Citalopram

Drug Interactions Serotonergic Drugs See CONTRAINDICATIONS , WARNINGS , and DOSAGE AND ADMINISTRATION . Triptans There have been rare postmarketing reports of serotonin syndrome with use of an SSRI and a triptan. If concomitant treatment of citalopram with a triptan is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases(see WARNINGS - Serotonin Syndrome ). CNS Drugs Given the primary CNS effects of citalopram, caution should be used when it is taken in combination with other centrally acting drugs. Alcohol Although citalopram did not potentiate the cognitive and motor effects of alcohol in a clinical trial, as with other psychotropic medications, the use of alcohol by depressed patients taking citalopram is not recommended. Monoamine Oxidase Inhibitors (MAOIs) - See CONTRAINDICATIONS , WARNINGS and DOSAGE AND ADMINISTRATION . Drugs That Interfere With Hemostasis (NSAIDs, Aspirin, Warfarin, etc.) Serotonin release by platelets plays an important role in hemostasis. Epidemiological studies of the case-control and cohort design that have demonstrated an association between use of psychotropic drugs that interfere with serotonin reuptake and the occurrence of upper gastrointestinal bleeding have also shown that concurrent use of an NSAID or aspirin may potentiate the risk of bleeding. Altered anticoagulant effects, including increased bleeding, have been reported when SSRIs and SNRIs are coadministered with warfarin. Patients receiving warfarin therapy should be carefully monitored when citalopram is initiated or discontinued. Cimetidine In subjects who had received 21 days of 40 mg/day citalopram, combined administration of 400 mg twice a day cimetidine for 8 days resulted in an increase in citalopram AUC and C max of 43% and 39%, respectively. Citalopram 20 mg/day is the maximum recommended dose for patients taking concomitant cimetidine because of the risk of QT prolongation (see WARNINGS and DOSAGE AND ADMINISTRATION ). Digoxin In subjects who had received 21 days of 40 mg/day citalopram, combined administration of citalopram and digoxin (single dose of 1 mg) did not significantly affect the pharmacokinetics of either citalopram or digoxin. Lithium Coadministration of citalopram (40 mg/day for 10 days) and lithium (30 mmol/day for 5 days) had no significant effect on the pharmacokinetics of citalopram or lithium. Nevertheless, plasma lithium levels should be monitored with appropriate adjustment to the lithium dose in accordance with standard clinical practice. Because lithium may enhance the serotonergic effects of citalopram, caution should be exercised when citalopram and lithium are coadministered. Pimozide In a controlled study, a single dose of pimozide 2 mg co-administered with citalopram 40 mg given once daily for 11 days was associated with a mean increase in QTc values of approximately 10 msec compared to pimozide given alone. Citalopram did not alter the mean AUC or C max of pimozide. The mechanism of this pharmacodynamic interaction is not known. Theophylline Combined administration of citalopram (40 mg/day for 21 days) and the CYP1A2 substrate theophylline (single dose of 300 mg) did not affect the pharmacokinetics of theophylline. The effect of theophylline on the pharmacokinetics of citalopram was not evaluated. Sumatriptan There have been rare postmarketing reports describing patients with weakness, hyperreflexia, and incoordination following the use of a SSRI and sumatriptan. If concomitant treatment with sumatriptan and an SSRI (e.g., fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram) is clinically warranted, appropriate observation of the patient is advised. Warfarin Administration of 40 mg/day citalopram for 21 days did not affect the pharmacokinetics of warfarin, a CYP3A4 substrate. Prothrombin time was increased by 5%, the clinical significance of which is unknown. Carbamazepine Combined administration of citalopram (40 mg/day for 14 days) and carbamazepine (titrated to 400 mg/day for 35 days) did not significantly affect the pharmacokinetics of carbamazepine, a CYP3A4 substrate. Although trough citalopram plasma levels were unaffected, given the enzyme-inducing properties of carbamazepine, the possibility that carbamazepine might increase the clearance of citalopram should be considered if the two drugs are coadministered. Triazolam Combined administration of citalopram (titrated to 40 mg/day for 28 days) and the CYP3A4 substrate triazolam (single dose of 0.25 mg) did not significantly affect the pharmacokinetics of either citalopram or triazolam. Ketoconazole Combined administration of citalopram (40 mg) and ketoconazole (200 mg) decreased the C max and AUC of ketoconazole by 21% and 10%, respectively, and did not significantly affect the pharmacokinetics of citalopram. CYP2C19 Inhibitors Citalopram 20 mg/day is the maximum recommended dose for patients taking concomitant CYP2C19 inhibitors because of the risk of QT prolongation (see WARNINGS , DOSAGE AND ADMINISTRATION , AND CLINICAL PHARMACOLOGY ). Metoprolol Administration of 40 mg/day citalopram for 22 days resulted in a two-fold increase in the plasma levels of the beta-adrenergic blocker metoprolol. Increased metoprolol plasma levels have been associated with decreased cardioselectivity. Coadministration of citalopram and metoprolol had no clinically significant effects on blood pressure or heart rate. Imipramine and Other Tricyclic Antidepressants (TCAs) In vitro studies suggest that citalopram is a relatively weak inhibitor of CYP2D6. Coadministration of citalopram (40 mg/day for 10 days) with the TCA imipramine (single dose of 100 mg), a substrate for CYP2D6, did not significantly affect the plasma concentrations of imipramine or citalopram. However, the concentration of the imipramine metabolite desipramine was increased by approximately 50%. The clinical significance of the desipramine change is unknown. Nevertheless, caution is indicated in the coadministration of TCAs with citalopram. Electroconvulsive Therapy (ECT) There are no clinical studies of the combined use of electroconvulsive therapy (ECT) and citalopram.

"Citalopram tablets are indicated for the treatment of major depressive disorder (MDD) in adults." The medication is not approved for pediatric use.

DOSAGE AND ADMINISTRATION Citalopram tablets, USP should be administered once daily, in the morning or evening, with or without food. Initial Treatment Citalopram tablets, USP should be administered at an initial dose of 20 mg once daily, with an increase to a maximum dose of 40 mg/day at an interval of no less than one week. Doses above 40 mg/day are not recommended due to the risk of QT prolongation. Additionally, the only study pertinent to dose response for effectiveness did not demonstrate an advantage for the 60 mg/day dose over the 40 mg/day dose. Special Populations 20 mg/day is the maximum recommended dose for patients who are greater than 60 years of age, patients with hepatic impairment, and for CYP2C19 poor metabolizers or those patients taking cimetidine or another CYP2C19 inhibitor. (see WARNINGS ) No dosage adjustment is necessary for patients with mild or moderate renal impairment. Citalopram should be used with caution in patients with severe renal impairment. Treatment of Pregnant Women During the Third Trimester Neonates exposed to citalopram and other SSRIs or SNRIs, late in the third trimester, have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding (see PRECAUTIONS ). When treating pregnant women with citalopram tablets during the third trimester, the physician should carefully consider the potential risks and benefits of treatment. Maintenance Treatment It is generally agreed that acute episodes of depression require several months or longer of sustained pharmacologic therapy. Systematic evaluation of citalopram in two studies has shown that its antidepressant efficacy is maintained for periods of up to 24 weeks following 6 or 8 weeks of initial treatment (32 weeks total). In one study, patients were assigned randomly to placebo or to the same dose of citalopram (20 to 60 mg/day) during maintenance treatment as they had received during the acute stabilization phase, while in the other study, patients were assigned randomly to continuation of citalopram 20 or 40 mg/day, or placebo, for maintenance treatment. In the latter study, the rates of relapse to depression were similar for the two dose groups (see Clinical Trials under CLINICAL PHARMACOLOGY ). Based on these limited data, it is not known whether the dose of citalopram needed to maintain euthymia is identical to the dose needed to induce remission. If adverse reactions are bothersome, a decrease in dose to 20 mg/day can be considered. Discontinuation of Treatment with Citalopram Tablets, USP Symptoms associated with discontinuation of citalopram and other SSRIs and SNRIs have been reported (see PRECAUTIONS ). Patients should be monitored for these symptoms when discontinuing treatment. A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the physician may continue decreasing the dose but at a more gradual rate. Switching Patients To or From a Monoamine Oxidase Inhibitor (MAOI) Intended to Treat Psychiatric Disorders At least 14 days should elapse between discontinuation of an MAOI intended to treat psychiatric disorders and initiation of therapy with citalopram. Conversely, at least 14 days should be allowed after stopping citalopram before starting an MAOI intended to treat psychiatric disorders (see CONTRAINDICATIONS ). Use of Citalopram with Other MAOIs, Such as Linezolid or Methylene Blue Do not start citalopram in a patient who is being treated with linezolid or intravenous methylene blue because there is an increased risk of serotonin syndrome. In a patient who requires more urgent treatment of a psychiatric condition, other interventions, including hospitalization, should be considered (see CONTRAINDICATIONS ). In some cases, a patient already receiving citalopram therapy may require urgent treatment with linezolid or intravenous methylene blue. If acceptable alternatives to linezolid or intravenous methylene blue treatment are not available and the potential benefits of linezolid or intravenous methylene blue treatment are judged to outweigh the risks of serotonin syndrome in a particular patient, citalopram should be stopped promptly, and linezolid or intravenous methylene blue can be administered. The patient should be monitored for symptoms of serotonin syndrome for 2 weeks or until 24 hours after the last dose of linezolid or intravenous methylene blue, whichever comes first. Therapy with citalopram may be resumed 24 hours after the last dose of linezolid or intravenous methylene blue (see WARNINGS ). The risk of administering methylene blue by non-intravenous routes (such as oral tablets or by local injection) or in intravenous doses much lower than 1 mg/kg with citalopram is unclear. The clinician should, nevertheless, be aware of the possibility of emergent symptoms of serotonin syndrome with such use (see WARNINGS ).

The most frequent adverse reaction occurring in ≥5% of patients and at least twice placebo rate was "ejaculation disorder (primarily ejaculatory delay)" in males. Other common reactions (≥5%): nausea, dry mouth, somnolence, tremor, insomnia, fatigue, and increased sweating.