Montelukast
Montelukast is a cysteinyl leukotriene receptor antagonist used empirically as an adjunct in selected feline inflammatory diseases. Benefit in feline asthma has often been disappointing; it is not an acute bronchodilator.
Group
Leukotriene receptor antagonist
Mechanism of Action
Antagonizes CysLT1 receptors involved in leukotriene-mediated inflammation and bronchoconstriction.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Investigational use | Reference only | PO | A single 40 mg/dog dose was studied in six male Labradors for pharmacokinetics. This is a study exposure, not a universal fixed dose or an efficacy-supported maintenance regimen. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Feline asthma adjunct | 0.5–1 mg/kg | PO | Every 24 h | Anecdotal veterinary regimen with limited efficacy evidence; not for acute bronchospasm. |
| Chronic upper respiratory disease adjunct | 0.25–0.5 mg/kg | PO | Every 24 h | Anecdotal veterinary regimen with limited efficacy evidence; not for acute bronchospasm. |
| Mild inflammatory bowel disease adjunct | 0.5–1 mg/kg | PO | Every 24 h | Anecdotal veterinary regimen with limited efficacy evidence; not for acute bronchospasm. |
| Heartworm-associated respiratory disease adjunct | 2 mg/animal | PO | Every 24 h | Anecdotal adjunct intended to limit lung injury when an adult worm dies; effectiveness is unproven. |
Indications
- Investigational adjunctive treatment of selected inflammatory conditions
Contraindications
- Hypersensitivity
Interactions
- Phenobarbital or rifampin may lower exposure by enzyme induction.
- A human report links concomitant prednisone to edema; significance for animals is uncertain.
Adverse effects
- Veterinary adverse-event frequency is not established
Toxicity
No validated veterinary overdose threshold is established; assess the ingested product and provide supportive management.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Singulair tablets 4 mg montelukast equivalent Montelukast equivalent supplied as sodium salt. The 4 and 5 mg presentations are chewable; review excipients. | Tablet | 4 mg / tablet | PO |
| Singulair tablets 5 mg montelukast equivalent Montelukast equivalent supplied as sodium salt. The 4 and 5 mg presentations are chewable; review excipients. | Tablet | 5 mg / tablet | PO |
| Singulair tablets 10 mg montelukast equivalent Montelukast equivalent supplied as sodium salt. The 4 and 5 mg presentations are chewable; review excipients. | Tablet | 10 mg / tablet | PO |
Monitoring and Administration
A small canine pharmacokinetic study used a single 40 mg oral dose per Labrador; it did not establish a general therapeutic dose or treatment efficacy.
Do not use as a replacement for emergency bronchodilation or established control therapy for airway disease.
Assess benefit explicitly if used in an investigational plan and discontinue ineffective treatment.
May be administered with or without food. Store at room temperature protected from moisture and light; assess response to each empirical indication. Equine airway-obstruction research did not establish benefit.