Selective serotonin reuptake inhibitor

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**Selective serotonin reuptake inhibitors** are a group of medications. They are usually called **SSRIs**. They are used to treat depression, anxiety disorders, and some other problems.

In many countries, SSRIs are prescribed more often than any other type of antidepressant.

Examples of common SSRIs are fluoxetine (Prozac), paroxetine (Paxil), citalopram (Celena), and escitalopram (Lexapro).

## Medical uses
SSRIs are mainly used to treat:

### Anxiety disorders
SSRIs work well for generalized anxiety disorder. They help decrease people's anxiety. This can help them participate in counseling to learn how to deal with their anxiety.

SSRIs also work well for obsessive-compulsive disorder (OCD). They are the first-choice treatment for people with very bad OCD. Like with depression and generalized anxiety disorder, SSRIs are not a cure; people need to participate in counseling and other treatments too. However, people with OCD who took an SSRI are about twice as likely to do well in treatment than people not taking an SSRI.

Fluoxetine (Prozac) and paroxetine (Paxil) are the only medications the United States Food and Drug Administration has approved for treating post-traumatic stress disorder (PTSD). Medications alone usually will not cure PTSD; they need to be combined with counseling. Except for Prozac and Paxil, most other SSRIs do not seem to help PTSD.

### Eating disorders
When a person starts to get treatment for bulimia nervosa or binge eating disorder, SSRIs can be a helpful first step. Over short periods of time, they can decrease some of the symptoms of these eating disorders. For example, for a short while, people taking SSRIs do less binge eating. However, SSRIs only seem to help for a short period of time. However, if a person with anorexia also has depression, anxiety, or OCD, SSRIs could help treat those problems.

Another group of antidepressants, called tricyclic antidepressants, treat chronic pain better than SSRIs do. However, tricyclic antidepressants have many more side effects than SSRIs do. Because of this, some doctors prescribe paroxetine or citalopram for chronic pain, because the side effects are not as bad.

SSRIs increase the amount of serotonin that the brain can use. This is true for young adults up to age 24.  

In 2004, the United States Food and Drug Administration (FDA) looked at clinical trials on children with major depressive disorder. They found that children taking SSRIs had:
* An 80% higher risk of "possible suicidal ideation and suicidal behavior".
* About a 130% greater risk of agitation (getting angry and upset easily) and hostility (acting angry towards other people).

In both the United States and the United Kingdom, only three SSRIs are approved to treat children:
* Fluoxetine (Prozac), to treat children with depression. These problems include erectile dysfunction, not being able to have an orgasm, not wanting to have sex, and not enjoying sex. 

Sexual problems are one of the most common reasons why people stop taking SSRIs.

### Bleeding
When a person takes SSRIs along with anticoagulant (blood-thinning) medications, they are a little more likely to have bleeding problems. For example, the person is more likely to have bleeding in their digestive system (gastrointestinal tract), or to bleed after they have surgery.
* Are on blood-thinning medications, like warfarin (Coumadin); AND
* Are on medications that stop blood cells called platelets from forming blood clots, like aspirin; AND
* Are taking a type of painkiller called nonsteroidal anti-inflammatory drugs (NSAIDS), like ibuprofen; AND
* Have problems with their liver, like liver disease or liver failure.

### Other problems
Most SSRIs can also make a person:
* More likely to break a bone.
* Feel very restless and unable to stand still (akathisia).
* Be very  to bright lights.

## Stopping suddenly
If a person stops taking SSRIs suddenly, they can get side effects that are painful or distressing. The medical name of these side effects is serotonin discontinuation syndrome. This can cause:
* Nausea
* Headache
* Dizziness
* Pain in the whole body
* Strange feelings on the skin
* Trouble sleeping
* Feeling like the body is being shocked with electricity

A person and their doctor should come up with a plan for how to stop taking an SSRI. If possible, the person should slowly decrease the amount of medication they are taking, bit by bit, over a few weeks.

SSRI overdoses can cause:
* Serotonin syndrome
* Coma
* Seizures
* Poisoning of the heart

## Drug interactions
It is not safe to take some drugs with SSRIs. Taking these drugs with SSRIs can cause serotonin syndrome. Here are some examples of drugs that cannot be taken with SSRIs:

* Some other medicines for depression and anxiety:
** Monoamine oxidase inhibitors (MAOIs)
** Tricyclic antidepressants
** Serotonin-norepinephrine reuptake inhibitors (SNRIs)
** Lithium
** Buspirone (Buspar)
** Mirtazapine (Remeron)
* Some pain medications:
** Pethidine/meperidine (Demerol)
** Tramadol (Ultram)
* Other medications:
** Dextromethorphan, an over-the-counter cough medicine
** St. John's Wort, an herb that some people use to treat depression
** MDMA (Ecstasy), an illegal drug

## Related pages
* Serotonin
* Depression
* Anxiety disorders

## References