Home › Compound Library › Cetirizine (Zyrtec)

Cetirizine (Zyrtec)

Antihistamineoral · inferred

Second-generation antihistamine with minimal sedation. Primarily renally excreted with minimal hepatic metabolism.

Projected serum levels — 10 mg, once daily

Cetirizine (Zyrtec)
Cetirizine (Zyrtec) modeled serum levels, 10 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 2.5 5 7.5 10 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 10 mg once daily (oral).

Modeled steady state after ~1 days: peak ≈ 7.5 mg, trough ≈ 1.1 mg body load. Population-based estimate over 15 days for a 10 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Antihistamine
Route modeled
Oral
Model confidence
inferred
Half-life
8.3 h
Common dose
10 mg
Suggested maximum
20 mg/day
Reference dose range
5–20 mg (single dose)
Suggested cadence
once daily
Validated against
10 mg oral — Cmax 0.31 mg/L at 1 h

Documented interactions

  • moderate
    Carvedilol (Coreg) + Cetirizine (Zyrtec) Transporter inhibition

    Carvedilol (Coreg) inhibitor of P-gp may alter Cetirizine (Zyrtec) absorption / distribution

  • moderate
    CBD (Cannabidiol) + Cetirizine (Zyrtec) Transporter inhibition

    CBD (Cannabidiol) inhibitor of P-gp may alter Cetirizine (Zyrtec) absorption / distribution

  • moderate
    Efavirenz (Sustiva) + Cetirizine (Zyrtec) Transporter induction

    Efavirenz (Sustiva) inducer of P-gp may alter Cetirizine (Zyrtec) absorption / distribution

  • moderate
    Fisetin + Cetirizine (Zyrtec) Transporter inhibition

    Fisetin inhibitor of P-gp may alter Cetirizine (Zyrtec) absorption / distribution

  • moderate
    Ginkgo Biloba (EGb 761) + Cetirizine (Zyrtec) Transporter inhibition

    Ginkgo Biloba (EGb 761) inhibitor of P-gp may alter Cetirizine (Zyrtec) absorption / distribution

  • moderate
    Panax Ginseng (Asian Ginseng) + Cetirizine (Zyrtec) Transporter induction

    Panax Ginseng (Asian Ginseng) inducer of P-gp may alter Cetirizine (Zyrtec) absorption / distribution

Serum checks 34 modeled interaction pairings for cetirizine (zyrtec) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. The Early Treatment of the Atopic Child (ETAC) study: cetirizine in the prevention of asthma in young children Wahn U et al. · Pediatric Allergy and Immunology, 2003 DOI

    Large RCT of 817 atopic infants showed cetirizine treatment for 18 months delayed or prevented asthma onset in children sensitized to grass pollen or house dust mites.

1 published study referenced in the app, each with a plain-language summary.