LEVOCETIRIZINE HYDROCHLORIDE
Clinical safety rating: safe
No significant drug interactions at recommended doses Rarely may cause somnolence.
Levocetirizine is a selective peripheral histamine H1-receptor antagonist. It inhibits the effects of histamine at the H1 receptor, reducing allergic symptoms such as itching, sneezing, and rhinorrhea. It has lower affinity for central H1 receptors and anticholinergic properties compared to first-generation antihistamines.
| Metabolism | Levocetirizine undergoes minimal hepatic metabolism; approximately 14% is metabolized by cytochrome P450 (CYP) isoenzymes, primarily CYP3A4. The remainder is excreted unchanged in urine. |
| Excretion | Approximately 85% renal excretion as unchanged drug via glomerular filtration and tubular secretion, 12.9% fecal excretion, <1% biliary. |
| Half-life | Terminal elimination half-life: 7–8 hours in healthy adults; prolonged to 20–24 hours in renal impairment (CrCl <40 mL/min); clinically, stable levels require 2–3 days. |
| Protein binding | 91–92%, primarily to albumin; minimal binding to alpha-1-acid glycoprotein. |
| Volume of Distribution | 0.4–0.5 L/kg; indicates distribution into total body water and some tissues, but low CNS penetration. |
| Bioavailability | Oral: 100% (well absorbed, no first-pass metabolism); food delays Tmax but not extent. |
| Onset of Action | Oral: 1 hour for histamine-induced wheal/flare suppression; maximal effect at 4–6 hours. |
| Duration of Action | Suppression of histamine-induced wheal/flare persists >24 hours; clinical symptom relief lasts 24 hours with once-daily dosing. |
| Molecular Weight | 388.89 Da |
| Action Class | Second-generation antihistamine (piperazine derivative) |
Oral, 5 mg once daily in the evening.
| Dosage form | SOLUTION |
| Renal impairment | GFR 50-79 mL/min: 2.5 mg once daily. GFR 30-49 mL/min: 2.5 mg every other day. GFR <30 mL/min or ESRD: contraindicated. |
| Liver impairment | Child-Pugh A and B: 2.5 mg once daily. Child-Pugh C: 2.5 mg every other day. |
| Pediatric use | 6-11 years: 2.5 mg once daily. 12 years and older: 5 mg once daily. Children <6 years: not recommended. |
| Geriatric use | 2.5 mg once daily; monitor renal function. |
| 1st trimester | Limited human data; animal studies show no teratogenicity at clinically relevant doses. Avoid unless clearly needed. |
| 2nd trimester | Limited human data; no known risk of teratogenicity. Use only if potential benefit justifies risk. |
| 3rd trimester | Limited human data; potential for neonatal adverse effects (e.g., irritability) if used near term. Use only if clearly needed. |
Clinical note
No significant drug interactions at recommended doses Rarely may cause somnolence.
| FDA category | Animal |
| Placental transfer | Levocetirizine crosses the placenta; extent not well quantified but expected to be moderate due to low molecular weight. |
| Breastfeeding |
■ FDA Black Box Warning
None
| Common Effects | urticaria |
| Serious Effects | Hypersensitivity reactions (angioedema, anaphylaxis), Seizures (especially in patients with renal impairment or electrolyte imbalance), Severe drowsiness/sedation (rare, but may impair driving ability), Urinary retention (particularly in patients with prostatic hypertrophy), Hepatotoxicity (elevated liver enzymes, hepatitis) |
Hypersensitivity to levocetirizine, cetirizine, or any piperazine derivativeSevere renal impairment (CrCl < 10 mL/min) requiring dialysis
| Precautions | Central nervous system depression: may cause drowsiness; patients should avoid driving or operating machinery until they know how the drug affects them., Renal impairment: dose adjustment required for patients with reduced renal function (CrCl < 50 mL/min)., Urinary retention: use with caution in patients with predisposing factors (e.g., prostatic hypertrophy, bladder neck obstruction). |
Loading safety data…
| Levocetirizine is excreted into human milk in low amounts; estimated relative infant dose <10% of maternal weight-adjusted dose. Monitor infant for drowsiness, irritability, or other antihistaminic effects. |
| Lactation Rating | L2 (Safer) |
| Teratogenic Risk | Levocetirizine hydrochloride is classified as FDA Pregnancy Category B. Animal studies have not demonstrated teratogenic effects, and no adequate well-controlled studies exist in pregnant women. However, postmarketing data do not indicate an increased risk of major birth defects or miscarriages. Caution is advised during the first trimester owing to theoretical risks, though the drug is generally considered low risk throughout pregnancy. |
| Fetal Monitoring | No specific monitoring is required beyond routine prenatal care. Observe for excessive sedation or anticholinergic effects in the mother. Fetal monitoring is not typically indicated unless other risk factors are present. |
| Fertility Effects | Animal studies have shown no impairment of fertility at doses up to 24 mg/kg (approximately 95 times the maximum recommended human daily oral dose). There are no human data on fertility effects. Unlikely to cause clinically relevant reproductive impairment. |
| Food/Dietary |
| No significant food interactions. Grapefruit juice does not affect pharmacokinetics. Alcohol may potentiate central nervous system depression. |
| Clinical Pearls | Levocetirizine is the active R-enantiomer of cetirizine, with twice the potency and a longer half-life (~8 hours). It has minimal anticholinergic effects and less sedation than first-generation antihistamines. Onset of action is within 1 hour. Dose adjustment required in renal impairment (CrCl <50 mL/min: 2.5 mg once daily; CrCl <10 mL/min or hemodialysis: contraindicated). No dose adjustment in hepatic impairment. Monitor for CNS depression when used with alcohol or other CNS depressants. |
| Patient Advice | Take once daily, with or without food, at the same time each day. · May cause drowsiness; avoid driving or operating heavy machinery until you know how the medication affects you. · Do not exceed recommended dose; overdose may cause severe drowsiness, confusion, or seizures. · Inform your doctor if you have kidney disease, as dose adjustment is needed. · Avoid alcohol and other sedatives while taking this medication. · Do not use for immediate relief of acute allergic reactions; use for chronic allergy symptoms. |