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Citalopram
Aka: Citalopram, Celexa, Escitalopram, Lexapro, Citalopram Overdose
- Mechanism
- Selective Serotonin Reuptake Inhibitor (SSRI)
- Minimal effects on other Neurotransmitters
- Pharmacokinetics
- Half-life: 20 to 35 hours
- Bioavailability: 80%
- Peak drug levels: 4 hours
- Indications
- Major Depression
- Preparations
- Citalopram (Celexa)
- Tablets: 10, 20 (scored), 40 (scored)
- Oral Solution: 10 mg/5 ml
- Escitalopram (Lexapro)
- Active isomer of racemic Citalopram
- Tablets: 5, 10 (scored), 20 mg (scored)
- Dosing
- Citalopram (Celexa)
- Starting dose: 20 mg PO qd
- Most effective dose: 40 mg PO qd
- Maximum Dose: 40 mg
- Escitalopram (Lexapro)
- Starting Dose: 10 mg qd (equivalent to 40 mg Celexa)
- Higher dose at 20 mg is not more effective than 10 mg
- Adverse Effects: General
- No increased weight gain
- Midway on spectrum between Anxiolytic and anxiogenic
- Similar to Zoloft on this spectrum
- Well tolerated
- Nausea
- May occur initially but is transient
- Consider decreasing dose to 10 mg initially
- Less Sexual Dysfunction than Prozac, Zoloft, Paxil
- Sexual Dysfunction in 10-15% of cases
- Similar to Luvox and Effexor in terms of this effect
- See Antidepressant Induced Sexual Dysfunction
- Adverse Effects: Overdose
- See SSRI Overdose
- P450 Metabolism to di-desmethylcitalopram
- Di-desmethylcitalopram is cardiotoxic (inhibits cardiac Potassium and Calcium channels)
- Overdose presentation (esp. ingestions >600 mg)
- Sedation
- Seizures
- Tachycardia
- QT Prolongation
- Torsades de Pointes
- Metabolic Acidosis
- Hypokalemia
- Evaluation and Management
- See SSRI Overdose
- See Serotonin Syndrome
- See Unknown Ingestion
- Monitoring
- Asymptomatic
- Monitor up to 12 hours if suspected ingestion >400 mg
- Symptomatic or QTc Prolongation
- Monitor until resolution of symptoms and QTc normalization
- References
- Tomszewski (2021) Crit Dec Emerg Med 35(12): 32
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Drug Interactions
- Cytochrome P450 2C19 Inhibitors
- Arrhythmia risk: Prolonged QT interval and Torsades de Pointes risk
- Most significant agents
- Proton Pump Inhibitors: Omeprazole, Esomeprazole
- Ethinyl Estradiol (Oral Contraceptives)
- Agents that do not appear to have significant interactions
- Proton Pump Inhibitors: Pantoprazole, Lansoprazole, Dexlansoprazole
- Precautions
- Limit Citalopram to 20 mg daily in those on Omeprazole, Esomeprazole, Oral Contraceptives
- Consider Escitalopram (Lexapro) instead which appears safe to at least 20 mg daily with these agents
- Resources
- FDA Drug Safety Notice
- http://www.fda.gov/Drugs/DrugSafety/ucm269086.htm
- Resources
- Celexa Website (Forest Pharmaceuticals)
- http://www.celexa.com