Mometasone Furoate

Corticosteroid Glucocorticoid

Dosage & Administration Guidelines

Species Route Dose Frequency Duration & Clinical Notes
Dog Oral 0.015-0.03 mg/kg q24h Duration: Varies; often tapered over 2-4 weeks
Notes: Use lowest effective dose; taper gradually to avoid adrenal suppression.
Dog Topical (cream/ointment) Thin film applied to affected area q12-24h Duration: Until resolution (max 2 weeks)
Notes: Avoid on broken skin; use with Elizabethan collar to prevent licking.
Cat Oral 0.015-0.03 mg/kg q24h Duration: Varies; often tapered over 2-4 weeks
Notes: Use with caution; cats may be more sensitive to corticosteroid side effects.
Cat Topical (cream/ointment) Thin film applied to affected area q12-24h Duration: Until resolution (max 2 weeks)
Notes: Avoid on broken skin; use with Elizabethan collar to prevent licking.
Horse Inhalation (via nebulizer) 200-400 mcg q12-24h Duration: Chronic management; adjust based on response
Notes: Use with equine aerosol chamber; monitor for respiratory improvement.
Horse Topical (cream/ointment) Thin film applied to affected area q12-24h Duration: Until resolution (max 2 weeks)
Notes: Avoid on broken skin; use with fly protection.

Clinical Indications & Species Uses

General Indications
  • Anti-inflammatory and immunosuppressive therapy for various inflammatory and allergic conditions
Dog (Canine)
  • Inflammatory and pruritic dermatoses (e.g., atopic dermatitis, allergic dermatitis)
  • Adjunct therapy for inflammatory conditions (e.g., arthritis, inflammatory bowel disease)
Cat (Feline)
  • Inflammatory and pruritic dermatoses (e.g., miliary dermatitis, eosinophilic granuloma complex)
  • Adjunct therapy for inflammatory conditions
Horse (Equine)
  • Inflammatory and allergic respiratory disease (e.g., recurrent airway obstruction, inflammatory airway disease) - via inhalation
  • Topical treatment of dermatological conditions

Pharmacology & Mechanism of Action

Drug Class: Corticosteroid | Pharmacological Group: Glucocorticoid

Mechanism of Action: Mometasone furoate is a synthetic glucocorticoid with potent anti-inflammatory, antipruritic, and immunosuppressive properties. It binds to the glucocorticoid receptor, leading to translocation into the nucleus and modulation of gene transcription. It upregulates anti-inflammatory genes (e.g., lipocortin-1) and downregulates pro-inflammatory cytokines (e.g., IL-1, IL-2, IL-6, TNF-alpha), thereby reducing inflammation and immune responses. It also inhibits phospholipase A2, reducing prostaglandin and leukotriene synthesis.

Pharmacodynamics: Mometasone furoate has high topical potency and relatively low systemic bioavailability when applied topically. It exhibits vasoconstrictive effects, reduces edema, and suppresses cellular and humoral immune responses. Its anti-inflammatory potency is greater than that of dexamethasone and betamethasone. In veterinary medicine, it is used for its anti-inflammatory and antipruritic effects in dermatological conditions.

⚡ Pharmacokinetics Summary

Absorption: When administered orally, mometasone furoate is well absorbed from the gastrointestinal tract. After topical application, absorption through intact skin is minimal but can be enhanced by inflammation or occlusion. In dogs, oral bioavailability is approximately 70%.
Distribution: Mometasone furoate is highly lipophilic and distributes widely into tissues. It crosses the placenta and is excreted in milk. It is extensively bound to plasma proteins, primarily albumin and corticosteroid-binding globulin.
Metabolism: Mometasone furoate is metabolized in the liver via cytochrome P450 enzymes, primarily CYP3A4, to inactive metabolites. It undergoes extensive first-pass metabolism after oral administration.
Excretion: Metabolites are excreted primarily in the feces (via bile) and to a lesser extent in urine. The elimination half-life is relatively short, but the duration of action is prolonged due to receptor binding.
Half-Life: Dog: ~2-3 hours (oral); Horse: ~1-2 hours (IV); Cat: ~1-2 hours (oral)
Bioavailability: Oral: ~70% in dogs; Topical: minimal systemic absorption (<5% in healthy skin)
Protein Binding: Approximately 85-90% bound to plasma proteins.

Available Formulations & Strengths

Oral Tablet 0.5 mg, 1 mg (PO)
Topical Cream 0.1% (Topical)
Topical Ointment 0.1% (Topical)
Inhalation Aerosol 200 mcg/actuation (Inhalation)

Contraindications & Clinical Warnings

Contraindications:
  • Hypersensitivity to mometasone furoate or other corticosteroids
  • Systemic fungal infections
  • Viral infections without appropriate antiviral therapy
  • Pregnancy (especially first trimester) unless benefits outweigh risks
  • Lactating animals (especially food animals) due to potential excretion in milk
  • Concurrent use of live vaccines (immunosuppression may impair immune response)
Warnings & Clinical Precautions:
  • Use with caution in animals with diabetes mellitus, renal disease, cardiac disease, hypertension, or osteoporosis.
  • Prolonged use may cause adrenal suppression; taper dose gradually.
  • In food animals, extra-label use is prohibited; withdrawal times must be observed.
  • Topical use on large areas or broken skin may lead to systemic absorption.
  • In horses, inhalation use may cause coughing or bronchospasm; monitor closely.
  • Avoid use in pregnant animals unless clearly necessary.
  • Do not use in animals with active infections unless appropriate antimicrobial therapy is administered.

Adverse Effects & Reactions

Common:

  • Increased thirst and urination
  • Increased appetite
  • Panting (in dogs)
  • Lethargy
  • Gastrointestinal upset (vomiting, diarrhea)

Serious / Severe:

  • Adrenal suppression
  • Iatrogenic Cushing's syndrome
  • Diabetes mellitus (with prolonged use)
  • Gastrointestinal ulceration
  • Pancreatitis
  • Immunosuppression leading to opportunistic infections
  • Growth retardation in young animals

Rare:

  • Hepatopathy
  • Behavioral changes
  • Seizures (in predisposed animals)
  • Allergic reactions (urticaria, angioedema)

Key Drug Interactions

Interacting Drug / Class Clinical Effect & Mechanism Severity
NSAIDs (e.g., carprofen, meloxicam) Increased risk of gastrointestinal ulceration and bleeding. High
Furosemide or other diuretics Enhanced potassium depletion and risk of hypokalemia. Moderate
Insulin or oral hypoglycemic agents May increase blood glucose; dosage adjustments may be needed. Moderate
Phenobarbital or other CYP3A4 inducers May increase metabolism of mometasone, reducing efficacy. Moderate
Ketoconazole or other CYP3A4 inhibitors May increase mometasone levels, increasing risk of adverse effects. Moderate
Live vaccines Immunosuppression may impair vaccine efficacy and increase risk of infection. High

Overdose & Toxicity Management

Signs of Toxicity:

  • Hyperglycemia
  • Glycosuria
  • Electrolyte imbalances (hypokalemia, hypernatremia)
  • Hypertension
  • Gastrointestinal ulceration
  • Behavioral changes
  • Adrenal suppression
  • Cushing's syndrome (with chronic overdose)

Emergency Treatment Protocol: Treatment is symptomatic and supportive. Induce vomiting if recent oral ingestion and animal is not showing severe signs. Administer activated charcoal to reduce absorption. Monitor electrolytes, blood glucose, and blood pressure. Provide supportive care with fluids and electrolytes. In severe cases, consider administration of trilostane or mitotane to manage hypercortisolism. Taper corticosteroids gradually to avoid withdrawal symptoms.

Food Animal Withdrawal Times

Mometasone furoate is not approved for use in food animals. Extra-label use in food animals is prohibited under AMDUCA due to lack of established withdrawal times. Do not use in animals intended for food.

Storage, Handling & Regulatory Information

Storage Temperature: Store at controlled room temperature 20-25°C (68-77°F), excursions permitted between 15-30°C (59-86°F).

Light Sensitivity: Light-sensitive — protect from direct exposure.

Handling & Special Conditions: Protect from light and moisture. Keep container tightly closed. Do not freeze.

Dispensing Status: Prescription Required (Rx Only)

Approval Status: Approved for human use (topical, nasal, inhalation). In veterinary medicine, there are no FDA-approved products containing mometasone furoate for animals; however, it may be used extra-label.

Extra-Label (Off-Label) Use: Extra-label use in animals is permitted under AMDUCA only by or on the order of a licensed veterinarian within a valid veterinarian-client-patient relationship. However, extra-label use in food animals is prohibited if it results in violative residues. Mometasone furoate is not approved for food animals; therefore, its use in food animals is not permitted.

Clinical Pearls & Practice Notes

💡 Clinical Insights: Mometasone furoate is a potent corticosteroid used primarily for its anti-inflammatory and antipruritic effects in veterinary dermatology. It is available as oral tablets, topical creams/ointments, and inhalation aerosols. In dogs and cats, it is used for allergic and inflammatory skin conditions. In horses, inhalation therapy is beneficial for managing inflammatory airway disease. Due to its potency, it is crucial to use the lowest effective dose for the shortest duration possible to minimize adverse effects. Gradual tapering is essential to avoid adrenal crisis. Monitoring for signs of hypercortisolism (polyuria, polydipsia, polyphagia) is recommended during therapy. Avoid use in animals with systemic infections unless appropriate antimicrobial coverage is provided. In food animals, its use is contraindicated due to lack of withdrawal data. Always follow label directions and consult a veterinarian for specific dosing and management.

References & Literature

  • 📚 Plumb's Veterinary Drug Handbook
  • 📚 Papich Veterinary Pharmacology and Therapeutics
  • 📚 Compendium of Veterinary Products (CVP)