Pharm
Citalopram
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Citalopram
, Celexa, Escitalopram, Lexapro, Citalopram Overdose
Mechanism
Selective Serotonin Reuptake Inhibitor
(
SSRI
)
Minimal effects on other
Neurotransmitter
s
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
Gene
ral
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
Seizure
s
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
Drug Interactions
Cytochrome P450
2C19 Inhibitors
Arrhythmia
risk:
Prolonged QT
interval and
Torsades de Pointes
risk
Most significant agents
Proton Pump Inhibitor
s:
Omeprazole
,
Esomeprazole
Ethinyl Estradiol
(
Oral Contraceptive
s)
Agents that do not appear to have significant interactions
Proton Pump Inhibitor
s:
Pantoprazole
,
Lansoprazole
,
Dexlansoprazole
Precautions
Limit Citalopram to 20 mg daily in those on
Omeprazole
,
Esomeprazole
,
Oral Contraceptive
s
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
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