This medication should not be used in cats diagnosed with diabetes mellitus. If a cat develops diabetes while receiving treatment, discontinue the medication immediately. It is contraindicated in cats with pre-existing liver disease. Combining this medication with drugs that inhibit cytochrome P-450 3A4 or P-glycoprotein, such as calcium channel blockers, amiodarone, azoles, or cyclosporine, may increase the risk of toxicity. Caution is advised when administering to cats with the MDR1 mutation or when given alongside other P-gp substrates.

Use of this medication may interfere with the cat’s immune response to vaccinations. The safety of this medication has not been established in cats with viral diseases like feline viral rhinotracheitis, other forms of cardiomyopathy, or in those receiving beta blockers or corticosteroids. It should also be avoided in cats with kidney disease, hyperthyroidism, or other serious systemic conditions. Additionally, the effectiveness of this treatment has not been confirmed in sexually intact cats, so it should not be used in animals intended for breeding.

Treatment can lead to elevated levels of liver enzymes, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Blood tests should be performed 1 to 2 months after starting treatment, and then every 6 to 12 months. Discontinue use if enzyme levels exceed twice the normal limit, if other liver enzymes rise, or if symptoms of liver dysfunction appear.

Common side effects observed in cats treated with this medication include cardiovascular issues related to the progression of hypertrophic cardiomyopathy (HCM), such as arrhythmias, congestive heart failure, syncope, and pericardial effusion. Other possible side effects include lethargy, vomiting, diarrhea, and reduced appetite.

This medication is intended for use only in otherwise healthy cats with subclinical HCM, in the absence of other factors that may cause myocardial hypertrophy (e.g., systemic hypertension), and without current or historical symptoms of congestive heart failure, arterial thromboembolism, or severe left ventricular outflow tract obstruction.

This medication is not intended for human use. Keep it out of the reach of children and contact a physician if ingested. Pregnant and breastfeeding women should avoid contact with the medication. It should also be used with caution in individuals who have a known sensitivity to sirolimus.

Store this medication securely to prevent accidental ingestion or overdose by pets or other animals.