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Coming off psychiatric medication
Explains why you might decide to come off psychiatric medication, how to do this safely and where you can go for support. Also includes tips for friends and family wanting to support someone who is coming off medication.
What is a drug's half-life?
The half-life of a drug is the time it takes for the amount of active substance in your body to reduce by half.
It's important to know the half-life of any medication you take because:
- A short half-life usually means more withdrawal problems
- A long half-life usually means fewer withdrawal problems
If you're taking a drug with a short half-life and having problems with withdrawal, you might be able to switch to a similar drug with a longer half-life. The longer half-life drug might be easier to come off.
Example: half-life when coming off a drug
For 3 months, you've taken a prescribed drug called X:
- Drug X contains 600mg of active ingredient
- Drug X has a half-life of 48 hours (2 days)
When you stop taking it, the active ingredient will take 48 hours to reduce to 300mg in your body.
It will take another 48 hours for the 300mg to go down to 150mg. Then another 48 hours to reach 75mg, and so on.
Half-life can also guide you on roughly how long it takes for a drug to reach a stable level in your body. This information can be useful when you first start taking it. Generally, it takes about 5 times the half-life to build a stable level.
How can I find out the half-life of my medication?
The Patient Information Leaflet (PIL) should clearly set out the drug's half-life. This leaflet should come in the package with your medication.
But you can also compare half-lives by looking at our comparison tables. In our tables, the half-life is not an exact figure – it can vary based on different factors.
On these pages, you should only use the tables as a guide to roughly compare types of:
Example: building to a stable level
You've just started taking drug Y:
- Drug Y contains 100mg of active ingredient
- Drug Y has a half-life of 12 hours (0.5 days)
If it takes roughly 5 times the half-life to reach a stable level:
- 12 hours x 5 = 60 hours (2.5 days)
It should take around 2 and a half days for your body to reach a stable level of the active ingredient.
This information was published in March 2021.
This page is currently under review. All content was accurate when published.
References and bibliography available on request.
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