In Collaboration With

THERAPEUTICS

Brands

• Celexa
• see index for additional brand names

Generic?

• Yes

Class

• SSRI (selective serotonin reuptake inhibitor); often classified as an antidepressant, but it is not just an antidepressant

Commonly Prescribed For

• (bold for FDA approved)
• Depression
• Premenstrual dysphoric disorder (PMDD)
• Obsessive-compulsive disorder (OCD)
• Panic disorder
• Generalized anxiety disorder
• Posttraumatic stress disorder (PTSD)
• Social anxiety disorder (social phobia)

How The Drug Works

• Boosts neurotransmitter serotonin
• Blocks serotonin reuptake pump (serotonin transporter)
• Desensitizes serotonin receptors, especially serotonin 1A autoreceptors
• Presumably increases serotonergic neurotransmission
• Citalopram also has mild antagonist actions at H1 histamine receptors
• Citalopram’s inactive R enantiomer may interfere with the therapeutic actions of the active S enantiomer at serotonin reuptake pumps

How Long Until It Works

• Onset of therapeutic actions usually not immediate, but often delayed 2 to 4 weeks
• If it is not working within 6 to 8 weeks, it may require a dosage increase or it may not work at all
• May continue to work for many years to prevent relapse of symptoms

If It Works

• The goal of treatment is complete remission of current symptoms as well as prevention of future relapses
• Treatment most often reduces or even eliminates symptoms, but not a cure since symptoms can recur after medicine stopped
• Continue treatment until all symptoms are gone (remission) or significantly reduced (e.g., OCD, PTSD)
• Once symptoms are gone, continue treating for 1 year for the first episode of depression
• For second and subsequent episodes of depression, treatment may need to be indefinite
• Use in anxiety disorders may also need to be indefinite

If It Doesn’t Work

• Many patients only have a partial response where some symptoms are improved but others persist (especially insomnia, fatigue, and problems concentrating in depression)
• Other patients may be nonresponders, sometimes called treatment-resistant or treatment-refractory
• Some patients who have an initial response may relapse even though they continue treatment, sometimes called “poop-out”
• Consider increasing dose, switching to another agent or adding an appropriate augmenting agent
• Consider psychotherapy
• Consider evaluation for another diagnosis or for a comorbid condition (e.g., medical illness, substance abuse, etc.)
• Some patients may experience apparent lack of consistent efficacy due to activation of latent or underlying bipolar disorder, and require antidepressant discontinuation and a switch to a mood stabilizer

Best Augmenting Combos for Partial Response or Treatment-Resistance

• Trazodone, especially for insomnia
• Bupropion, mirtazapine, reboxetine, or atomoxetine (add with caution and at lower doses since citalopram could theoretically raise atomoxetine levels); use combinations of antidepressants with caution as this may activate bipolar disorder and suicidal ideation
• Modafinil, especially for fatigue, sleepiness, and lack of concentration
• Mood stabilizers or atypical antipsychotics for bipolar depression, psychotic depression, treatment-resistant depression, or treatment-resistant anxiety disorders
• Benzodiazepines
• If all else fails for anxiety disorders, consider gabapentin or tiagabine
• Hypnotics for insomnia
• Classically, lithium, buspirone, or thyroid hormone

Tests

• None for healthy individuals