Selective serotonin reuptake inhibitors

Selective serotonin reuptake inhibitors (SSRIs) are considered first-line treatment for the majority of patients with depression.

• citalopram (although see below re: QT interval) and fluoxetine are currently the preferred SSRIs
• sertraline is useful post myocardial infarction as there is more evidence for its safe use in this situation than other antidepressants
• SSRIs should be used with caution in children and adolescents. Fluoxetine is the drug of choice when an antidepressant is indicated

Adverse effects

• gastrointestinal symptoms are the most common side-effect
• there is an increased risk of gastrointestinal bleeding in patients taking SSRIs. A proton pump inhibitor should be prescribed if a patient is also taking a NSAID
• patients should be counselled to be vigilant for increased anxiety and agitation after starting a SSRI
• fluoxetine and paroxetine have a higher propensity for drug interactions

Citalopram and the QT interval

• the Medicines and Healthcare products Regulatory Agency (MHRA) released a warning on the use of citalopram in 2011
• it advised that citalopram and escitalopram are associated with dose-dependent QT interval prolongation and should not be used in those with: congenital long QT syndrome; known pre-existing QT interval prolongation; or in combination with other medicines that prolong the QT interval
• the maximum daily dose is now 40 mg for adults; 20 mg for patients older than 65 years; and 20 mg for those with hepatic impairment

Interactions

• NSAIDs: NICE guidelines advise 'do not normally offer SSRIs', but if given co-prescribe a proton pump inhibitor
• warfarin / heparin: NICE guidelines recommend avoiding SSRIs and considering mirtazapine
• aspirin
• triptans - increased risk of serotonin syndrome
• monoamine oxidase inhibitors (MAOIs) - increased risk of serotonin syndrome