Antihistamine (second-generation) · For Dogs

Claritin dosage reference for dogs (Loratadine)

This page's standard weight-based reference is 0.5 mg per kg (0.23 mg per lb), with once daily recorded as the reference frequency. Use the calculator to see the arithmetic for your dog's weight, then confirm the indication, product, and actual dose with a veterinarian.

Onset: 1-3 hours
Duration: 24 hours
Class: Antihistamine (second-generation)

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 an antihistamine (second-generation) commonly used in veterinary medicine for allergies, itching, atopic dermatitis, and mast cell tumors (adjunct). Understanding the correct dosage, administration, and potential side effects of Loratadine is critical for your dog’s safety and well-being.

A typical Loratadine dose for dogs is around 0.5 mg/kg once daily, within a usual range of 0.25-1 mg/kg. Available forms include tablet and liquid.

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 Dogs

Enter your dog’s weight below to estimate the Loratadine dose from the 0.5 mg/kg guideline. Your veterinarian may adjust it for your dog’s age, condition, and other medications, so treat the result as an educational starting point, not a prescription.

Dosage Calculator · 01

Enter your dog's weight

Quick Dosage Chart

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

Dosage Chart · 02

Claritin weight-based reference chart for dogs

Scroll sideways to see full table

Weight	Lower Reference	Standard Reference	Upper Reference	Frequency
5 lbs (2.3 kg)	0.57 mg	1.1 mg	2.3 mg	once daily
10 lbs (4.5 kg)	1.1 mg	2.3 mg	4.5 mg (5mg tablet)	once daily
15 lbs (6.8 kg)	1.7 mg	3.4 mg	6.8 mg	once daily
20 lbs (9.1 kg)	2.3 mg	4.5 mg (5mg tablet)	9.1 mg (2 × 5mg)	once daily
25 lbs (11.3 kg)	2.8 mg	5.7 mg (5mg tablet)	11.3 mg	once daily
30 lbs (13.6 kg)	3.4 mg	6.8 mg	13.6 mg	once daily
40 lbs (18.1 kg)	4.5 mg (5mg tablet)	9.1 mg (2 × 5mg)	18.1 mg	once daily
50 lbs (22.7 kg)	5.7 mg (5mg tablet)	11.3 mg	22.7 mg	once daily
60 lbs (27.2 kg)	6.8 mg	13.6 mg	27.2 mg	once daily
70 lbs (31.7 kg)	7.9 mg	15.8 mg (3 × 5mg)	31.7 mg	once daily
80 lbs (36.3 kg)	9.1 mg (2 × 5mg)	18.1 mg	36.3 mg	once daily
90 lbs (40.8 kg)	10.2 mg (2 × 5mg)	20.4 mg (4 × 5mg)	40.8 mg (8 × 5mg)	once daily
100 lbs (45.4 kg)	11.3 mg	22.7 mg	45.4 mg (9 × 5mg)	once daily
120 lbs (54.4 kg)	13.6 mg	27.2 mg	54.4 mg (11 × 5mg)	once daily
150 lbs (68 kg)	17.0 mg	34.0 mg (7 × 5mg)	68.0 mg	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 dog 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 Dog

Use plain loratadine (Claritin) only — do NOT use Claritin-D, which contains pseudoephedrine, a decongestant toxic to dogs. Can be given with or without food. Claritin causes less drowsiness than first-generation antihistamines like Benadryl.

It may interact with ketoconazole, erythromycin, cimetidine, and other CNS depressants.

Side Effects and Safety

Common side effects include mild sedation, dry mouth, and urinary retention. More serious side effects can occur, such as excessive sedation, rapid heartbeat, and hypersensitivity reaction.

Cautions · 12

When Claritin should be used with caution or avoided

Some dogs 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.

severe liver disease
known hypersensitivity

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 dog's medications and supplements.

ketoconazole

erythromycin

cimetidine

other CNS depressants

Calculator Limits · 14

When not to use this calculator

This calculator gives a general educational estimate for a healthy adult dog 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 dogs
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 dog's current, accurate weight
For combination products that contain additional active ingredients

Overdose · 15

Suspected overdose: what to do

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

Allergic symptoms worsen or do not improve
Excessive drowsiness or lethargy
Rapid heartbeat
Difficulty urinating
Vomiting or diarrhea

Frequently Asked Questions

Frequently Asked · 07

Questions about this medication

Can I give my dog Claritin?

Yes, plain Claritin (loratadine) is generally considered safe for dogs for allergy relief. However, you must never use Claritin-D, which contains pseudoephedrine — this decongestant is toxic to dogs. Always consult your veterinarian for the correct dose.

How much Claritin can I give my dog?

The typical dose is 0.5 mg per kilogram of body weight, given once daily. Small dogs (under 15 lbs) usually get half of a 5 mg tablet, medium dogs get one 5 mg tablet, and large dogs get one 10 mg tablet daily.

Is Claritin better than Benadryl for dogs?

Claritin and Benadryl work differently. Claritin (second-generation) causes less drowsiness and lasts 24 hours, requiring only once-daily dosing. Benadryl (first-generation) works faster but causes more sedation and needs to be given 2-3 times daily. Your vet can recommend which is better for your dog's situation.

How long does it take Claritin to work in dogs?

Claritin typically starts working within 1-3 hours. For best results with chronic allergies, give it consistently once daily. Some dogs may need several days of consistent dosing to see full benefit.

Use This Guide Safely · 08

What weight alone cannot tell you

The calculator performs one narrow job: it multiplies your dog'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: allergies, itching, atopic dermatitis, mast cell tumors (adjunct)
Recorded forms: tablet, liquid
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

severe liver disease; known hypersensitivity.

Recorded interactions

ketoconazole; erythromycin; cimetidine; other CNS depressants.

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

Related · 08

Related medications for dogs

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 0.5 mg per kg (0.23 mg per lb) of body weight, given once daily. The calculator multiplies that basis by your dog'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 dogs 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