CITALOPRAM HYDROBROMIDE
Clinical safety rating: caution
MAOIs can cause serotonin syndrome and other SSRIs may have additive effects Causes dose-dependent QT prolongation.
Selective serotonin reuptake inhibitor (SSRI); inhibits CNS neuronal reuptake of serotonin (5-HT) with negligible effects on norepinephrine or dopamine reuptake, potentiating serotonergic activity in the CNS.
| Metabolism | Primarily hepatic via CYP3A4 and CYP2C19; minor contributions from CYP2D6; forms metabolites including desmethylcitalopram (active) and didesmethylcitalopram. |
| Excretion | Renal (approximately 75% as metabolites, 12-23% as unchanged drug) and fecal (approximately 10%). |
| Half-life | Terminal elimination half-life is approximately 35 hours (range 24-48 hours), supporting once-daily dosing; linear pharmacokinetics at therapeutic doses. |
| Protein binding | Approximately 80% bound to plasma proteins (mainly albumin and alpha-1-acid glycoprotein). |
| Volume of Distribution | 12-16 L/kg, indicating extensive extravascular distribution; high tissue penetration, including CNS. |
| Bioavailability | Oral bioavailability is approximately 80% (range 60-90%), with minimal first-pass metabolism. |
| Onset of Action | Oral: Initial antidepressant effects may be noted within 1-2 weeks, with full therapeutic benefit typically requiring 4-6 weeks. For anxiety disorders, onset may be within 1-2 weeks. |
| Duration of Action | Sustained 24-hour coverage with once-daily dosing due to long half-life; steady-state achieved in 1-2 weeks. Withdrawal effects may occur if abruptly discontinued after prolonged use. |
20 mg orally once daily, initially; may increase to 40 mg orally once daily after minimum 1 week. Maximum dose 40 mg orally once daily.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Severe renal impairment (CrCl <20 mL/min): use not recommended; if necessary, maximum 20 mg orally once daily. |
| Liver impairment | Mild to moderate hepatic impairment (Child-Pugh A or B): maximum 20 mg orally once daily. Severe hepatic impairment (Child-Pugh C): use not recommended. |
| Pediatric use | Not approved for pediatric use in major depressive disorder. For obsessive-compulsive disorder (adolescents 13-17 years): initial 20 mg orally once daily, may increase to 40 mg orally once daily after minimum 2 weeks. |
| Geriatric use | Initial 10 mg orally once daily, with maximum 20 mg orally once daily. Titrate slowly. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
MAOIs can cause serotonin syndrome and other SSRIs may have additive effects Causes dose-dependent QT prolongation.
| FDA category | Animal |
| Breastfeeding | Citalopram is excreted into breast milk with a milk-to-plasma ratio (M/P) of approximately 1.8 (range 0.4–3.0). Relative infant dose is about 4–5% of maternal weight-adjusted dose. Cases of excessive somnolence, poor feeding, and colic in breastfed infants have been reported. The American Academy of Pediatrics considers citalopram compatible with breastfeeding, but monitor infant for sedation and weight gain. Benefits generally outweigh risks for postpartum depression. |
■ FDA Black Box Warning
Increased risk of suicidal thinking and behavior in children, adolescents, and young adults (aged 18-24) during initial treatment; monitor closely for clinical worsening and suicidality.
| Common Effects | Nausea |
| Serious Effects |
["Concurrent use with MAOIs (including linezolid or IV methylene blue)","Concurrent use with pimozide","Known hypersensitivity to citalopram or escitalopram","QTc interval >500 msec or congenital long QT syndrome","Uncontrolled electrolyte disturbances (hypokalemia, hypomagnesemia)"]
| Precautions | ["QT interval prolongation (dose-dependent; avoid doses >40 mg/day)","Serotonin syndrome (risk with concurrent serotonergic drugs)","Hyponatremia (especially elderly or volume-depleted)","Activation of mania/hypomania","Seizure threshold lowering","Angle-closure glaucoma","SIADH","Abrupt discontinuation syndrome","Increased bleeding risk (with NSAIDs/aspirin)"] |
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| Teratogenic Risk |
| First trimester: Retrospective studies suggest a small increased risk of cardiac malformations (primarily ventricular septal defects) with maternal use; absolute risk increase <1%. Second trimester: No consistent evidence of increased major malformations. Third trimester: Risk of persistent pulmonary hypertension of the newborn (PPHN) (odds ratio ~1.5) and neonatal adaptation syndrome (irritability, feeding difficulties, respiratory distress) with late exposure. Overall, risk is low but not zero. |
| Fetal Monitoring | Maternal: Assess for worsening depression, suicidal ideation, and serotonin syndrome symptoms (agitation, hyperthermia, clonus). Fetal: Consider detailed fetal echocardiography at 18–22 weeks if first-trimester exposure. Neonatal: Monitor for adaptation syndrome (irritability, tremor, respiratory distress) for 2–4 days postpartum. Evaluate for persistent pulmonary hypertension if third-trimester exposure. |
| Fertility Effects | No significant impairment of fertility in animal studies. In humans, citalopram may cause hyperprolactinemia (rare), potentially affecting ovulation by disrupting hypothalamic-pituitary-gonadal axis. Limited data suggest no substantial impact on female fertility. For males, SSRIs may reduce sperm motility and concentration, but data are inconsistent; effects reverse upon discontinuation. |