Overview
11 DESCRIPTION Citalopram tablets, USP contains citalopram, a selective serotonin reuptake inhibitor (SSRI). Citalopram hydrobromide is a racemic bicyclic phthalane structure and is designated (±)-1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-carbonitrile hydrobromide with the following structural formula: The molecular formula is C 20 H 22 BrFN 2 O and its molecular...
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The mechanism of action of citalopram is unclear, but is presumed to be related to potentiation of serotonergic activity in the central nervous system (CNS) resulting from its inhibition of CNS neuronal reuptake of serotonin (5-HT). 12.2 Pharmacodynamics In vitro and in vivo studies in animals suggest that citalopram is a selective serotonin reuptake inhibitor (SSRI) with minimal effects on norepinephrine (NE) and dopamine (DA) neuronal reuptake. Citalopram has no or very low affinity for 5-HT 1A , 5-HT 2A , dopamine D 1 and D 2 , α 1 -, α 2 -, and β-adrenergic, histamine H 1 , gamma aminobutyric acid (GABA), muscarinic cholinergic, and benzodiazepine receptors.
Indications
- 1 INDICATIONS AND USAGE Citalopram tablets are indicated for the treatment of major depressive disorder (MDD) in adults [see Clinical Studies (14) ] . Citalopram tablets are a selective serotonin reuptake inhibitor (SSRI) indicated for the treatment of major depressive disorder (MDD) in adults ( 1 ) .
Common Doses
- 20 mg
- 40 mg
Dosage
2 DOSAGE AND ADMINISTRATION Administer once daily with or without food ( 2 ) . Initial dosage is 20 mg once daily; after one week may increase to maximum dosage of 40 mg once daily ( 2.1 ). Patients greater than 60 years of age, patients with hepatic impairment, and CYP2C19 poor metabolizers: maximum recommended dosage is 20 mg once daily ( 2.2 ). When discontinuing citalopram tablets, reduce dosage gradually ( 2.4 , 5.6 ). 2.
Black Box Warning
WARNING: SUICIDAL THOUGHTS AND BEHAVIORS Antidepressants increased the risk of suicidal thoughts and behaviors in pediatric and young adult patients in short-term studies. Closely monitor all antidepressant-treated patients for clinical worsening, and for emergence of suicidal thoughts and behaviors [see Warnings and Precautions (5.1) ] . Citalopram is not approved for use in pediatric patients [see Use in Specific Populations (8.4) ]. WARNING: SUICIDAL THOUGHTS AND BEHAVIORS See full prescribing information for complete boxed warning.
Contraindications
- 4 CONTRAINDICATIONS Citalopram tablets are contraindicated in patients: taking, or within 14 days of stopping, MAOIs (including MAOIs such as linezolid or intravenous methylene blue) because of an increased risk of serotonin syndrome [see Warnings and Precautions (5.3) , Drug Interactions (7) ] . taking pimozide because of risk of QT prolongation [see Drug Interactions (7) ] . with known hypersensitivity to citalopram or any of the inactive ingredients in citalopram tablets. Reactions have included angioedema and anaphylaxis [see Adverse Reactions (6.2) ].
Side Effects
- 6 ADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the labeling: Hypersensitivity reactions [see Contraindications (4) ] Suicidal thoughts and behaviors in adolescents and young adults [see Warnings and Precautions (5.1) ] QT-prolongation and torsade de pointes [see Warnings and Precautions (5.2) ] Serotonin syndrome [see Warnings and Precautions (5.3) ] Increased risk of bleeding [see Warnings and Precautions (5.4) ] Activation of mania or hypomania [see Warnings and Precautions (5.
Interactions
- 7 DRUG INTERACTIONS Table 5 presents clinically important drug interactions with citalopram. Table 5: Clinically Important Drug Interactions with Citalopram Monoamine Oxidase Inhibitors (MAOIs) Clinical Impact Concomitant use of SSRIs, including citalopram, and MAOIs increases the risk of serotonin syndrome. Intervention Citalopram is contraindicated in patients taking MAOIs, including MAOIs such as linezolid or intravenous methylene blue [see Dosage and Administration (2.5) , Contraindications (4) , Warnings and Precautions (5.3) ] .