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. |
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 | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
No significant drug interactions at recommended doses Rarely may cause somnolence.
| FDA category | Animal |
| Breastfeeding | Levocetirizine is excreted into human breast milk in small amounts. The milk-to-plasma ratio (M/P) is not well established but is estimated to be low based on cetirizine data (M/P ~0.25). The estimated infant dose is <1% of the maternal weight-adjusted dose. No adverse effects in breastfed infants have been reported. Use with caution in nursing mothers, especially in premature infants or those with renal impairment. |
| Teratogenic Risk |
■ FDA Black Box Warning
None
| Common Effects | urticaria |
| Serious Effects |
["Hypersensitivity to levocetirizine or any of its components","End-stage renal disease (CrCl < 10 mL/min) or patients undergoing hemodialysis","Children under 6 months of age (safety and efficacy not established)"]
| 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 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. |