Usage
- Citalopram is primarily prescribed for the treatment of major depressive disorder (MDD). It is also used off-label for conditions such as panic disorder, obsessive-compulsive disorder (OCD), premenstrual dysphoric disorder (PMDD), generalized anxiety disorder (GAD), and post-traumatic stress disorder (PTSD).
- Pharmacological classification: Selective serotonin reuptake inhibitor (SSRI).
- Mechanism of Action: Citalopram selectively inhibits the reuptake of serotonin, a neurotransmitter, in the synaptic cleft, increasing its concentration and enhancing serotonergic neurotransmission in the brain.
Alternate Names
- International and regional variations: Citalopram hydrobromide (USAN)
- Brand names: Celexa, Cipramil
How It Works
- Pharmacodynamics: Citalopram primarily exerts its therapeutic effect by increasing serotonin levels in the brain. The increase in serotonin availability at the synaptic cleft leads to enhanced serotonergic neurotransmission.
- Pharmacokinetics: Citalopram is well-absorbed orally, reaching peak plasma concentrations within 2-4 hours. It undergoes hepatic metabolism, primarily via CYP2C19, with a half-life of approximately 35 hours. It is primarily eliminated through renal excretion.
- Mode of Action: Citalopram selectively binds to the serotonin transporter (SERT) protein, inhibiting the reuptake of serotonin from the synaptic cleft. This results in increased serotonin concentrations in the synaptic cleft, enhancing serotonergic neurotransmission. Citalopram has minimal affinity for other receptors, such as dopamine, norepinephrine, or histamine receptors, contributing to its selectivity.
- Elimination Pathways: Primarily renal excretion of metabolites, with a small fraction excreted in the feces. Hepatic metabolism involves CYP2C19, CYP3A4, and CYP2D6 enzymes.
Dosage
Standard Dosage
Adults:
- Initial dose: 20 mg orally once daily.
- Maintenance dose: May be increased to a maximum of 40 mg/day (up to 60 mg/day in some cases for OCD) after at least one week, based on individual patient response.
- Administration: Oral, once daily with or without food.
Children:
- Use and dose must be determined by a doctor.
- Safety and efficacy in children younger than 18 have not been fully established.
Special Cases:
- Elderly Patients (over 65 years): Initial dose of 10mg daily, potentially increasing to a maximum of 20 mg daily.
- Patients with Renal Impairment: No dosage adjustment is necessary for mild to moderate renal impairment. Caution is advised in severe renal impairment (CrCl < 20 mL/min).
- Patients with Hepatic Dysfunction: Maximum dose of 20 mg/day due to decreased clearance.
- Patients with Comorbid Conditions: Careful monitoring and potential dosage adjustments may be required.
Clinical Use Cases
Citalopram’s primary indication is major depressive disorder. Other uses are off-label. Dosages may vary depending on the condition being treated. Its use is not typically indicated in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. For these situations, other medications may be more appropriate.
Dosage Adjustments
- Dose reduction may be necessary for patients with hepatic impairment, renal impairment, elderly patients, and poor CYP2C19 metabolizers.
Side Effects
Common Side Effects
- Nausea, dry mouth, insomnia, somnolence, increased sweating, tremor, diarrhea, and sexual dysfunction.
Rare but Serious Side Effects
- Serotonin syndrome, hyponatremia, increased risk of bleeding, QT prolongation, mania/hypomania, suicidal ideation, and seizures.
Long-Term Effects
- Potential for sexual dysfunction, weight gain, and withdrawal symptoms upon discontinuation.
Adverse Drug Reactions (ADR)
- Serotonin syndrome, QTc interval prolongation, and severe hyponatremia require immediate medical attention.
Contraindications
- Known hypersensitivity to citalopram or any of its components.
- Concomitant use with MAOIs or within 14 days of discontinuing MAOIs.
- Patients receiving methylene blue or linezolid.
Drug Interactions
- MAOIs, pimozide, other serotonergic drugs (e.g., SSRIs, SNRIs, tricyclic antidepressants), drugs that prolong the QT interval (e.g., antiarrhythmics), CYP2C19 inhibitors (e.g., cimetidine, omeprazole), anticoagulants, and antiplatelet agents.
- Alcohol may increase the risk of CNS depression.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: C (FDA). Use only if the potential benefit outweighs the potential risk to the fetus.
- Citalopram is excreted in breast milk. Potential neonatal effects include irritability, poor feeding, and respiratory distress. Monitor infants exposed to citalopram through breast milk.
Drug Profile Summary
- Mechanism of Action: Selective serotonin reuptake inhibitor (SSRI).
- Side Effects: Nausea, dry mouth, insomnia, somnolence, sexual dysfunction (common); Serotonin syndrome, QT prolongation, suicidal ideation (serious).
- Contraindications: Hypersensitivity, concurrent MAOI use, methylene blue or linezolid treatment.
- Drug Interactions: MAOIs, pimozide, other serotonergic drugs, CYP2C19 inhibitors.
- Pregnancy & Breastfeeding: Category C; excreted in breast milk, monitor infant.
- Dosage: Adults: 20-40mg/day; Elderly/Hepatically impaired: Max 20mg/day; Pediatrics: Consult doctor.
- Monitoring Parameters: Monitor for mood changes, suicidal ideation, and serotonin syndrome. Electrocardiogram (ECG) monitoring may be necessary in some patients.
Popular Combinations
- Citalopram is sometimes combined with other medications for treatment-resistant depression or other specific symptoms, though it’s important to be aware of potential interactions. Combining citalopram with other serotonergic drugs can increase the risk of serotonin syndrome, which can be life-threatening.
Precautions
- General Precautions: Assess for suicidal ideation, monitor for serotonin syndrome, and screen for bipolar disorder before starting treatment.
- Specific Populations: Dosage adjustments may be necessary for elderly patients and those with hepatic or renal impairment. Caution in pregnancy and breastfeeding.
- Lifestyle Considerations: Limit alcohol consumption. Driving and operating machinery may be impaired.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Citalopram?
A: Adults: Initially 20 mg once daily, which can be increased to a maximum of 40 mg/day (up to 60 mg/day in some cases for OCD) after at least one week. Elderly/Hepatically Impaired: Maximum 20 mg/day. Pediatric patients: Use and dosage must be determined by a doctor.
Q2: What are the most common side effects of Citalopram?
A: The most common side effects include nausea, dry mouth, insomnia, somnolence, increased sweating, tremor, and sexual dysfunction.
Q3: How does Citalopram work?
A: It selectively inhibits the reuptake of serotonin, increasing serotonin levels in the brain synapses.
Q4: Are there any contraindications for Citalopram use?
A: Yes. Contraindications include hypersensitivity to Citalopram, concurrent use of MAOIs, and use with methylene blue or linezolid.
Q5: Can Citalopram be used during pregnancy?
A: Citalopram is a Pregnancy Category C drug. Use only if the potential benefit outweighs the potential risk to the fetus. Consult with a specialist.
Q6: Does Citalopram interact with other medications?
A: Yes. Significant interactions can occur with MAOIs, pimozide, other serotonergic drugs, CYP2C19 inhibitors, and drugs that prolong the QT interval.
Q7: What should I monitor in patients taking Citalopram?
A: Monitor for mood changes, especially suicidal ideation or worsening depression, as well as for signs of serotonin syndrome. ECG monitoring may be indicated in some patients.
Q8: What are the symptoms of Citalopram overdose?
A: Symptoms can include dizziness, fast heartbeat, nausea and vomiting, sleepiness, sweating, and tremors.
Q9: Can Citalopram be stopped abruptly?
A: No, it’s generally recommended to taper off Citalopram gradually to minimize withdrawal symptoms.
