Vetdrugs 2.0Zafirlukast is a cysteinyl leukotriene-receptor antagonist investigated for veterinary inflammatory disease. Clinical study in canine atopic dermatitis found sustained useful responses in only a small minority of dogs. Its potential role is therefore a narrowly qualified adjunctive application, with substantially less clinical support than established treatments for that condition.
Group
Leukotriene receptor antagonist
Mechanism of Action
Zafirlukast competitively antagonizes CysLT1 receptors and reduces signaling from cysteinyl leukotrienes such as LTD4. These mediators can promote vascular permeability, inflammatory-cell responses, mucus secretion and smooth-muscle contraction. Receptor blockade reduces susceptible leukotriene-mediated responses, but the clinical effect depends on the contribution of this pathway to the disease being treated.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Investigational atopic dermatitis regimen | Reference only | PO | Every 12 h | Up to 14 days; Trial fixed amounts every 12 hours: 34.1 kg, 30 mg. Initial 14 days on an empty stomach. The printed categories leave a gap between 22.3 and 22.7 kg; no invented band is supplied. |
| Alternative atopic dermatitis adjunct | 20 mg/animal | PO | Every 12 h | Empirical total amount with only moderate reported success; alternative to the study’s size-based regimen. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Feline asthma adjunct | 1–2 mg/kg | PO | Every 12–24 h | Limited anecdotal efficacy; not for acute bronchospasm. |
| Fixed feline asthma adjunct | 5 mg/animal | PO | Every 12 h | Alternative empirical course; not a rescue bronchodilator. |
| Mild inflammatory bowel disease adjunct | 0.15–0.2 mg/kg | PO | Every 24 h | Empirical adjunct. A reported combined case used zafirlukast 3 months, famotidine 4 weeks and sucralfate 2 weeks with a low-allergen diet; case response does not establish universal efficacy. |
| Feline asthma adjunct | 1–2 mg/kg | PO | Every 12 h | Separate explicitly oral anecdotal regimen; evidence remains limited and benefit has often been disappointing. |
Indications
- Investigational adjunctive management of pruritus associated with canine atopic dermatitis, with useful sustained improvement reported in only a small minority of dogs in a controlled study.
Contraindications
- Hypersensitivity
Interactions
- Hepatic enzyme inhibition can alter exposure to interacting medicines.
- Aspirin may raise zafirlukast concentrations.
- Erythromycin or theophylline may reduce exposure.
- Warfarin anticoagulation can be increased; follow prothrombin time.
Adverse effects
- Vomiting
- Possible hepatic adverse effects
Toxicity
Veterinary toxic thresholds are not established; assess clinical signs, liver function and interacting drugs after excess exposure.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Accolate tablets 20 mg Human tablet used in the canine trial. No verified equal-dose physical divisions encoded. | Tablet | 20 mg / tablet | PO |
| Accolate tablets 10 mg | Tablet | 10 mg / tablet | PO |
Monitoring and Administration
A trial found sustained substantial pruritus reduction in 2 of 18 completing dogs. Do not present the drug as a reliable primary treatment.
Trial administration was on an empty stomach, 1 hour before or 2 hours after food, for an initial 14 days; responders were retested for 30 days.
Do not use to treat an acute asthma attack. Hepatic impairment may reduce clearance; assess benefit and liver-related adverse effects during treatment.
Give on an empty stomach. Store protected from light and moisture in the product’s original container.
A 0.5–1 mg/kg every 12–24 hours alternative was listed without an administration route. Oral use is plausible but not established for that line; no route-specific calculation is enabled.