Second-Generation Antihistamine (H1 Receptor Antagonist) · For Cats

Claritin dosage reference for cats (Loratadine)

This page's standard weight-based reference is 0.375 mg per kg (0.17 mg per lb), with Once daily recorded as the reference frequency. Use the calculator to see the arithmetic for your cat's weight, then confirm the indication, product, and actual dose with a veterinarian.

Onset: 1-3 hours
Duration: 24 hours
Class: Second-Generation Antihistamine (H1 Receptor Antagonist)

Weight-based calculator estimate from the references listed on this page. This page has not been independently DVM-reviewed — see our methodology .

This information is for educational purposes only. Always consult your veterinarian before giving medication to your pet. Do not use this calculator for emergencies, overdoses, pregnancy, very young animals, very old animals, pets with liver/kidney disease, or pets taking multiple medications.

Each medication page lists the references recorded for its data. The calculator math and editorial presentation are maintained by PetDosageChart; a page is independently DVM-reviewed only when a named reviewer byline appears. See our methodology and limitations.

Loratadine (often known by brand names such as Claritin) is a second-generation antihistamine (H1 receptor antagonist) commonly used in veterinary medicine for Allergic dermatitis, Environmental allergies (atopy), Itching and scratching, and Allergic rhinitis. Understanding the correct dosage, administration, and potential side effects of Loratadine is critical for your cat’s safety and well-being.

A typical Loratadine dose for cats is around 0.375 mg/kg Once daily, within a usual range of 0.25-0.5 mg/kg. Available forms include Tablet and Oral syrup.

Calculator Warning: Use this only as an educational estimate. Your veterinarian may prescribe a different dose based on your pet’s condition, age, weight, other medications, and medical history.

Loratadine Dosage Calculator for Cats

Enter your cat’s weight below to estimate the Loratadine dose from the 0.375 mg/kg guideline. Your veterinarian may adjust it for your cat’s age, condition, and other medications, so treat the result as an educational starting point, not a prescription.

Dosage Calculator · 01

Enter your cat's weight

Quick Dosage Chart

Typical Loratadine amounts for common cat weights, for quick reference:

Dosage Chart · 02

Claritin weight-based reference chart for cats

Scroll sideways to see full table

Weight	Lower Reference	Standard Reference	Upper Reference	Frequency
3 lbs (1.4 kg)	0.35 mg	0.52 mg	0.70 mg	Once daily
4 lbs (1.8 kg)	0.45 mg	0.68 mg	0.90 mg	Once daily
5 lbs (2.3 kg)	0.57 mg	0.86 mg	1.1 mg	Once daily
6 lbs (2.7 kg)	0.68 mg	1.0 mg	1.4 mg	Once daily
7 lbs (3.2 kg)	0.80 mg	1.2 mg	1.6 mg	Once daily
8 lbs (3.6 kg)	0.90 mg	1.4 mg	1.8 mg	Once daily
9 lbs (4.1 kg)	1.0 mg	1.5 mg	2.0 mg	Once daily
10 lbs (4.5 kg)	1.1 mg	1.7 mg	2.3 mg	Once daily
12 lbs (5.4 kg)	1.4 mg	2.0 mg	2.7 mg	Once daily
14 lbs (6.3 kg)	1.6 mg	2.4 mg	3.1 mg	Once daily
16 lbs (7.3 kg)	1.8 mg	2.7 mg	3.6 mg	Once daily
18 lbs (8.2 kg)	2.0 mg	3.1 mg	4.1 mg (5mg tablet)	Once daily
20 lbs (9.1 kg)	2.3 mg	3.4 mg	4.5 mg (5mg tablet)	Once daily
25 lbs (11.3 kg)	2.8 mg	4.2 mg (5mg tablet)	5.7 mg (5mg tablet)	Once daily

Parenthetical tablet amounts are arithmetic comparisons only. They do not account for scoring, release type, concentration, product labeling, or whether this medication is appropriate for an individual animal.

By Weight

Claritin reference by cat weight

Choose a common weight to open its optional reference page. Use the main medication calculator for a different exact weight.

Common-weight pages are convenience views of the same educational reference, not separate medical recommendations.

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How to Give Loratadine to Your Cat

Loratadine tablets can be cut to the appropriate dose and hidden in a pill pocket or small piece of soft treat. Because cat doses are small fractions of human tablets, precise cutting is important—a pill cutter helps. Alternatively, use the children’s liquid suspension (1 mg/mL) measured with an oral syringe for accurate dosing. The liquid can be mixed into a small amount of wet food. Loratadine can be given with or without food. Always verify the product is plain loratadine—NEVER Claritin-D.

It may interact with Ketoconazole and other azole antifungals (increased loratadine levels), Erythromycin (increased loratadine levels), Other antihistamines (additive effects), and CNS depressants (mild additive sedation).

Side Effects and Safety

Common side effects include Mild sedation (less than first-generation antihistamines), Dry mouth, Decreased appetite, and Gastrointestinal upset. More serious side effects can occur, such as Urinary retention, Rapid heart rate (tachycardia), Severe allergic reaction to the medication, and Liver dysfunction (rare).

Cautions · 12

When Claritin should be used with caution or avoided

Some cats should not take Claritin, or need a different dose and closer monitoring. Tell your veterinarian about your pet's full health history and every other medication or supplement they take before giving Claritin.

Known hypersensitivity to loratadine
Severe liver disease (loratadine is hepatically metabolized)
NEVER use Claritin-D (contains pseudoephedrine, which is toxic to cats)

Interactions · 13

Claritin drug interactions

Claritin can interact with other drugs. This list is not complete — always give your veterinarian a full list of your cat's medications and supplements.

Ketoconazole and other azole antifungals (increased loratadine levels)

Erythromycin (increased loratadine levels)

Other antihistamines (additive effects)

CNS depressants (mild additive sedation)

Calculator Limits · 14

When not to use this calculator

This calculator gives a general educational estimate for a healthy adult cat at a known weight. Do not rely on it in these situations — talk to your veterinarian instead:

In an emergency, or after accidental ingestion or a suspected overdose
For pregnant or nursing pets
For very young or very old cats
For pets with liver disease, kidney disease, or another chronic illness
For pets taking several medications at once
When you are not sure of your cat's current, accurate weight
For combination products that contain additional active ingredients

Overdose · 15

Suspected overdose: what to do

If you think your cat had too much Claritin, or swallowed any medication by accident, act right away. Do not wait for symptoms to appear.

Call your veterinarian or the nearest emergency animal hospital.
ASPCA Animal Poison Control Center: (888) 426-4435
Pet Poison Helpline: (855) 764-7661

A consultation fee may apply to the poison hotlines. Have the medication packaging ready, and note how much your pet may have taken and when. Do not try to make your pet vomit unless a veterinarian tells you to.

When to Call the Vet

If your cat experiences any of the following, contact your veterinarian or an emergency clinic immediately:

Rapid heart rate or panting
Difficulty urinating or straining in the litter box
Signs of allergic reaction: facial swelling, hives, vomiting
Extreme lethargy or disorientation
No improvement in allergy symptoms after 2 weeks of daily use

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

Can I give my cat Claritin for allergies?

Plain loratadine (Claritin) can be given to cats for allergy symptoms at a dose of 0.25-0.5 mg/kg once daily. For an average 4 kg cat, this is about 1-2 mg per day. CRITICAL WARNING: Never use Claritin-D, which contains pseudoephedrine—a decongestant that is toxic and potentially fatal to cats. Always check the label to ensure it is plain loratadine only.

Is Claritin less sedating than Benadryl for cats?

Yes, loratadine (Claritin) is a second-generation antihistamine that causes significantly less sedation than diphenhydramine (Benadryl), which is a first-generation antihistamine. This makes Claritin a better choice for cats that become overly drowsy on Benadryl or need daily allergy management without sedation. However, some cats may still experience mild drowsiness.

How do I dose Claritin for a small cat?

For small cats (3-4 kg), the dose is approximately 0.75-2 mg of loratadine per day. Since Claritin tablets come in 5 mg and 10 mg sizes, you will likely need to cut the tablet. A quarter of a 5 mg tablet (1.25 mg) is a common starting dose for an average-sized cat. The children's liquid formulation can make measuring small doses easier—but check that it does not contain xylitol or pseudoephedrine.

How long does it take for Claritin to work in cats?

Loratadine typically begins working within 1-3 hours in cats. For chronic allergies, the full benefit may take several days of consistent daily dosing to become apparent. Antihistamines are generally more effective when given preventatively before allergen exposure rather than after itching has already started.

Can I use Claritin liquid for my cat?

Yes, the children's liquid formulation of loratadine can be easier to dose for cats. Ensure the product contains ONLY loratadine as the active ingredient—no pseudoephedrine (Claritin-D) and no xylitol sweetener (toxic to some animals). The standard children's liquid is 1 mg/mL, making it relatively easy to measure small cat-appropriate doses with a syringe.

Use This Guide Safely · 08

What weight alone cannot tell you

The calculator performs one narrow job: it multiplies your cat's weight by the lower, standard, and upper mg/kg values recorded for Claritin. It cannot decide whether this drug, indication, formulation, or schedule is appropriate for an individual animal.

Context in this medication record

Commonly listed uses: Allergic dermatitis, Environmental allergies (atopy), Itching and scratching, Allergic rhinitis
Recorded forms: Tablet, Oral syrup
Reference timing: Once daily; onset 1-3 hours; duration 24 hours

Individual checks a calculator cannot perform

Confirm the diagnosis and the reason this medication is being considered.
Match the exact product, concentration, route, and whether a tablet may be split.
Account for age, pregnancy, organ function, genetics, allergies, and prior reactions.
Review every prescription, over-the-counter product, and supplement your pet takes.

Recorded cautions

Known hypersensitivity to loratadine; Severe liver disease (loratadine is hepatically metabolized); NEVER use Claritin-D (contains pseudoephedrine, which is toxic to cats).

Recorded interactions

Ketoconazole and other azole antifungals (increased loratadine levels); Erythromycin (increased loratadine levels); Other antihistamines (additive effects); CNS depressants (mild additive sedation).

These lists reproduce the structured record used by this page and may not be exhaustive. Show your veterinarian the product label and your cat's complete medication list before acting on a number.

Related · 08

Related medications for cats

Sources · 09

Sources & references

The structured medication record behind this page names the references below. The links open the publisher or official resource; they do not turn this page into a prescription for an individual animal.

Plumb's Veterinary Drug Handbook — listed in this medication's source record.
Merck Veterinary Manual — listed in this medication's source record.
DailyMed label search for Loratadine — check current product and formulation labels; some veterinary uses may be off-label.

Source names are shown at the record level; passage-level page and label citations are still being added. Read our methodology and limitations.

Transparency · 11

How this page was made

This page's structured medication record includes Plumb's Veterinary Drug Handbook among its source names. PetDosageChart applies the record's mg/kg values to the entered weight and presents the arithmetic result. A source record is not the same as an individualized prescription or an independent clinical review.

Sources cited: Plumb's Veterinary Drug Handbook
Merck Veterinary Manual
Calculator formula: Doses scale linearly from a standard basis of 0.375 mg per kg (0.17 mg per lb) of body weight, given Once daily. The calculator multiplies that basis by your cat's weight and shows an arithmetic comparison with recorded tablet sizes. That comparison does not determine whether a tablet is scored, splittable, or appropriate for your pet.
Editorial owner: Prepared and maintained by the PetDosageChart editorial team, a software-led publisher and not a veterinary practice.
DVM review status: Not independently DVM-reviewed. A named reviewer and review date appear here only after a confirmed review.

More on our methodology and editorial process — how we source, calculate, and review cats dosage data.

Safety · 10

More resources

Pet Medication Safety Hub — What's safe, what's dangerous, and emergency signs
How we calculate dosages — Our sources, math, and review process
Printable emergency checklist — One-page reference for your fridge or first aid kit