Posted by: Thixia | May 3, 2008

Selective serotonin reuptake inhibitors (SSRIs)

Selective serotonin reuptake inhibitors (SSRIs)


Selective serotonin reuptake inhibitors (SSRIs) are a newer class of antidepressant medications. The first drug in this class was fluoxetine (Prozac), which hit the market in 1987.


How SSRIs work


It’s not clear precisely how SSRIs affect depression. Certain brain chemicals called neurotransmitters are associated with depression, including the neurotransmitter serotonin (ser-oh-TOE-nin). Some research suggests that abnormalities in neurotransmitter activity affect mood and behaviour.  SSRIs seem to relieve symptoms of depression by blocking the reabsorption (reuptake) of serotonin by certain nerve cells in the brain. This leaves more serotonin available in the brain. As a result, this enhances neurotransmission — the sending of nerve impulses — and improves mood. SSRIs are called selective because they seem to affect only serotonin, not other neurotransmitters.


SSRIs approved to treat depression


Some SSRIs are available in extended-release form or controlled-release form, often designated with the letters XR or CR. These forms are intended to provide controlled release of the medication throughout the day or for a week at a time with a single dose.

Here are the SSRIs that have been approved by the Food and Drug Administration specifically to treat depression, with their generic or chemical names followed by available brand names in parentheses:


·    Citalopram     (Celexa)

·    Escitalopram (Lexapro)

·    Fluoxetine      (Prozac, Prozac Weekly)

·    Paroxetine     (Paxil, Paxil CR)

·    Sertraline       (Zoloft)


Some of these medications may also be used to treat conditions other than depression.


Side effects of SSRIs


SSRIs are generally considered safer than other classes of antidepressants. They’re less likely to have adverse interactions with other medications, and they’re less dangerous if taken as an overdose. All SSRIs have the same general mechanism of action and side effects. However, individual SSRIs have some different pharmacological characteristics. That means you may respond differently to certain SSRIs or experience different side effects with different SSRIs. For instance, you may have unpleasant side effects with one SSRI but not another.


Side effects of SSRIs include:


·    Nausea

·    Sexual dysfunction, including reduced desire or orgasm difficulties

·    Headache

·    Diarrhea

·    Nervousness

·    Rash

·    Agitation

·    Restlessness

·    Increased sweating

·    Weight gain

·    Drowsiness

·    Insomnia


You may experience less nausea with controlled-release forms of SSRIs.


Serotonin syndrome and SSRIs


A rare but potentially life-threatening side effect of SSRIs is serotonin syndrome. This condition, characterized by dangerously high levels of serotonin in the brain, can occur when an SSRI interacts with antidepressants called monoamine oxidase inhibitors (MAOIs). Because of this, don’t take any SSRIs while you’re taking any MAOIs or within two weeks of each other. Serotonin syndrome can also occur when SSRIs are taken with other medications or supplements that affect serotonin levels, such as St. John’s wort. Serotonin syndrome requires immediate medical treatment.


Signs and symptoms of serotonin syndrome include:


·    Confusion

·    Restlessness

·    Hallucinations

·    Extreme agitation

·    Fluctuations in blood pressure

·    Increased heart rate

·    Nausea and vomiting

·    Fever

·    Seizures

·    Coma


Safety concerns with SSRIs


Studies show that Paxil increases the risk of birth defects in women taking the drug during their first trimester of pregnancy. Women who take Paxil during their first three months of pregnancy are nearly two times more likely to give birth to a child with a birth defect — in particular a heart defect — than are women taking other antidepressants.


The American College of Obstetricians and Gynecologists recommends avoiding Paxil during pregnancy, if possible. If you’re taking Paxil and you’re considering getting pregnant, talk to your doctor or mental health professional about switching to another antidepressant or discontinuing treatment. Don’t stop taking Paxil without contacting your doctor first, though.


In addition, in July 2006, the FDA issued a warning that infants whose mothers took SSRIs while pregnant may be at an increased risk of persistent pulmonary hypertension. In particular, this risk is increased in women who take SSRIs at 20 weeks or later in their pregnancy. This rare but serious lung problem occurs when a newborn’s circulatory system doesn’t adapt to breathing outside the womb.


Stopping treatment with SSRIs


SSRIs aren’t considered addictive. However, stopping treatment abruptly or missing several doses can cause withdrawal-like symptoms, including:


·    Nausea

·    Headache

·    Dizziness

·    Lethargy

·    Flu-like symptoms


This is sometimes called discontinuation syndrome. Talk to your doctor before stopping so that you can gradually taper off.


Suicidal feelings and SSRIs


In some cases, antidepressants may be associated with worsening symptoms of depression or suicidal thoughts or behavior. These symptoms or thoughts are most likely to occur early in treatment or when you change your dosage, but they can occur at any time during treatment. Be sure to talk to your doctor about any changes in your symptoms. You may need more careful monitoring at the beginning of treatment or upon a change in treatment, or you may need to stop the medication if your symptoms worsen.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s


%d bloggers like this: