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Dosage - Selective serotonin reuptake inhibitors (SSRIs)

When prescribing selective serotonin reuptake inhibitors (SSRIs), your doctor will usually select the lowest possible dose thought necessary to improve your symptoms.

This approach is intended to reduce the risk of side effects. If the prescribed dose proves ineffective, it can be gradually increased.

SSRIs are usually taken in tablet form. Depending on the type of SSRI prescribed and the severity of your depression, you'll usually have to take 1 to 3 tablets, once a day.

It will usually take 2 to 4 weeks before you begin to notice the effects of SSRIs. You'll have regular meetings with your doctor when you first start taking SSRIs and you should let them know if you haven't noticed any improvement after 4 to 6 weeks. They may recommend increasing your dose or trying an alternative antidepressant.

It's usually recommended that a course of SSRIs continues for at least 6 months after you feel better, to prevent your condition coming back when you stop. However, if you've experienced previous episodes of depression, a 2-year course may be recommended. Some people with recurring problems are advised to carry on taking medicine indefinitely.

Missed or extra doses

It's important not to miss any of your doses, because this could make your treatment less effective.

If you do miss a dose, take it as soon as you remember, unless it's almost time to take your next dose, in which case you should just skip the missed dose. Don't take a double dose to make up for the one you missed.

If you take more tablets than prescribed, contact your GP as soon as possible for advice. If this isn't possible, contact your local out of hours service, or call NHS 111.

Taking a double dose is unlikely to be harmful, but you should only do so if advised by a medical professional.

Stopping SSRIs

You shouldn't suddenly stop taking SSRIs, even if you feel better. Stopping suddenly can lead to withdrawal symptoms such as:

If your GP or mental health specialist decides to stop your course of SSRIs, they'll reduce the dose gradually over a few weeks.

Page last reviewed: 8 December 2021
Next review due: 8 December 2024