Cequa
Cequa
Generic Name
Cequa
Mechanism
- Selective H1‑receptor antagonist: Cetirizine binds to peripheral and central H1 histamine receptors, competitively inhibiting histamine release from mast cells and basophils.
- Anti‑inflammatory effect: Reduces eosinophil infiltration and cytokine release (e.g., IL‑4, IL‑5), thereby dampening the late‑phase allergic response.
- Negligible cholinergic and sodium‑channel blockade: Results in low sedative profile compared with first‑generation antihistamines.
Pharmacokinetics
| Parameter | Value |
| Absorption | Oral bioavailability ≈ 77 %; peak plasma concentration (Tmax) ≈ 1 h (chewable tablet). |
| Distribution | Plasma protein binding ~ 35 %; crosses the blood‑brain barrier minimally. |
| Metabolism | Excreted unchanged via kidneys (≈ 64 %); minor hepatic metabolism via CYP3A4 and CYP2D6. |
| Elimination | Terminal half‑life ≈ 7 h in adults; 15–25 h in elderly (reduced clearance). |
| Special Populations | < 10 % reduction in renal clearance per 10 mL/min GFR drop. Adjust dose in severe renal impairment (CrCl < 30 mL/min). |
Indications
- Seasonal allergic rhinitis (SARS) in adults > 12 yrs and children 6–11 yrs (5 mg chewable).
- Chronic spontaneous urticaria (CSU) and angioedema in adults and adolescents.
- Other allergic skin conditions: pruritus from dermatitis, insect bites, or food allergy (off‑label but common practice).
Contraindications
- Contraindications
- Hypersensitivity to cetirizine, diphenhydramine, or any formulation excipient.
- Warnings
- Renal impairment: Dose reduction to 5 mg daily if CrCl ≤ 30 mL/min. Avoid > 10 mg daily.
- CNS depression: Avoid concomitant use of alcohol or benzodiazepines; caution in elderly or those on other CNS depressants.
- Pregnancy/Breastfeeding: Category B; use only if benefits outweigh risks; safe during lactation but monitor infant for drowsiness.
- Hepatic disease: No dose adjustment required, but consider monitoring liver enzymes if hepatic impairment is severe.
Dosing
| Population | Dose | Frequency | Notes |
| Adults > 12 yrs | 10 mg chewable tablet | Once daily | May be taken with or without food. |
| Children 6–11 yrs | 5 mg chewable tablet | Once daily | Use 5 mg formulation. |
| Pediatric 10 mg. | |||
| Elderly | 10 mg daily | Once daily | Monitor for sedation. |
• Onset: 1–2 h; peak effect 3–6 h.
• Chewable tablets provide rapid bioavailability and improved compliance in children.
Adverse Effects
| Category | Adverse Effects |
| Common (≥ 1 %) | Dry mouth, headache, nausea, drowsiness (rare), dizziness, mild constipation. |
| Less common (0.1–1 %) | Fatigue, insomnia, abdominal pain, blurred vision, rash, increased urination. |
| Serious (≤ 0.1 %) | Hypersensitivity reactions (urticaria, angioedema); anaphylaxis; significant CNS depression (especially with alcohol); rare hepatotoxicity (elevated ALT/AST). |
| Drug interactions |
• CYP3A4 inhibitors/inducers have minimal effect. • Alcohol or other CNS depressants may potentiate sedation. • Antacids can modestly reduce absorption if given simultaneously. |
Monitoring
- Renal function (CrCl/BUN‑Creatinine) in patients > 65 yrs or with chronic kidney disease; adjust dose < 30 mL/min.
- Hepatic enzymes in patients with pre‑existing liver disease or evidence of hepatic dysfunction.
- CNS effect: Monitor for excessive sedation or dizziness, particularly when initiating therapy or increasing dose.
- Efficacy: Symptom score improvement (e.g., Total Nasal Symptom Score) at 2–4 weeks.
Clinical Pearls
- Chewable Advantage: The chewable format eliminates swallowing difficulties and improves pediatric adherence.
- Non‑Sedating Profile: Unlike first‑gen antihistamines, Cequa rarely causes significant drowsiness; still advise patients to avoid alcohol or driving until they know the effect.
- Renal Dosing: Cequa’s kidney clearance necessitates dose reduction in severe CKD; do *not* double the dose if symptoms persist.
- Combo Therapy: For refractory seasonal allergic rhinitis, combine with intranasal corticosteroids (e.g., fluticasone) for superior control.
- Onset vs. On‑Demand: For acute allergic flare‑ups, a single 10 mg dose can provide rapid relief; for chronic conditions, maintain once‑daily dosing for sustained benefit.
- Pediatric Use: Children 6–11 yrs benefit from the 5 mg chewable; note that no evidence supports use < 6 yrs, so alternatives should be considered.
- Drug Interaction Checklist: Alcohol, benzodiazepines, opioids ⇒ increased sedation. Antacids ⇒ minimal but consider staggering dosing times.
- Pregnancy & Lactation: While Category B, monitor infants for excessive sleepiness; discontinue if significant sedation occurs.
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• Key takeaways: Cequa (cetirizine) is a first‑choice second‑generation antihistamine for allergic rhinitis and chronic urticaria—offering rapid relief with a favorable safety profile. Proper dosing in renal impairment, awareness of sedation interactions, and the convenience of chewable tablets make it a staple in allergy pharmacotherapy.