DonepezilDonepezil Hydrochloride

About Donepezil

Donepezil is a reversible inhibitor of acetylcholinesterase, the enzyme that breaks down acetylcholine, so it raises the level of this chemical messenger, whose shortage is thought to underlie some of the memory and thinking symptoms of Alzheimer’s disease; there is no evidence that it alters the course of the disease. The label covers dementia of the Alzheimer’s type at every stage, and safety and effectiveness in children have not been established. Treatment starts at 5 mg once a day in the evening, just before bed, and the dose is not raised to 10 mg until after 4 to 6 weeks; 10 mg is the top dose for mild to moderate disease. In moderate to severe disease the dose can go up to 23 mg, but only after at least 3 months on 10 mg.

There is no boxed warning, and the only contraindication is an allergy to donepezil or to piperidine derivatives. Like other cholinesterase inhibitors it can slow the heart rate or cause heart block, fainting has been reported, and QTc prolongation and torsade de pointes have been reported since approval. It can cause stomach ulcers and bleeding, so people with a history of ulcers or who take NSAIDs are watched, and nausea, vomiting and weight loss are more common at 23 mg than at 10 mg. It may also cause bladder outflow obstruction or seizures, it is prescribed with care to people with asthma or obstructive lung disease, and it exaggerates succinylcholine-type muscle relaxation during anesthesia. Nausea, diarrhea, insomnia, vomiting, muscle cramps, fatigue and loss of appetite are the most common side effects.

The 23 mg tablet is swallowed whole and never split, crushed or chewed, and the orally disintegrating tablet melts on the tongue and is followed by water. If doses have been missed for 7 days or more, the prescriber is asked before restarting, and dentists and surgeons should know about it before any procedure. Several versions have left the market: Aricept ODT and Aricept oral solution are discontinued, and so is Adlarity, a once-weekly skin patch in 5 mg and 10 mg per day strengths approved in 2022, while generic orally disintegrating tablets remain.

Taking Donepezil

How to take it

Once a day in the evening, just before bed, with or without food. Swallow the 23 mg tablet whole, without splitting, crushing or chewing it; let an orally disintegrating tablet melt on the tongue, then drink some water.

If you miss a dose

If a dose is missed, skip it and take the next dose at the usual time; do not take two doses at once. If it has been missed for 7 days or more, talk with the prescriber before starting again.

Storage

At room temperature, 59 to 86°F (15 to 30°C), out of reach of children.

Interactions to know about

It can interfere with anticholinergic medicines, and it exaggerates the effect of succinylcholine-type muscle relaxants used in anesthesia, so tell any surgeon or dentist. NSAIDs add to the risk of stomach bleeding. Ketoconazole and quinidine can slow its breakdown, while phenytoin, carbamazepine, dexamethasone, rifampin and phenobarbital can speed it up.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Donepezil differs from pharmacy to pharmacy

Generic 5 and 10 mg tablets have many makers, which makes them the form most likely to be on a pharmacy’s flat-price generic list, and for them the dispensing fee can be much of the quote. The 23 mg tablet has fewer makers and the orally disintegrating tablets fewer still, so not every pharmacy stocks them, and one that rarely fills them may order them in and price them as slow-moving items.

A prescription that names Aricept and does not allow substitution is priced as a brand. Each strength is priced as its own product, so the step from 10 mg to 23 mg is a new fill.

Ways to pay less for Donepezil without insurance

• Ask for generic donepezil, and make sure the prescription allows substitution rather than naming Aricept only.
• Ask for a ninety-day supply once the dose has been stable.
• If swallowing tablets is not a problem, ask the prescriber whether regular tablets would suit you, since the orally disintegrating form has fewer makers.
• For the 23 mg tablet, compare more than one pharmacy, since fewer makers supply it.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Donepezil

1. 1.Should I take my dose at bedtime, and does it matter whether I take it with food?
2. 2.What should I do if I have missed several days of doses?
3. 3.Do any of my medicines, such as anti-inflammatories, bladder medicines or heart medicines, interact with it?
4. 4.Should I tell my dentist or surgeon that I take it before a procedure?

Related medications