Chlorpheniramine
Also known as: Chlor-Trimetron, Chlo-Amine, Aller-Chlor, Allergy, Allergy Relief, Chlor-Trimeton Allergy, Efidac 24, QDALL AR, ED-CHLOR-TAN, Pediox-S, Piriton
### Information for Pet Owners * **Expected Effects:** This medication is commonly used to treat allergies and itching. It may cause your pet to become drowsy or sleepy. * **Cats:** While dogs usually get sleepy, cats may occasionally experience the opposite effect and become hyperactive or excited. * **Administration:** If you are using a sustained-release (long-acting) product, **do not crush the pill or allow your pet to chew it**. The contents of sustained-release capsules may be sprinkled on food, but must be eaten immediately before they dissolve. * **Human Products:** Chlorpheniramine is an FDA-approved human medication often found over-the-counter. Only use the exact product and dose recommended by your veterinarian, as many human cold/allergy products contain additional ingredients (like decongestants or pain relievers) that can be highly toxic to pets.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- General antihistamine use
- General antihistamine use
- General antihistamine use
- Pruritus
- Pruritus
- Mild sedative
- General antihistamine use
- General use / Feather damaging behavior
- Adjunctive treatment of chemotherapy of mast cell tumors
- General antihistamine use
- General antihistamine use
- Trial for pruritus in atopic dogs
- Pruritus
- Mild sedative
How it is given
Possible side effects
- CNS depression (lethargy, somnolence, sedation)
- GI effects (diarrhea, vomiting, anorexia)
- Anticholinergic effects (dry mouth, urinary retention)
- Paradoxical excitement (especially in cats)
- Decreased performance in working dogs due to sedation
Cautions & contraindications
- Hypersensitivity to chlorpheniramine or other alkylamine antihistamines
- ### Warnings and Precautions * **Anticholinergic Effects:** Use with caution in patients with **angle closure glaucoma**, **prostatic hypertrophy**, **pyloroduodenal or bladder neck obstruction**, and **COPD** (if mucosal secretions are a problem). * **Systemic Disease:** Use cautiously in patients with **hyperthyroidism**, **cardiovascular disease**, or **hypertension**. * **Working Dogs:** Sedative effects may adversely affect the performance of working dogs. * **Laboratory Testing:** Antihistamines can decrease the wheal and flare response to antigen skin testing. It is generally recommended to discontinue antihistamines at least 4 days prior to intradermal allergy testing. * **Nursing/Pregnancy:** FDA Category B in humans. It is unknown if it is excreted in milk; use with caution in nursing dams.
Drug interactions
- Anticoagulants (heparin, warfarin): Antihistamines may partially counteract the anticoagulation effects of heparin or warfarin.
- MAO Inhibitors (amitraz, selegiline): May prolong and exacerbate the anticholinergic effects of the antihistamine.
- CNS Depressants: Increased sedation and CNS depression can occur when used concurrently.
- CNS Depressants (e.g., opioids, sedatives, barbiturates): Additive CNS depression and sedation
- Anticholinergic drugs: Additive anticholinergic effects (dry mouth, tachycardia, urinary retention)
Frequently asked questions
What is Chlorpheniramine used for in pets?
### Information for Pet Owners * **Expected Effects:** This medication is commonly used to treat allergies and itching. It may cause your pet to become drowsy or sleepy. * **Cats:** While dogs usually get sleepy, cats may occasionally experience the opposite effect and become hyperactive or excited. * **Administration:** If you are using a sustained-release (long-acting) product, **do not crush the pill or allow your pet to chew it**. The contents of sustained-release capsules may be sprinkled on food, but must be eaten immediately before they dissolve. * **Human Products:** Chlorpheniramine is an FDA-approved human medication often found over-the-counter. Only use the exact product and dose recommended by your veterinarian, as many human cold/allergy products contain additional ingredients (like decongestants or pain relievers) that can be highly toxic to pets.
Is Chlorpheniramine safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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