Celexa

Action

Unclear. Thought to potentiate serotonergic activity in CNS by inhibiting neuronal uptake of serotonin.

Availability

Oral solution: 10 mg/5 ml

Tablets: 10 mg, 20 mg, 40 mg

Indications and dosages

➣ Depression

Adults: Initially, 20 mg P.O. daily; may increase to maximum recommended dosage of 40 mg/day at an interval of no less than 1 week.

Dosage adjustment

• Hepatic impairment

• CYP2C19 poor metabolizers or concurrent use of cimetidine or another CYP2C19 inhibitor

• Elderly patients

Off-label uses

• Alcoholism

• Panic disorder

• Premenstrual dysphoria

• Social phobia

Contraindications

• Hypersensitivity to drug or its components

• Concurrent use of MAO inhibitors or pimozide

Precautions

Use cautiously in:

• severe renal impairment, hepatic impairment

• bradycardia, hypokalemia, hypomagnesemia, hyponatremia, recent acute myocardial infarction, congenital long QT syndrome, or uncompensated heart failure (avoid use)

• concurrent use of drugs that prolong QTc interval (avoid use)

• concurrent use of serotonin precursors such as tryptophan (not recommended)

• concurrent use of aspirin, NSAIDs, warfarin, and other anticoagulants

• history of mania or seizure disorder

• elderly patients

• pregnant or breastfeeding patients

• children (safety not established).

Administration

• Administer drug in the morning or evening, with or without food.

☞ Don't give within 14 days of MAO inhibitor; life-threatening interactions may occur.

☞ Be aware that drug shouldn't be given at doses above 40 mg/day because of risk of QTc-interval prolongation.

☞ Gradually reduce dosage rather than abruptly stopping drug.

Adverse reactions

CNS: apathy, confusion, drowsiness, insomnia, migraine, weakness, agitation, amnesia, anxiety, dizziness, fatigue, poor concentration, tremor, paresthesia, deepening of depression, suicide attempt, neuroleptic malignant syndrome-like reactions

CV: orthostatic hypotension, tachycardia, ECG changes

Metabolic: hyponatremia

EENT: abnormal visual accommodation

GI: nausea, vomiting, diarrhea, abdominal pain, dyspepsia, flatulence, increased saliva, dry mouth, increased appetite, anorexia

GU: polyuria, amenorrhea, dysmenorrhea, ejaculatory delay, erectile dysfunction, decreased libido

Musculoskeletal: joint pain, myalgia

Respiratory: cough

Skin: rash, pruritus, diaphoresis, photosensitivity

Other: altered taste, fever, yawning, weight changes, serotonin syndromelike reactions

Interactions

Drug-drug. Aspirin, NSAIDs, warfarin, other anticoagulants: increased risk of bleeding

Anti-infectives (such as gatifloxacin, moxifloxacin), antipsychotics (such as chlorpromazine, thioridazine), Class 1A antiarrhythmics (such as procainamide, quinidine), Class III antiarrhythmics (such as amiodarone, sotalol), CYP2C19 inhibitors (such as cimetidine), methadone, pentamidine: risk of prolonged QTc interval

Carbamazepine: decreased citalopram blood level

Centrally acting drugs (such as antihistamines, opioids, sedative-hypnotics): additive CNS effects

Erythromycin, itraconazole, ketoconazole, omeprazole: increased citalopram blood level

5-hydroxytryptamine₁ receptor agonists (such as sumatriptan, zolmitriptan): increased risk of adverse reactions

Lithium: potentiation of serotonergic effects

MAO inhibitors: life-threatening reactions

Tricyclic antidepressants (TCAs): altered TCA pharmacokinetics

Drug-diagnostic tests. Serum sodium: decreased level

Drug-herbs. St. John's wort, S-adenosylmethionine (SAM-e): increased risk of serotonergic reactions, including serotonin syndrome

Drug-behaviors. Alcohol use: additive CNS depression

Sun exposure: photosensitivity

Patient monitoring

• If patient is receiving lithium concurrently, watch closely for potentiation of serotonergic effects.

• Monitor patient for signs of mania or hypomania, bleeding, serotonin syndrome-like reactions (including mental status changes, such as agitation, hallucinations, coma), autonomic instability (such as tachycardia, labile blood pressure, hyperthermia), neuromuscular aberrations (such as hyperreflexia, incoordination), GI symptoms (such as nausea, vomiting, diarrhea) or neuroleptic malignant syndrome-like reactions (fever, muscle rigidity, mental status changes, irregular pulse or blood pressure, rapid heartbeats, excessive sweating).

• Monitor ECG and electrolyte levels in patients with cardiac conditions that may lead to QT-interval prolongation. Discontinue drug in patients with persistent QTc measurements of more than 500 ms.

• Be aware that drug should be discontinued in patients with symptomatic hyponatremia (headache, difficulty concentrating, memory impairment, confusion, weakness, unsteadiness). Signs and symptoms associated with more severe or acute cases have included hallucinations, syncope, seizures, coma, respiratory arrest, and death).

• When discontinuing drug, monitor patient for dysphoria, irritability, agitation, dizziness, sensory disturbances, anxiety, confusion, headache, lethargy, emotional lability, insomnia, and hypomania.

Patient teaching

• Instruct patient to take drug with full glass of water with or without food at same time every day.

☞ Advise patient or caregiver (especially if drug is given to a child or adolescent) to immediately report suicidal thoughts or extreme depression.

• Instruct patient to move slowly when sitting up or standing, to avoid dizziness or light-headedness caused by sudden blood pressure decrease.

• Tell patient several weeks may pass before he starts to feel better.

• Instruct patient to immediately report irregular or rapid heartbeats, dizziness, fainting, palpitations, agitation, hallucinations, incoordination, nausea, vomiting, diarrhea, fever, muscle rigidity, altered mental status (including catatonic signs), excessive sweating, headache, difficulty concentrating, memory impairment, confusion, weakness, and unsteadiness.

• Tell patient about risk of bleeding associated with concomitant use of this drug and NSAIDs, aspirin, or other drugs that affect coagulation; tell patient to report bruising or other signs or symptoms of bleeding.

• Caution patient to avoid driving and other hazardous activities until drug's effects on concentration and alertness are known.

• Advise patient to avoid alcohol during therapy.

• Tell male patient he may experience inadequate filling of penile erectile tissue. Advise him to consult prescriber if he experiences adverse sexual effects.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.