Lexapro
Lexapro
Generic Name
Lexapro
Brand Names
for *escitalopram*, the S‑enantiomer of citalopram, and is widely prescribed as a selective serotonin reuptake inhibitor (SSRI) for depression and anxiety disorders.
Mechanism
- Selective serotonin reuptake inhibition (SSRI)
*Escitalopram* blocks the presynaptic 5‑HT transporter (SERT), increasing extracellular serotonin in the synaptic cleft.
• High affinity for SERT (K_i ≈ 0.4 nM) and low activity at other monoamine transporters, providing a favorable side‑effect profile.
• Gradual upregulation of postsynaptic 5‑HT receptors over weeks enhances mood and reduces anxiety.
Pharmacokinetics
| Parameter | Drug‑specific data |
| Absorption | Oral bioavailability ~ 99 %; peak plasma at 5–6 h. |
| Distribution | C_max ≈ 10 ng/mL (10 mg dose). ~97 % protein bound (primarily to albumin). |
| Metabolism | Hepatic; CYP2C19 is the major oxidizing enzyme (≈70 %), with minor role for CYP3A4. |
| Half‑life | 27–32 h (t½ ≈ 1 day) → once‑daily dosing. |
| Elimination | 78 % renal (mostly active metabolites), 22 % hepatic. |
| Drug–Drug Interactions | ↑ Escitalopram levels with CYP2C19 inhibitors (e.g., fluconazole). ↓ Escitalopram levels with CYP2C19 inducers (e.g., rifampin). |
Indications
- Major Depressive Disorder (MDD) in adults and adolescents ≥12 years.
- Generalized Anxiety Disorder (GAD) in adults and adolescents ≥12 years.
- Off‑label: obsessive‑compulsive disorder, social anxiety, post‑traumatic stress, and other mood‑modulating indications.
Contraindications
- Contraindications
- Hypersensitivity to *escitalopram* or any excipient.
- Concurrent use of monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuation of an MAOI.
- Warnings
- ↑ risk of serotonin syndrome when combined with serotonergic agents (e.g., tramadol, triptans).
- QTc prolongation: caution in patients with congenital long QT, heart failure, or concurrent t‑butyl‑carboline or other cardiac drugs.
- Suicidal ideation/behavior: monitor all patients aged 18–24 years and those with a history of depression.
- Bleeding risk: caution with NSAIDs, anticoagulants, and platelet‑aggregating inhibitors.
Dosing
- Adult start dose: 10 mg orally once daily.
- Titration: Increase by ≤ 5 mg every 2 weeks based on tolerability and clinical response.
- Maximum: 20 mg daily.
- Adolescent dosing (12–17 years): start 5 mg daily; titrate by 5 mg increments every 2 weeks up to 10–20 mg.
- Administration: With or without food; take in the morning if insomnia occurs.
- Missed dose: Take as soon as remembered; skip if close to next dose.
Adverse Effects
| Category | Common (≤ 10 %) | Serious (≤ 1 %) |
| GI | Nausea, dyspepsia, flatulence | Food‑anxiety, gastrointestinal bleeding |
| Central | Insomnia, somnolence, anxiety, restlessness | Suicidal ideation/attempts, severe depression, serotonin syndrome |
| Sexual | Decreased libido, anorgasmia, erectile dysfunction | Rarely, priapism |
| Respiratory | Headache, dizziness | Pseudo‑epididymal bleeding, pulmonary aspiration |
| Metabolic | Weight changes (↑ 10 % in some) | Hyponatremia (SIADH) |
| Dermatologic | Rash, pruritus | Stevens–Johnson syndrome, toxic epidermal necrolysis |
| Cardiac | Palpitations | QTc prolongation, arrhythmias |
| Bleeding | Easy bruising | Hemorrhagic events (e.g., GI or intracranial) |
| Others | Visual disturbances | Rare visual hallucinations, seizures |
Monitoring
- Baseline & periodic:
- Patient history for suicidal thoughts, prior SSRI use.
- Physical exam: pulse, BP, ECG when QTc risk.
- Lab: CBC (for bleeding), CMP, electrolytes (especially Na⁺).
- Weight & BMI: monitor for changes > 5 % per month.
- During therapy:
- Suicidality assessment every visit for the first 4–6 weeks and whenever clinically indicated.
- Serotonin syndrome screening if combined with other serotonergic drugs: observe for clonus, agitation, hyperthermia, autonomic instability.
- QTc monitoring in patients with cardiac disease or on interacting drugs.
- Drug interaction checks: Evaluate concurrent medications with CYP2C19 substrate/inhibitor profile.
Clinical Pearls
- Start low, go slow: Escitalopram’s onset is ~2–4 weeks; titrating in 5‑mg steps every 2 weeks reduces discontinuation due to side‑effects.
- Adolescent dosing: Begin at 5 mg, double only if tolerated; watch for behavioral changes and suicidality.
- Interaction pitfalls:
- CYP2C19 inhibitors (fluconazole, cimetidine) ↑ escitalopram levels → risk of serotonin syndrome.
- CYP2C19 inducers (rifampin) ↓ escitalopram exposure → reduced efficacy.
- Serotonin syndrome red flag: “triptan + SSRI + tramadol” is a textbook high‑risk combo; patients should be screened for personal history of migraine medication overuse.
- Food doesn’t matter: Dose can be taken with or without food; inconsistent timing can cause insomnia.
- QTc caution: In patients with congenital long QT, avoid concomitant medications that prolong QT (e.g., ondansetron) and monitor ECG if the dose >15 mg/day.
- Discontinuation syndrome: Abruptly stop escitalopram → headache, flu‑like symptoms, dizziness; taper by 5 mg every 2 weeks or less.
- Drug–drug synergy: Combining escitalopram with duloxetine may enhance anxiety control but also increases hyponatremia risk; monitor electrolytes.
- Weight monitoring: Over the first 8 weeks, if weight gain > 5 % of baseline, reassess counseling or consider adjunctive weight‑neutral agents.
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• *Escitalopram (Lexapro) remains one of the first‐line SSRIs due to its favorable safety profile, rapid onset, and once‑daily dosing convenience. Clinicians should stay vigilant for serotonin syndrome, QT prolongation, and suicidal ideation when prescribing, especially in younger populations.*