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Selective Serotonin Reuptake Inhibitors (SSRIs)

Selective serotonin reuptake inhibitors (SSRIs) belong to a class of medication called “antidepressants.”

Citalopram (Celexa®) Escitalopram (Cipralex®) Fluoxetine (Prozac®) Fluvoxamine (Luvox®) Paroxetine (Paxil®, Paxil CR®) Sertraline (Zoloft®)

What is this medication used for?

Selective serotonin reuptake inhibitors (SSRIs) are not approved by Health Canada for use in children and adolescents.

However, SSRIs may help treat depression, generalized anxiety disorder, social anxiety disorder, panic disorder, obsessive compulsive disorder (OCD), post-traumatic stress disorder (PTSD), eating disorders such as anorexia nervosa and bulimia nervosa, selective mutism, separation anxiety and significant premenstrual mood changes.

When potential benefits outweigh risks, SSRIs may be prescribed “off-label.” Learn more about off-label medication use:

Tell your doctor or pharmacist if you:

  • Have allergies or bad reactions to a medication
  • Take (or plan to take) other prescription or non- prescription medications, including natural medicines. Some medications interact with SSRIs. Your doctor may adjust medication doses or monitor for side effects
  • Have a history (or family history) of heart, kidney or liver disease, seizures, arrhythmias, diabetes, glaucoma or bipolar disorder
  • Miss a menstrual period, are pregnant, breast-feeding or planning a pregnancy
  • Use alcohol or street drugs. Taking SSRIs together with certain substances may cause a bad reaction. Learn more at

When will the medication start to work?

You (or your family members) may notice improvements in sleep, appetite and energy within the first 2 weeks. However, it may take up to 4 weeks before you begin to feel better. Full beneficial effects may take 6 to 8 weeks or longer.

SSRIs take time to work. Continue taking this medication as prescribed, even if you are feeling better or there are no improvements in the first few weeks. Talk with your doctor before you increase, decrease or stop taking this medication, even if you feel that this medication has not been helpful or if side effects are too bothersome. Your doctor may recommend switching you to a different medication.

This medication is not addictive. Do not stop taking it before talking to your doctor.

Possible common or serious side effects:

Side effects may be more common when starting a medication or after a dose increase. Talk to your doctor, nurse or pharmacist if any side effect concerns you.

  • Dizziness, drowsiness or headache
  • Nervousness, agitation or anxious thoughts
  • Insomnia or abnormal dreams
  • Fatigue or lack of energy
  • Nausea, diarrhea or constipation
  • Decreased appetite or dry mouth
  • Increased sweating
  • In adolescents/adults: changes in sexual performance or interest

Contact your doctor immediately if you experience:

  • Thoughts of hurting yourself, hostility or suicide
  • Changes in mood to an unusual state of excitement, irritability or happiness
  • Uncomfortable awareness of your own heartbeat, or sudden and brief loss of consciousness
  • Muscle twitches or stiffness
  • Uncomfortable sense of inner restlessness or agitation
  • Unexpected rash, seizure, fever or excessive sweating
  • Unusual bruising or bleeding

How does this medication work?

Most SSRIs are taken once daily at the same time each day, with or without food. However, fluvoxamine may be taken twice daily at high doses. Usually, you will start with a low dose and slowly increase this dose over several days to weeks, based on how you tolerate it.

Most SSRIs are available as tablets or capsules. Special formulations include fluoxetine liquid solution, orally disintegrating escitalopram tablets that quickly disintegrate when placed on the tongue and can be swallowed without water, and controlled- release (CR) paroxetine tablets which should be swallowed whole and should not be chewed, crushed or mixed with water.

What precautions should my doctor and I be aware of when taking this medication?

  • While taking SSRIs, if you feel dizzy, drowsy or slowed down, do not drive a car or operate heavy machinery. Alcohol could make this worse. Try to avoid alcohol while taking SSRIs.

  • SSRIs and medications like it are associated with a rare side effect called “serotonin syndrome,” especially when used in combination with other serotonergic drugs such as MAO inhibitors and most other antidepressants. Symptoms include diarrhea, sweating, increased heart rate, tremors, severe muscle stiffness and increased agitation.

  • Do not to stop taking most SSRIs suddenly. Excluding fluoxetine, stopping an SSRI abruptly is associated with “antidepressant discontinuation syndrome.” This involves flu-like symptoms, trouble sleeping, nausea, irritability, headache and abnormal sensations that feel like electric shocks, burning, tingling or numbness. If stopping or changing medications, your SSRI dose should usually be reduced slowly over several weeks.

What special instructions should I follow while using this medication?

  • Keep all appointments with your doctor and the lab.

  • Your doctor may want to talk to you within 1-2 weeks of starting an SSRI, and meet with you over time to make sure it is working well for you and check for side effects.

  • Do not allow anyone else to use your medication.

What should I do if I forget to take a dose of this medication?

If you forget to take a dose of an SSRI, take the missed dose as soon as you remember. However, if it is within 4 hours of your next schedule dose, skip the missed dose and continue with your regular schedule. DO NOT double your next dose to try to ‘catch up’.

How do I store this medication?

Keep SSRIs in the original container, stored at room temperature away from moisture and heat and protected from light. Keep SSRIs out of reach and sight of children.

While there are some differences between individual SSRIs, all of them act in a similar way. SSRIs increase levels of the brain chemical serotonin. This brain chemical does not function properly in people who have depression, anxiety or OCD. The exact way that SSRIs improve symptoms of depression, anxiety disorders and other conditions is not known.

How well does the medication work in children and adolescents?

Escitalopram, fluoxetine, sertraline and citalopram are the most well-studied SSRIs for treatment of children and adolescents with depression and anxiety disorders. Certain SSRIs have shown to be better than placebo (an inactive pill) for treatment of depression, generalized and social anxiety disorders, panic disorder, OCD, selective mutism and separation anxiety in children and adolescents. Paroxetine is not usually used as it has shown to be ineffective for treatment of depression and is associated with more side effects than other SSRIs in children and adolescents.

SSRIs are sometimes prescribed for children and adolescents with other conditions such as PTSD, anorexia nervosa and bulimia nervosa when other treatments have not been effective. Whenever possible, the addition of talk therapy, such as Interpersonal Therapy (IPT) for depression or Cognitive Behavioural Therapy (CBT), may help increase the potential for benefit.

How long should I take the medication for?

This depends on the symptoms you have, how frequently they occur and how long you have had them. Most people need to take SSRIs for at least 6 months. This allows time for symptoms to stabilize and function to improve. After this time, you and your doctor can discuss the benefits and risks of continuing treatment.

If you have had severe anxiety, OCD symptoms, or several severe episodes of depression and you tolerate the SSRI well, you may be asked to take the SSRI on an ongoing basis. Continuing treatment will significantly decrease the chance that your anxiety or OCD symptoms will return or that you will have another episode of depression.

Do not increase, decrease or stop taking SSRIs without discussing it with your doctor, even if you are feeling better. If you stop taking SSRIs suddenly, it is possible that your symptoms may return or you may have a bad reaction.

TIP: Use the Kelty Mental Health Antidepressant Monitoring Form for Children and Adolescents to help measure your progress on this medication.

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