Weekly Sirolimus (Rapamycin) Dosing Guidelines for Feline HCM

Weekly Sirolimus Dosing for HCM

Sirolimus (often referred to as Rapamycin) is an immunosuppressive agent that has shown immense therapeutic potential at lower, intermittent doses for feline hypertrophic cardiomyopathy. It acts by blocking the mechanistic target of rapamycin (mTOR) signaling pathway, which is heavily involved in pathologic cell growth and hypertrophy.

Why Weekly Dosing?

Clinical veterinary trials have demonstrated that administering Sirolimus once weekly (rather than daily) is highly effective for heart remodeling control while minimizing potential side effects. The standard recommended weekly starting dose is typically 0.3 mg to 0.4 mg per kilogram of cat body weight.

The Enteric Coating Requirement

Sirolimus is highly sensitive to gastric acid. To prevent chemical breakdown in the cat's stomach, Sirofel™ delayed-release tablets utilize a specialized enteric coating. The tablet must be swallowed whole—never crushed or dissolved—to guarantee target delivery and therapeutic efficacy.