What are side effects? - Health questions - NHS Choices
Side effects are unwanted symptoms caused by medical treatment. They're also called adverse effects or adverse reactions.
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You should report side effects from a medicine through the Yellow Card Scheme. For more information, go to How do I report side effects from a medicine?
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If you think that you or someone you are with may be having a serious allergic reaction to a medicine, phone 999 and ask for immediate medical help. Contact your GP or pharmacist immediay if:
Side effects can range from mild, such as drowsiness or feeling sick (nausea), to severe, such as life-threatening conditions. The risk of getting side effects varies from person to person.
The PIL supplied with your medicine will list its known side effects. If you no longer have your medicine’s PIL, you can find a copy on the electronic Medicines Compendium (eMC).
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Next review due: 24/03/2016.
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You don’t need to see your GP with mild side effects, such as nausea, if you feel you can manage these on your own.
The PIL will show whether each side effect is:
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Side effects are unwanted symptoms caused by medical treatment. They’re also called "adverse effects" or "adverse reactions". All medicines can cause side effects, particularly if they’re not used as prescribed.
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Page last reviewed: 24/03/2014.