Introduction
Quzyttir (cetirizine hydrochloride) is a second-generation antihistamine approved by the FDA in 2020 specifically for the treatment of acute urticaria (hives) and allergic reactions in adults and pediatric patients 6 months and older. It represents a novel intravenous formulation of cetirizine, providing rapid onset of action for patients who cannot take oral medications or require immediate symptom control.
Mechanism of Action
Quzyttir functions as a selective histamine H1-receptor antagonist. It competitively inhibits histamine binding at H1-receptors, preventing the physiological effects of histamine release including vasodilation, increased vascular permeability, and smooth muscle contraction. Unlike first-generation antihistamines, Quzyttir demonstrates minimal anticholinergic effects and has limited penetration across the blood-brain barrier, resulting in reduced sedative properties.
Indications
- Treatment of acute urticaria in adults and pediatric patients 6 months and older
- Management of allergic reactions in settings where oral therapy is not feasible
- Use in emergency departments for rapid relief of allergic symptoms
Dosage and Administration
Adults and pediatric patients 12 years and older: 10 mg intravenous injection over 1-2 minutes Pediatric patients 6-11 years: 5 mg or 0.09 mg/kg intravenous injection (maximum 10 mg) Pediatric patients 6 months to 5 years: 0.18 mg/kg intravenous injection (maximum 5 mg) Administration: Administer as IV push over 1-2 minutes. No dilution required. May be administered without regard to meals. Renal Impairment: For patients with creatinine clearance 11-31 mL/min, administer 5 mg IV every 24 hours. For patients with creatinine clearance ≤10 mL/min, avoid use.Pharmacokinetics
Absorption: 100% bioavailability via IV administration with immediate onset of action Distribution: Volume of distribution approximately 0.5 L/kg; protein binding 93% Metabolism: Minimal hepatic metabolism via cytochrome P450 enzymes; primarily undergoes oxidative dealkylation Elimination: Half-life approximately 8 hours; primarily excreted unchanged in urine (60%) with fecal elimination accounting for approximately 10% Time to peak effect: Within 1 hour of administrationContraindications
- Hypersensitivity to cetirizine, hydroxyzine, or any component of the formulation
- Patients with known hypersensitivity to other piperazine derivatives
Warnings and Precautions
- Sedation: May cause drowsiness; patients should exercise caution when operating machinery or performing hazardous activities
- Renal impairment: Dose adjustment required in moderate to severe renal impairment
- Geriatric patients: Increased susceptibility to adverse effects; consider renal function
- Pregnancy: Category B - use only if clearly needed
- Lactation: Cetirizine is excreted in breast milk; caution advised
- Patients with urinary retention: Use with caution in patients with predisposing factors
Drug Interactions
- CNS depressants: Enhanced sedative effects with alcohol, benzodiazepines, opioids, and other sedating medications
- Theophylline: Mild pharmacokinetic interaction observed with oral cetirizine
- Ritonavir: May increase cetirizine concentrations
- Anticholinergic drugs: Potential additive effects
Adverse Effects
Common (≥2%):- Somnolence (13%)
- Fatigue (6%)
- Dizziness (4%)
- Headache (3%)
- Nausea (2%)
- Hypersensitivity reactions including anaphylaxis
- Seizures (case reports)
- Urinary retention
- Hepatitis (rare reports)
Monitoring Parameters
- Relief of urticaria symptoms and allergic manifestations
- Signs of sedation or cognitive impairment
- Renal function in patients with pre-existing renal disease
- Signs of hypersensitivity reactions during administration
- Urinary function in predisposed patients
Patient Education
- Inform patients about potential drowsiness and advise against driving or operating machinery until effects are known
- Report any signs of allergic reaction during or after administration
- Avoid alcohol and other CNS depressants while taking Quzyttir
- Notify healthcare provider if pregnancy is suspected or planned
- Seek immediate medical attention for difficulty urinating, seizures, or severe dizziness
- Storage: Store at controlled room temperature (20-25°C)
References
1. FDA prescribing information: Quzyttir (cetirizine hydrochloride) injection 2. Bernstein JA, et al. Efficacy and safety of intravenous cetirizine for the treatment of acute urticaria: Results from a randomized, double-blind, placebo-controlled trial. Ann Allergy Asthma Immunol. 2020;124(4):356-362 3. Church MK, et al. The role of cetirizine in the changing landscape of antihistamine treatment. Clin Exp Allergy. 2021;51(1):21-28 4. Zuberbier T, et al. The EAACI/GA²LEN/EDF/WAO guideline for the definition, classification, diagnosis and management of urticaria. Allergy. 2018;73(7):1393-1414 5. Simons FER, et al. Comparative pharmacology of H1 antihistamines: Clinical relevance. Am J Med. 2002;113(Suppl 9A):38S-46S