Tab levocetrizin
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levocetirizine tablet pharmacology indications dosage
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Based on established pharmacological knowledge, here is a comprehensive overview of Tab. Levocetirizine:
Tab. Levocetirizine
Drug Class
- 3rd-generation antihistamine (H₁ receptor antagonist)
- R-enantiomer of cetirizine
- Non-sedating / minimally sedating
Available Strengths
| Formulation | Strength |
|---|---|
| Tablet | 2.5 mg, 5 mg |
| Oral solution | 2.5 mg/5 mL |
Mechanism of Action
Selectively and competitively antagonizes peripheral H₁ histamine receptors, reducing histamine-mediated effects (vasodilation, increased vascular permeability, pruritus, bronchoconstriction). Has virtually no anticholinergic or anti-serotonin activity.
Indications
- Allergic rhinitis (seasonal and perennial)
- Chronic idiopathic urticaria (CIU)
- Atopic dermatitis / eczema (pruritus)
- Allergic conjunctivitis
- Angioedema (adjunctive)
Dosage & Administration
| Patient Group | Dose | Frequency |
|---|---|---|
| Adults & children ≥12 yrs | 5 mg | Once daily (evening) |
| Children 6–11 yrs | 2.5 mg | Once daily (evening) |
| Children 2–5 yrs | 1.25 mg | Once daily |
| Renal impairment (CrCl 30–50 mL/min) | 2.5 mg once daily | — |
| Renal impairment (CrCl 10–30 mL/min) | 2.5 mg every other day | — |
| CrCl <10 mL/min / hemodialysis | Contraindicated | — |
- Take with or without food
- Evening dosing preferred to minimize any residual sedation
Pharmacokinetics
| Parameter | Value |
|---|---|
| Bioavailability | ~100% |
| Onset of action | ~1 hour |
| Peak plasma (Tmax) | ~0.9 hours |
| Protein binding | ~92% |
| Half-life (t½) | ~6–10 hours |
| Metabolism | Minimal hepatic (<14%) |
| Excretion | Renal (85% unchanged) |
Contraindications
- Known hypersensitivity to levocetirizine or cetirizine
- End-stage renal disease (CrCl <10 mL/min)
- Children <12 years with renal impairment
- Hereditary galactose intolerance (lactose-containing formulations)
Adverse Effects
| Common | Uncommon/Serious |
|---|---|
| Somnolence/drowsiness | Urinary retention |
| Headache | Convulsions (rare) |
| Dry mouth | Palpitations |
| Fatigue | Aggressive behavior (children) |
| Nasopharyngitis | Angioedema (paradoxical) |
Drug Interactions
- CNS depressants (alcohol, benzodiazepines, opioids): additive sedation
- Ritonavir: increases levocetirizine AUC by ~40%
- Theophylline: may slightly reduce clearance
Special Populations
- Pregnancy: Category B — limited data; use only if clearly needed
- Lactation: Excreted in breast milk; caution advised
- Elderly: No dose adjustment needed, but monitor for somnolence and urinary retention
- Hepatic impairment: No dose adjustment required (minimal hepatic metabolism)
Key Clinical Points
- Twice as potent as cetirizine (same dose = greater H₁ occupancy)
- Minimal blood-brain barrier penetration → less sedating than older antihistamines
- Does not significantly prolong QTc interval (unlike older antihistamines)
- Preferred for daytime allergy management due to low sedation profile
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