Caspofungin
Caspofungin is a parenteral antifungal belonging to the **echinocandin** class. It has potential for treating invasive aspergillosis or disseminated candidal infections in companion animals, though clinical experience in veterinary medicine is currently very limited. > **Clinical Pearl**: Echinocandins are often referred to as the "penicillins of antifungals" because they target the fungal cell wall rather than the cell membrane (like azoles or amphotericin B), making them highly specific to fungi with generally lower mammalian toxicity. - **Spectrum of Activity**: Effective against *Aspergillus* spp., *Candida* spp., and *Pneumocystis carinii* pneumonia. - **Resistance/Inefficacy**: Not effective against *Cryptococcus neoformans* due to the lack of target enzymes in this organism. - **Cost**: Treatment is very expensive, often reserving it as a salvage therapy for refractory infections.
Mechanism: Caspofungin acts as a **beta-glucan synthase inhibitor**. It blocks the synthesis of **beta-(1,3)-D-glucan**, an essential structural component found in the cell walls of many filamentous fungi and yeast. **Inhibition of beta-glucan synthase** → **Depletion of beta-(1,3)-D-glucan** → **Loss of cell wall structural integrity** → **Osmotic instability and fungal cell death (fungicidal activity)**.
Dosing by species
- Invasive aspergillosis or disseminated candidal infections (Investigational) · 0.8-1.6 mg/kg · IV · Not specified · Extrapolated from human pediatric studies. Highly investigational in veterinary patients.
- Invasive aspergillosis or disseminated candidal infections (Investigational) · 0.8-1.6 mg/kg in patients weighing less than 50 kg and 50-75 mg (total dose) in those weighing more than 50 kg · IV · Not specified · Extrapolated from human pediatric studies. Highly investigational in veterinary patients.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Hypersensitivity to caspofungin
- Significant hepatic impairment
Adverse effects
- Histamine-mediated signs (rash, facial swelling, pruritus)
- Anaphylaxis
- Intravenous site reactions (pain, redness, phlebitis)
- Hepatic dysfunction
Drug interactions
- Carbamazepine · Reduced caspofungin plasma levels
- Cyclosporine · Increased caspofungin plasma levels and increased risk of hepatic enzyme increases
- Dexamethasone · Reduced caspofungin plasma levels
- Phenytoin · Reduced caspofungin plasma levels
- Rifampin · Reduced caspofungin plasma levels
Monitoring
- Clinical efficacy
- Periodic liver function tests
- CBC
- Serum electrolytes
Overdose
Limited information is available for veterinary patients. - **Humans**: Dosages of 210 mg (about 3X normal) were well tolerated. - **Primates**: Monkeys receiving 5-8 mg/kg (approx. 4-6X normal) over 5 weeks developed sites of microscopic subcapsular necrosis on their livers.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.