Pharm

Citalopram

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Citalopram, Celexa, Escitalopram, Lexapro

  • Mechanism
  1. Selective Serotonin Reuptake Inhibitor (SSRI)
  2. Minimal effects on other Neurotransmitters
  • Pharmacokinetics
  1. Half-life: 20 hours
  • Indications
  1. Major Depression
  • Preparations
  1. Citalopram (Celexa)
    1. Tablets: 10, 20 (scored), 40 (scored)
    2. Oral Solution: 10 mg/5 ml
  2. Escitalopram (Lexapro)
    1. Active isomer of racemic Citalopram
    2. Tablets: 5, 10 (scored), 20 mg (scored)
  • Dosing
  1. Citalopram (Celexa)
    1. Starting dose: 20 mg PO qd
    2. Most effective dose: 40 mg PO qd
    3. Maximum Dose: 40 mg
  2. Escitalopram (Lexapro)
    1. Starting Dose: 10 mg qd (equivalent to 40 mg Celexa)
    2. Higher dose at 20 mg is not more effective than 10 mg
  • Adverse Effects
  1. No increased weight gain
  2. Midway on spectrum between Anxiolytic and anxiogenic
    1. Similar to Zoloft on this spectrum
    2. Well tolerated
  3. Nausea
    1. May occur initially but is transient
    2. Consider decreasing dose to 10 mg initially
  4. Less Sexual Dysfunction than Prozac, Zoloft, Paxil
    1. Sexual Dysfunction in 10-15% of cases
    2. Similar to Luvox and Effexor in terms of this effect
    3. See Antidepressant Induced Sexual Dysfunction
  • Drug Interactions
  1. Cytochrome P450 2C19 Inhibitors
    1. Arrhythmia risk: Prolonged QT interval and Torsades de Pointes risk
    2. Most significant agents
      1. Proton Pump Inhibitors: Omeprazole, Esomeprazole
      2. Ethinyl Estradiol (Oral Contraceptives)
    3. Agents that do not appear to have significant interactions
      1. Proton Pump Inhibitors: Pantoprazole, Lansoprazole, Dexlansoprazole
    4. Precautions
      1. Limit Citalopram to 20 mg daily in those on Omeprazole, Esomeprazole, Oral Contraceptives
      2. Consider Escitalopram (Lexapro) instead which appears safe to at least 20 mg daily with these agents
    5. Resources
      1. FDA Drug Safety Notice
        1. http://www.fda.gov/Drugs/DrugSafety/ucm269086.htm
  • Resources
  1. Celexa Website (Forest Pharmaceuticals)
    1. http://www.celexa.com