“If this blog helped you out, don’t keep it to yourself—share the link on your socials!” 👍 “Like what you read? Spread the love and share this blog on your social media.” 👍 “Found this useful? Hit share and let your friends know too!” 👍 “If you enjoyed this post, please share the URL with your friends online.” 👍 “Sharing is caring—drop this link on your social media if it helped you.”

Sunday, July 27, 2025

Citalopram


Citalopram is a selective serotonin reuptake inhibitor (SSRI) antidepressant that is primarily prescribed to treat major depressive disorder (MDD) and sometimes generalized anxiety disorder (GAD), panic disorder, and obsessive-compulsive disorder (OCD). It is considered one of the first-line pharmacologic treatments for depression due to its relatively favorable side effect profile and safety in overdose compared to older classes like tricyclic antidepressants or monoamine oxidase inhibitors (MAOIs). Citalopram is administered orally and is available in tablet and oral solution formulations.

This comprehensive reference outlines its classification, mechanism, clinical uses, dosing, contraindications, side effects, precautions, and drug interactions.

Pharmacological Classification

  • Therapeutic class: Antidepressant

  • Pharmacologic class: Selective serotonin reuptake inhibitor (SSRI)

  • ATC code: N06AB04

  • Chemical class: Phthalane derivative

Brand Names

  • Celexa® (United States)

  • Cipramil® (Europe, UK)

  • Other generics: Citalopram Hydrobromide 10 mg / 20 mg / 40 mg tablets or oral drops

Mechanism of Action

Citalopram works by selectively inhibiting the reuptake of serotonin (5-HT) into presynaptic neurons in the central nervous system, thereby increasing extracellular serotonin levels. This enhances serotonergic neurotransmission in key brain regions involved in mood regulation such as the prefrontal cortex, hippocampus, and limbic system.

  • No significant affinity for dopamine, norepinephrine, histamine, muscarinic, or alpha-adrenergic receptors, which contributes to its tolerability and lower side effect burden.

Indications and Clinical Uses

Approved Uses

  • Major depressive disorder (MDD)

  • Generalized anxiety disorder (GAD) (off-label in some regions)

  • Panic disorder

  • Obsessive-compulsive disorder (OCD) (off-label)

  • Premenstrual dysphoric disorder (PMDD) (off-label)

  • Postmenopausal hot flashes (off-label)

Off-label Uses

  • Post-traumatic stress disorder (PTSD)

  • Social anxiety disorder

  • Alcohol dependence (as adjunctive therapy)

  • Irritable bowel syndrome (IBS) with predominant anxiety or depression

Dosage and Administration

Adults

  • Initial dose: 20 mg once daily

  • After 1 week, dose may be increased based on clinical response

  • Max dose: 40 mg once daily in healthy adults

  • Elderly (>65 years) or hepatic impairment: maximum 20 mg/day due to QT prolongation risk

Pediatric Use

  • Not approved for use in children or adolescents in many countries due to increased risk of suicidal ideation

Elderly

  • Initiate at 10–20 mg/day; do not exceed 20 mg/day

Special Populations

  • Hepatic impairment: Reduce dose; max 20 mg/day

  • Renal impairment: Caution if CrCl <30 mL/min; no specific dose adjustment required but monitor closely

Pharmacokinetics

  • Absorption: Oral bioavailability ~80%; unaffected by food

  • Time to peak: 2–4 hours

  • Half-life: ~35 hours (once-daily dosing suitable)

  • Protein binding: ~80%

  • Metabolism: Hepatic, primarily via CYP2C19, CYP3A4, and CYP2D6

  • Elimination: Renal and fecal routes (as metabolites)

Contraindications

  • Known hypersensitivity to citalopram

  • Concomitant use with monoamine oxidase inhibitors (MAOIs) or within:

    • 14 days of stopping MAOIs

    • At least 1 week before starting MAOIs

  • Concomitant use with pimozide (due to QT prolongation risk)

  • Congenital long QT syndrome

  • Uncorrected hypokalemia or hypomagnesemia

Warnings and Precautions

  • Suicidal thoughts and behaviors: Increased risk in adolescents and young adults; monitor during initiation and dose changes

  • QT interval prolongation:

    • Risk increases with doses >40 mg/day

    • Avoid in patients with existing cardiac arrhythmias, bradycardia, or hypokalemia/hypomagnesemia

  • Serotonin syndrome: Risk when combined with other serotonergic agents (e.g., triptans, tramadol, MAOIs, SSRIs, SNRIs)

  • Hyponatremia: Especially in elderly or those on diuretics (SIADH-like syndrome)

  • Seizure risk: Use caution in patients with epilepsy

  • Angle-closure glaucoma: May precipitate in predisposed individuals

  • Hepatic impairment: Dose adjustment required

  • Mania or hypomania: May precipitate in patients with bipolar disorder

  • Withdrawal syndrome: Do not discontinue abruptly — taper gradually over several weeks

Adverse Effects

Very Common (>10%)

  • Nausea

  • Dry mouth

  • Drowsiness or insomnia

  • Increased sweating

  • Fatigue

Common (1–10%)

  • Sexual dysfunction: decreased libido, delayed orgasm, erectile dysfunction

  • Headache

  • Diarrhea or constipation

  • Tremor

  • Dizziness

  • Weight changes (usually gain)

  • Yawning

  • Agitation or anxiety

Uncommon to Rare

  • Hyponatremia, seizures

  • QT prolongation, torsades de pointes

  • Mania/hypomania

  • Suicidal ideation (particularly <25 years)

  • Serotonin syndrome

  • Abnormal liver function tests

  • Galactorrhea or gynecomastia

Drug Interactions

Increased Risk of Serotonin Syndrome

  • SSRIs, SNRIs, MAOIs

  • Tramadol, linezolid, lithium, St John’s Wort

  • Dextromethorphan, triptans

QT-Prolonging Drugs (Avoid)

  • Pimozide, haloperidol, amiodarone, quinidine, sotalol, macrolide antibiotics

CYP Interactions

  • CYP2C19 inhibitors (e.g., omeprazole, fluconazole): ↑ citalopram levels — limit dose to 20 mg/day

  • CYP inducers (e.g., carbamazepine, rifampin): ↓ effectiveness

  • CYP2D6 inhibitors (e.g., fluoxetine, paroxetine): May increase plasma levels

Other notable interactions

  • NSAIDs, aspirin, anticoagulants: ↑ risk of GI bleeding

  • Alcohol: May potentiate sedation, though no direct interaction

Pregnancy and Lactation

Pregnancy

  • Category C (U.S.) – Risk of persistent pulmonary hypertension of the newborn (PPHN) and neonatal withdrawal

  • Use only if clearly needed; benefits must outweigh potential risks

  • Avoid use during third trimester unless essential

Lactation

  • Excreted into breast milk in small amounts

  • Generally considered compatible with breastfeeding

  • Monitor infants for irritability, poor feeding, or drowsiness

Withdrawal and Discontinuation

Discontinuation must be gradual (over 2–4 weeks) to avoid withdrawal effects:

  • Flu-like symptoms, insomnia, dizziness, irritability, sensory disturbances

  • Symptoms are usually self-limiting and resolve within days to weeks

Monitoring Parameters

  • Mental health assessment at baseline and during therapy

  • Suicidality monitoring especially in the first 2 months

  • Electrolytes (potassium, magnesium) in high-risk patients

  • ECG in patients with cardiac disease or when on interacting QT-prolonging drugs

  • Liver function in hepatic impairment

  • Monitor for sexual dysfunction, weight gain, and treatment response

Patient Counseling Points

  • Take once daily, with or without food

  • May take 1–4 weeks for therapeutic effects; continue regularly

  • Do not stop abruptly without medical advice

  • Report any signs of worsening depression, suicidal ideation, or mania

  • Inform doctor before using OTC medications or herbal supplements

  • Avoid alcohol or sedating activities until individual response is known

  • Report symptoms of palpitations, dizziness, or fainting

  • Use reliable contraception if of childbearing potential

Alternatives

Other SSRIs

  • Sertraline

  • Fluoxetine

  • Escitalopram (S-enantiomer of citalopram; more selective)

  • Paroxetine

SNRIs

  • Venlafaxine, Duloxetine (in case of non-response to SSRIs)

Other Antidepressants

  • Mirtazapine

  • Bupropion

  • Tricyclic antidepressants (TCAs): reserved for resistant cases

  • MAOIs: reserved for highly resistant depression with specialist input




on
Labels:

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)