Citalopram

Uses

Citalopram is used for depressive illness and panic disorder. It is also used for substance abuse disorders and alcohol dependence. Citalopram has also been given in variety of anxiety disorders including obsessive-compulsive disorder and social phobia. It is also effective in generalized anxiety disorder, post-traumatic stress disorder, premenstrual syndrome, idiopathic Parkinson's disease and eating disorder.

Citalopram is also used to associated treatment for these conditions: Anorexia Nervosa (AN), Bulimia Nervosa, Depression, Diabetic Neuropathies, Major Depressive Disorder (MDD), Obsessive Compulsive Disorder (OCD), Panic Disorder, Post Traumatic Stress Disorder (PTSD), Premature Ejaculation, Premenstrual Dysphoric Disorder, Social Anxiety Disorder (SAD)

How Citalopram works

The mechanism of action of citalopram results from its inhibition of CNS neuronal reuptake of serotonin (5-HT) . The molecular target for citalopram is the serotonin transporter (solute carrier family 6 member 4, SLC6A4), inhibiting its serotonin reuptake in the synaptic cleft .

Citalopram binds with significantly less affinity to histamine, acetylcholine, and norepinephrine receptors than tricyclic antidepressant drugs . This drug has no or neglible affinity for 5-HT1A, 5-HT2A, dopamine D1 and D2, α1-, α2-, and_ β­ adrenergic, _histamine H1, gamma-aminobutyric acid (GABA), muscarinic, cholinergic, and benzodiazepine receptors. Antagonism of muscarinic, histaminergic, and adrenergic receptors is thought to be associated with several anticholinergic, sedative, and cardiovascular effects of other psychotropic drugs .

Dosage

Citalopram dosage

Depressive illness 20 mg daily as a single dose in the morning or evening; increased ifnecessary to maximum 60 mg daily (Elderly maximum 40 mgdaily).Panic disorder Initially 10 mg daily, increased to 20 mg after 7 days; usual dose 20-30 mg daily; maximum 60 mg daily (Elderly maximum 40 mgdaily).

Side Effects

SSRIs are less sedating and have fewer antimuscarinic and cardiotoxic effects than tricyclic antidepressants. However, side-effects may be seen, includes gastro-intestinal effects (nausea, vomiting, dyspepsia, abdominal pain, diarrhoea, constipation), anorexia with weight loss, palpitations, tachycardia, postural hypotension, cough, confusion, impaired concentration, amnesia, urinary retention, sweating, movement disorders, urticaria, anaphylaxis, arthralgia, myalgia and photosensitivity.

Toxicity

Oral (Human) LD: 56 mg/kg Intraperitoneal (Mouse) LD50: 179 mg/kg

Acute toxicity

Symptoms of toxicity include dizziness, sweating, nausea, vomiting, tremor, somnolence, and sinus tachycardia. Rarely, symptoms included amnesia, confusion, coma, convulsions, hyperventilation, cyanosis, rhabdomyolysis, and ECG changes (including QTc prolongation, nodal rhythm, ventricular arrhythmia, and extremely rare cases of cardiac torsade de pointes) may occur. Acute renal failure has been a rare occurrence .

In cases of overdose, establish and maintain the airway to ensure adequate ventilation and oxygen delivery. Due to the large volume of distribution of citalopram, forced diuresis, dialysis, hemoperfusion, and exchange transfusion are unlikely to be of benefit. Gastric evacuation by lavage and use of activated charcoal should be considered. Careful observation and cardiac and vital sign monitoring are advised, in addition to supportive care. With the large volume of distribution of citalopram, forced diuresis, dialysis, hemoperfusion, and exchange transfusion are unlikely to be of benefit .

Pregnancy

This drug is categorized as pregnancy category C. In animal reproduction studies, citalopram has been shown to have adverse effects on embryo/fetal and postnatal development, which includes teratogenic effects when given at doses higher than human therapeutic doses. There are no sufficient and well-controlled studies in pregnant women; therefore, citalopram should be used during pregnancy only in cases where the potential benefit justifies the possible risk to the fetus .

Pregnancy-Nonteratogenic Effects

Neonates exposed to celexa and other SSRIs or SNRIs, late in the third trimester, have undergone complications requiring prolonged hospitalization, respiratory support, and parenteral feeding. Complications such as these can arise immediately upon delivery .

Nursing Mothers

Citalopram is excreted in human breast milk. There have been two reports of infants demonstrating high levels of somnolence, reduced feeding, and weight loss associated with breastfeeding from a mother taking citalopram. In one specific case, the infant was reported to recover completely after the discontinuation of citalopram. In the second case, no follow-up information was available for assessment. The decision whether to continue or discontinue either nursing or celexa should consider the risks of citalopram exposure for the infant versus the benefits of celexa treatment for the mother .

Precaution

Caution should be taken in patients with epilepsy, concurrent electroconvulsive therapy, history of mania, cardiac disease, diabetes mellitus, angle-closure glaucoma, history of bleeding disorders, hepatic and renal impairment. Abrupt withdrawal of Citalopram should be avoided.

Interaction

Ketoconazole, Itraconazole or Macrolide antibiotics and Citalopram co-administration decreases the metabolism of Citalopram. Omeprazole and Citalopram co-administration might decrease the clearance of Citalopram.

Food Interaction

• Avoid alcohol.
• Avoid St. John's Wort.
• Take with or without food. The absorption is unaffected by food.

[Moderate] GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of CNS-active agents.

Use in combination may result in additive central nervous system depression and
MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol.

Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.

Citalopram Drug Interaction

Moderate: aspirin, aspirin, pregabalin, pregabalin, metoprolol, metoprolol, metoprolol, metoprolol, alprazolam, alprazolamUnknown: omega-3 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, levothyroxine, levothyroxine, cyanocobalamin, cyanocobalamin, ascorbic acid, ascorbic acid, cholecalciferol, cholecalciferol

Citalopram Disease Interaction

Major: depressionModerate: renal dysfunction, hyponatremia, liver disease, mania, platelet function, QT prolongation, seizure disorders, SIADHMinor: weight loss

Volume of Distribution

12 L/kg

Citalopram is highly lipophilic and likely widely distributed throughout the body, including the blood-brain-barrier. However, its metabolite, demethylcitalopram does not penetrate the blood-brain-barrier well .

Elimination Route

Rapidly and well absorbed from the GI tract. Peak plasma concentrations occur within 4 hours of a single orally administered dose. Bioavailability is 80% following oral administration. Food does not affect absorption .

Half Life

About 35 hours .

Clearance

The systemic clearance of citalopram is 330 mL/min, with approximately 20% renal clearance .

Elimination Route

12-23% of an oral dose of citalopram is found unchanged in the urine, while 10% of the dose is found in the faeces .

Pregnancy & Breastfeeding use

PregnancyThere are no adequate and well-controlled studies in pregnant women; therefore, Citalopram should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

LactationCitalopram is excreted in human breast milk. So, the decision whether to continue or discontinue either nursing or Citalopram therapy should take into account the risks of Citalopram exposure for the infants and the benefits of Citalopram treatment for the mother.

Contraindication

Citalopram should not be used if the patient enters a manic phase. Concomitant use in patients taking MAO inhibitor is contraindicated. Citalopram is contraindicated in patients with a hypersensitivity to this drug or any of its ingredients.

Acute Overdose

It is a very safe drug. There were no reports of fatal Citalopram overdose in clinical trials involving overdoses of up to 2000 mg.

Symptoms: Dizziness, sweating, nausea, vomiting, tremor, somnolence and sinus tachycardia. Rarely, amnesia, confusion, coma, seizures, hyperventilation, cyanosis, rhabdomyolysis and ECG changes (e.g. QT prolongation, sinus bradycardia, ventricular arrhythmias, nodal rhythm, torsade de pointes and left bundle branch block).

Management: Symptomatic and supportive treatment. Maintain and ensure adequate ventilation and oxygenation. Gastric evacuation by lavage and use of activated charcoal should be considered. Frequently monitor cardiac function and vital signs.

Interaction with other Medicine

Ketoconazole, Itraconazole or Macrolide antibiotics and Citalopram co-administration decreases the metabolism of Citalopram. Omeprazole and Citalopram co-administration might decrease the clearance of Citalopram.

Storage Condition

Store at 25° C.

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