Allergies and itching can be a source of discomfort for our beloved furry friends. Fortunately, there is a type of antihistamine called chlorpheniramine that can help alleviate these symptoms in dogs. Similar to diphenhydramine, chlorpheniramine is a first-generation H1 antagonist. While it does cause drowsiness, it is less sedating than diphenhydramine, making it a suitable choice for relieving allergies without causing sleepiness or for situations requiring lighter sedation. Moreover, chlorpheniramine has a good safety profile when used appropriately in healthy dogs.
Before administering any medication to your dog, it is essential to consult with your veterinarian. Although chlorpheniramine is available over-the-counter, it may not be suitable for dogs with certain medical conditions or those taking specific medications. The typical dosage of chlorpheniramine for treating dogs is 4-8 mg every 8 to 12 hours, with a maximum dose of 1.1 mg per pound. Some veterinarians recommend dosing based on the dog’s weight at 0.9-1.7 mg per pound every 8 to 12 hours, but many agree on the upper limit of 1.1 mg per pound. For sedation purposes, slightly lower amounts of around 0.5 mg per pound (up to 7 mg every 8 hours) may be used. Always follow the dosage recommended by your vet.
Branded formulations of chlorpheniramine include Chlor-Trimeton and Piriton. If you are using a branded medicine, ensure that the packaging contains no active ingredients other than chlorpheniramine. In the case of sustained-release chlorpheniramine capsules, you can open them and sprinkle the contents onto your dog’s food. However, make sure your dog consumes it before the medicine dissolves. Avoid letting your dog chew on or crush the capsules.
Is It Safe?
Chlorpheniramine is generally considered safe for healthy dogs when used as directed. However, it is crucial to exercise caution when treating dogs with certain medical conditions, as it may not be suitable for them. Some conditions to be mindful of include angle-closure glaucoma, bladder neck obstruction, chronic obstructive pulmonary disease (COPD), enlarged prostate, gastric outflow obstruction, heart disease, hypertension, hyperthyroidism, and kidney or liver impairment. Since chlorpheniramine is metabolized by the liver and excreted by the kidneys, extra caution is advised when treating dogs with impaired liver or kidney function. Additionally, the drug’s half-life may be longer in these cases. In the event of an overdose, severe and dangerous side effects may occur. If an overdose is suspected, seek immediate veterinary assistance. It is important to note that if overdose-induced seizures occur, diazepam (Valium) or barbiturates should not be administered. Pregnant or nursing animals should avoid the use of chlorpheniramine.
To ensure the safe use of chlorpheniramine, it is recommended to follow these guidelines:
- Only use the medication under the guidance of a veterinarian.
- Inform your vet about any medical conditions your dog has and any other medications or supplements your dog is receiving.
- Exercise caution when using chlorpheniramine with anticoagulant drugs (e.g., warfarin) or MAOI drugs (e.g., amitraz).
- Be cautious when treating dogs with liver disease, as the drug is metabolized by the liver.
- Chlorpheniramine may interfere with the effects of anticoagulants, and the duration of antihistamine effects can be prolonged when given with MAOIs.
What Is It Used For?
Chlorpheniramine is primarily used to treat allergies and itching in dogs. Additionally, in certain cases, it may be used as an adjunctive therapy to control the increased amounts of histamine in the body when mast cell tumors are present. It is important to note that chlorpheniramine is not a treatment for mast cell tumors themselves. Furthermore, the drug is occasionally used as a sedative.
As with any medication, chlorpheniramine can cause side effects. The most common side effect is sedation. Less common side effects may include vomiting, diarrhea, changes in appetite, urine retention, and dry mouth. In the event of an overdose, severe reactions such as seizures, difficulty breathing, coma, and even death may occur. If an overdose is suspected, contact your veterinarian or the ASPCA poison control hotline at (888) 426-4435 immediately. If the medication was administered orally and your dog is alert and stable, your veterinarian may advise inducing vomiting. Activated charcoal may also be given. In cases of seizures, intravenous administration of Phenytoin is typically recommended. Always consult a veterinary professional or ASPCA poison control specialist before taking any action.
Sources: Dr. R. Rosychuk, Dr. M. Papich, Plumb’s Veterinary Drug Handbook (sixth edition)
For more information on chlorpheniramine for dogs, visit Katten TrimSalon. It is always best to consult your veterinarian for personalized advice regarding your dog’s health and well-being. Keep your furry friend healthy and happy!