caspofungin

Brand: Cancidas

Prototype Drug
Drug Class: echinocandin antifungal
Drug Family: antifungal
Subclass: first-in-class echinocandin
Organ Systems: infectious-disease

Mechanism of Action

Inhibits 1,3-beta-D-glucan synthase, blocking synthesis of beta-glucan — a critical component of the fungal cell wall absent in mammalian cells; fungicidal against Candida, fungistatic against Aspergillus; mammalian selectivity explains excellent tolerability.

fungal 1,3-beta-D-glucan synthase

Indications

  • invasive candidiasis/candidemia (first-line)
  • esophageal candidiasis
  • invasive aspergillosis (salvage therapy)
  • empiric antifungal therapy in febrile neutropenia

Contraindications

  • echinocandin hypersensitivity

Adverse Effects

Common

  • fever
  • nausea
  • elevated liver enzymes
  • phlebitis

Serious

  • hepatotoxicity
  • anaphylaxis (rare)
  • histamine-mediated infusion reactions (facial flushing, rash)

Pharmacokinetics (ADME)

Absorption IV only (poor oral bioavailability)
Distribution widely distributed; highly protein-bound
Metabolism spontaneous chemical degradation and N-acetylation (not CYP-mediated primarily)
Excretion fecal (41%) and urinary (35%)
Half-life 9–11 hours
Onset immediate (IV)
Peak end of infusion
Duration 24 hours
Protein Binding 97%
Vd moderate

Drug Interactions

Drug / Agent Mechanism Severity
cyclosporine increases caspofungin AUC ~35%; increased hepatotoxicity risk; use with caution and monitor LFTs moderate
rifampin induction increases caspofungin metabolism; increase maintenance dose to 70 mg daily major
tacrolimus caspofungin reduces tacrolimus trough levels ~20%; monitor TDM moderate

Nursing Considerations

  1. Administer IV over 1 hour; incompatible with dextrose-containing solutions — use only 0.9% NaCl or Ringer's lactate as diluent.
  2. Loading dose 70 mg on day 1, then 50 mg daily (increase to 70 mg if rifampin or other enzyme inducers are co-administered).
  3. Monitor LFTs weekly; hepatotoxicity is the primary concern with extended therapy.
  4. Echinocandins are generally well-tolerated with minimal drug interactions compared to azoles — a major advantage in polypharmacy patients.

Clinical Pearls

  • Echinocandins target the fungal cell wall's beta-glucan synthase — a structure absent in mammalian cells — providing exceptional selective toxicity and a very favorable adverse effect profile.
  • Caspofungin is fungicidal against Candida but only fungistatic against Aspergillus, partly explaining why azoles (which are fungicidal against Aspergillus) are preferred for invasive aspergillosis treatment.

Safety Profile

Pregnancy use-with-caution
Lactation use-with-caution
Renal Adjustment Not required
Hepatic Adjustment Required
TDM Not required