Restarting Donepezil After Stopping

Answer

Thanks so much for reaching out to us!

There is no set-in-stone recommendation for what dose to restart taking Aricept (donepezil) at if you have been off it for 7 days. However, as I discuss in the next sections, donepezil has a very long-half life, and stays in your system for at least a couple of weeks after your last dose.

After being off the drug for 7 days, it's likely you can restart at the 10mg dose without a significant increase in the risk of side effects occurring, but everyone's medical situation is different, which is why you always want to loop in your doctor about what is going on. They can help provide specific guidance. 

If you do restart Aricept at the 10mg dose and you are finding the side effects to be particularly troublesome, decreasing the dose to 5mg and slowly titrating up will likely make the side effects more tolerable.

Donepezil Lasts A Long-Time In Your System

As mentioned, donepezil has a long half-life, which is the amount of time it takes for 50% of a drug to be metabolized. In general, it takes around 5 half-lives for a drug to be considered completely eliminated from your system.

Donepezil has a reported half-life of 70-100 hours. If we use 70 hours as a measuring stick, it would take around 14 days for the drug to be completely metabolized.

So, even though your husband has been off the drug for 7 days, it is still in his system, making restarting at a 10mg dose (his previous dose) a definite possibility.

Why Is Donepezil Started At A Low Dose?

Donepezil, while being generally well-tolerated overall, is associated with several side effects, many of which are dose-dependent (i.e., the higher the dose, the higher the risk of side effects).

These side effects include:

• Nausea
• Diarrhea
• Insomnia
• Muscle cramps
• Fatigue
• Weight loss

The prescribing information for donepezil recommends starting at 5mg and increasing to 10mg only after 4 to 6 weeks of consistent use. This is based on data showing that the rate and severity of side effects is greatly decreased if the dose is increased only after this titration. I have included a chart below that illustrates this.

Restarting Donepezil

So, selecting the appropriate dose to restart donepezil at really depends on how long you have been off of the drug.

Based on the half-life of the drug and the fact it lasts so long in your system, most people who were previously taking 10mg and have only missed a few doses, or have been off for a week or two, can probably restart the drug at 10mg without much of an increase in the risk of side effects.

If it has been longer than a few weeks, it likely should be restarted at 5mg and titrated over a 4 to 6-week period to avoid the increased risk of side effects.

I want to emphasize that this recommendation is just a generalization based on what is known about the drug, and you really should talk to your doctor about what is most appropriate for your medical situation.

Being extra cautious and starting at a low dose may be what is recommended for some people, while others may be relatively safe just starting back at 10mg.

I also want to mention that although you didn't mention the 23mg dose of donepezil, it is a strength that is available and follows the same recommendation that lower doses should be used first before the higher dose is given.

Final Words

Thanks for reaching out and I hope you found this helpful.