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PetDosageChart

Antihistamine (second-generation) · For Dogs · 100 lb

How much Zyrtec for a 100 lb dog?

A 100 lb dog (45.4 kg) should receive approximately 45.4 mg of Zyrtec per dose, given once daily.

This dosage information is for educational purposes only. Always consult your veterinarian before giving any medication to your pet. Dosages may vary based on your pet's health conditions, other medications, and individual factors.

Content reviewed by licensed veterinarians. Sourced from Plumb's Veterinary Drug Handbook and the Merck Veterinary Manual.

Dosage · 100 lb dog

Zyrtec dose for a 100 lb dog

Low Dose

22.7

mg

Standard

45.4

mg

Max Safe

45.4

mg

Frequency

once daily

Weight in kg

45.4 kg

Always confirm with your veterinarian before administering medication. These calculations are estimates based on published veterinary pharmacology references.

Other Weights

Zyrtec for a different size dog

FAQ · 100 lb dog

Questions about Zyrtec for a 100 lb dog

How much Zyrtec for a 100 lb dog?
A 100 lb dog should receive approximately 45.4 mg of Zyrtec (Cetirizine) per dose, given once daily. That works out to about 9 × 5 mg. Always confirm with your veterinarian before administering medication.
What is the safe dose range of Zyrtec for a 100 lb dog?
The published dose range for a 100 lb dog is roughly 22.7 mg (low) to 45.4 mg (max safe), with 45.4 mg as the typical standard dose. Frequency: once daily.
How often can I give Zyrtec to a 100 lb dog?
Zyrtec is typically given once daily. Do not exceed the recommended frequency without veterinary guidance.

Need a different weight?

Use the calculator on the main Zyrtec page for any exact weight, or read the full dosage chart and safety information.

Full Zyrtec dosage guide →

Sources · 09

Sources & references

The dosage information on this page is compiled from the following veterinary and pharmaceutical references:

  • Plumb's Veterinary Drug Handbook — the standard veterinary pharmacology reference used by veterinarians worldwide.
  • Merck Veterinary Manual — a trusted, peer-reviewed resource for veterinary professionals and pet owners.
  • DailyMed (FDA Drug Labels) — official FDA-approved drug labeling and prescribing information for Cetirizine.

Read more about our methodology and how we calculate dosages.