it is almost time for the next dose. Do not take two doses at the same time to make up for the missed dose. Continue with the regular dosing schedule.

Pharmacokinetics

After oral administration, Donepezil is well absorbed, reaching peak plasma concentrations within 3 to 4 hours. The half-life of Donepezil is approximately 70 hours, allowing for once-daily dosing. It is metabolized in the liver via cytochrome P450 and excreted in urine.

Bioavailability Details

The bioavailability of Donepezil is nearly 100%, ensuring efficient absorption into the system when administered orally. Food does not significantly affect its absorption.

Adverse Reactions

Common side effects include nausea, diarrhea, insomnia, muscle cramps, fatigue, and anorexia. Rare but severe side effects include bradycardia, gastrointestinal bleeding, seizures, and severe skin reactions.

Monitoring Parameters

Patients should be monitored for heart rate, as bradycardia can occur. Gastrointestinal symptoms should also be monitored due to the risk of ulceration and bleeding, particularly in at-risk populations like those with a history of ulcers.

Drug Interactions

Donepezil can interact with anticholinergic medications, reducing its effectiveness. There may also be interactions with drugs metabolized by the CYP2D6 and CYP3A4 enzymes, such as ketoconazole, quinidine, and certain antidepressants.

Contraindications

Aricept is contraindicated in patients with hypersensitivity to Donepezil or piperidine derivatives. It should be used with caution in patients with a history of asthma or obstructive pulmonary disease.

Special Populations

In elderly patients, the same dosing regimen is applicable. Specific dose adjustments are not required based on age. However, individual responses should be closely monitored to optimize dose titration.

Renal Impairment

No dose adjustment is required for patients with renal impairment, as renal elimination is not a major pathway for Donepezil.

Hepatic Impairment

Patients with mild to moderate hepatic impairment do not require dosage adjustment. However, increased monitoring may be warranted due to the hepatic metabolism of Donepezil.

Pregnancy and Lactation

There is insufficient data on the use of Donepezil during pregnancy and lactation. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Caution is advised if Aricept is administered to breastfeeding women.

Storage Conditions

Store Aricept at room temperature between 15°C and 30°C (59°F and 86°F). Protect from moisture and light. Keep the medication out of reach of children.

Disposal Instructions

Unused or expired medication should be disposed of in accordance with local regulations and guidelines. Do not flush medications down the toilet or pour them into a drain unless instructed to do so.