Selective Serotonin Reuptake Inhibitors (SSRI)

Selective Serotonin Reuptake Inhibitors (SSRI)

Selective Serotonin Reuptake Inhibitors (SSRI)

Primer

Selective Serotonin Reuptake Inhibitors (SSRI) are first-line agents for treatment of mood disorders and anxiety disorders. The exact agent chosen will vary depending on prescriber comfort and specific patient factors including gender, diagnosis, symptoms, and patient preference.

Mechanism of Action

SSRIs increase serotonin (5-HT) by inhibiting the serotonin transporter (SERT) and decreasing reuptake into cells. This impacts the serotonin:receptor ratio. Homeostatic forces result in adjustments in serotonin throughout the body.

Side Effects

Common

GI upset, headaches, dry mouth, sexual dysfunction, and weight gain may be common.

Rare

Bleeding risks, antidepressant-induced mania/hypomania, and paradoxical reactions may occur rarely.

Hair Loss

See also: Etminan, M. et al. (2018). Risk of hair loss with different antidepressants: a comparative retrospective cohort study. International clinical psychopharmacology, 33(1), 44-48.

Adverse Events

Withdrawal

See main article: Antidepressant Withdrawal (Discontinuation) Syndrome

Falls, Fractures, and Hyponatremia

Long-term use of SSRIs is associated with an increased risk of falls and fractures that is unrelated to postural hypotension, fractures, and hyponatremia.^[1]

Bleeding

See main article: SSRI and SNRI Bleeding Risks

SSRIs can inhibit platelet aggregation via altering platelet serotonin receptors.
This can increase the risk for gastrointestinal bleeding, and the risk may be doubled with concurrent use of nonsteroidal anti-inflammatory drugs (NSAIDs).
Use of acid-suppressing drugs such as proton pump inhibitors (PPIs) can reduce the risk of gastrointestinal (GI) bleeding.

Suicidal Behaviours

See main article: Introduction to Antidepressants: Suicidal Ideation

There is a risk for increased suicidal behaviour and ideation for youths on antidepressants.

Fetal

See main article: Obstetric and Fetal Pharmacology

SSRI use late in pregnancy has been associated with an increased risk of persistent pulmonary hypertension (PPHN) of the newborn (risk is 3 in 1,000; compared to population risk of 2 in 1,000).^[2]

antidepressants

¹⁾ Kennedy, S. H., Lam, R. W., McIntyre, R. S., Tourjman, S. V., Bhat, V., Blier, P., ... & CANMAT Depression Work Group. (2016). Canadian Network for Mood and Anxiety Treatments (CANMAT) 2016 clinical guidelines for the management of adults with major depressive disorder: section 3. Pharmacological treatments. The Canadian Journal of Psychiatry, 61(9), 540-560.

²⁾ Huybrechts, K. F., Bateman, B. T., Palmsten, K., Desai, R. J., Patorno, E., Gopalakrishnan, C., ... & Hernandez-Diaz, S. (2015). Antidepressant use late in pregnancy and risk of persistent pulmonary hypertension of the newborn. Jama, 313(21), 2142-2151.

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