As well as potential benefits, every psychiatric drug has the potential to cause unwanted side effects. These can occur after both short-term and long-term use.
Mild side effects might:
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stop once your body has got used to the drug
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be manageable by adjusting how you take the drug (such as taking it with food, or at a different time of day).
Severe side effects might:
- mean that you need to stop taking the drug and seek medical help.
What kind of side effects might I get?
This depends on the drug and your individual reaction to it. Some people get side effects and some people don't. If you do get side effects, these could be mild or severe – there is no way to know how you will react before you start taking the medication.
If you get side effects, it's generally up to you to decide whether the benefits of taking the drug outweigh the side effects or not.
You can read about side effects associated with particular types of medication on our pages about:
Alternatively, if you want to know about a specific drug, you can look it up in our medication A–Z.
What should I do if I get side effects?
| If you feel: |
Then you should: |
| seriously unwell |
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Get medical advice immediately – see your GP, local pharmacist, or go to A&E.
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Do not drive or operate machinery.
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| moderately unwell or very worried |
- Get medical advice within 12 hours – see your GP, local pharmacist, or nurse prescriber.
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| mildly unwell or uncomfortable |
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Get medical advice in the next few days – see your GP, local pharmacist, or nurse prescriber, or talk to your care coordinator if you have one.
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If you have only just started taking the medication, you could consider waiting a few days to see if the side effect wears off by itself.
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You can also report any side effect you experience to the Medicines and Healthcare Products Regulatory Agency (MHRA) using the Yellow Card scheme.
How likely is it that I'll get side effects?
The likelihood of experiencing different side effects varies for each drug. Your risk of experiencing a side effect is described in most Patient Information Leaflets (PILs – the leaflet that comes in the drug packet) like this:
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affects more than 1 person in 10
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affects 1 to 10 people in 100
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affects 1 to 10 people in 1,000
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affects 1 to 10 people in 10,000
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affects fewer than 1 person in 10,000
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We do not know how many people are affected
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In other words, if the risk is described as rare (fewer than 1 in 10,000), that means 9,999 people out of 10,000 probably won't experience that side effect.
This data is available for all newer drugs, but not for some of the oldest drugs.
This information was published in 2016. We will revise it in 2019.
