Escitalopram

BRAND NAMES:

Lexapro is in oral dosage form as a tablet. This is available in strengths of 5 mg, 10 mg, and 20 mg.

It is also available in the form of oral solution, available in the strength of 5 mg/mL.

MECHANISM OF ACTION:

Escitalopram is the active enantiomer of citalopram, a racemic medication. In vitro and in vivo investigations have shown that escitalopram is a highly powerful and selective serotonin reuptake inhibitor that works by specifically inhibiting the serotonin membrane transporter. In addition to its high affinity for the principal bonding site, escitalopram has a 1000-fold reduced affinity for a secondary binding site on the serotonin transporter. Escitalopram has little-to-no binding affinity for a number of additional receptors, including histamine and muscarinic receptors, and minimal action at these off-targets may account for some of its side effects.

PHARMACOKINETICS:

Absorption: Peak plasma levels of escitalopram occur around 4 hours after an oral dose is administered to healthy individuals. Escitalopram is expected to be absorbed virtually completely following oral administration and is unaffected by meals.

Distribution: The estimated amount of distribution is basically 12–26 L/kg. 

Metabolism: Escitalopram is converted in the liver into S-desmethylcitalopram and s-di-de methylcitalopram. In humans, unaltered escitalopram is the most abundant component in plasma. After numerous doses of escitalopram, the average plasma concentrations of the metabolites S-DCT and S-DDCT are typically 28–31% and 5% of the parent drug concentration, respectively. In vitro investigations indicate that metabolites play no important role in escitalopram's therapeutic activities.

Excretion: Following oral administration of escitalopram, approximately 8% of the entire dose is removed in the urine as unaltered escitalopram.

PHARMACODYNAMICS:

Escitalopram is an example of the group of drugs known as selective serotonin reuptake inhibitors. By inhibiting serotonin's reuptake into the presynaptic terminal of serotonergic neurons, these substances raise the amount of serotonin in neuronal synapses. Because of its strength, it seems to have a rather early beginning of effect when compared to other SSRIs. Patients receiving concurrent therapy with other serotonergic medications or those with a higher-than-baseline risk of bleeding should use escitalopram with caution. If escitalopram is abruptly stopped, it can potentially result in a discontinuation syndrome. If stopping therapy is necessary, it should be tapered gradually.

ADMINISTRATION:

Escitalopram is typically taken once a day, with or without food. The standard first dose of the medicine is 10 mg, with the possibility of increasing after 1 week for symptom relief. When switching from another SSRI to escitalopram, it is recommended to reduce the dose for four weeks.

DOSAGE AND STRENGTHS:

Escitalopram is administered orally and is available in 2 forms: an oral solution at a concentration of 1 mg/mL and tablets in 5 mg, 10 mg, and 20 mg strengths.

DRUG INTERACTIONS:

Escitalopram oral tablet may interact with other medications, supplements, or herbs that you are taking. An interaction happens when a substance influences how a drug works. This can be dangerous or stop the medication from working correctly.

• Blood thinners—Warfarin

Non-steroidal anti-inflammatory:

• Diclofenac
• Etodolac
• Ibuprofen
• Indomethacin
• Ketorolac
• Naproxen

Migraine drugs: 

• Almotriptan
• Eletriptan
• rizatriptan

Psychiatric drugs:

• isocarboxazid
• Phenelzine

Anti-depressant drugs:

• Citalopram
• Fluoxetine
• Paroxetine
• Sertraline

Diuretics:

• Furosemide
• Hydrochlorothiazide
• Spironolactone

CONTRAINDICATIONS

Before prescribing escitalopram, a complete risk assessment should be performed, taking into account hypersensitive reactions to other drugs, particularly antidepressants and SSRIs, potential QT prolongation, and the risk of serotonin syndrome in all individuals. Notably, this medicine is not recommended for patients who have had previous hypersensitivity responses to escitalopram.

SIDE EFFECTS

• Nausea
• Diarrhea
• Constipation
• Sexual problems in males and females
• Drowsiness
• Yawning
• Shaking
• Dizziness
• Increased sweating
• Dry mouth
• Heart burn
• Runny nose
• Sneezing

OVERDOSE

There is no particular therapy for escitalopram toxicity. The symptoms of overdosing include: 
Symptoms include:

• vomiting and dizziness
• Seizures 
• Coma 
• Nausea 

TOXICITY

Since escitalopram is well dispersed into tissue after oral administration, it is unlikely to be helpful to extract the medication from plasma using forced diuresis, dialysis, or other means. A specific counteradote for escitalopram overdose does not exist. Monitoring for cardiac irregularities, changing vital signs, and administering treatment with supportive measures when necessary should be the main goals of overdose management.

STORAGE CONDITIONS

Store at 20-25°C (68°-77°F). excursions permitted to 15-30⁰C (59-86⁰F).