Sirolimus Delayed-Release

What is sirolimus delayed-release (Felycin®-CA1)?

Sirolimus delayed-release tablets (Felycin®-CA1) are macrolide agents used to treat hypertrophic cardiomyopathy (HCM) that is subclinical (not yet showing symptoms) in cats. Sirolimus may be referred to as rapamycin.

Sirolimus delayed-release is conditionally approved by the Food and Drug Administration (FDA) in the United States for the management of ventricular hypertrophy in cats with subclinical hypertrophic cardiomyopathy (HCM). 

Any off label (extra label) use or use in other species is prohibited. This medication is not currently available in Canada.

How do I give my pet sirolimus delayed-release?

• Sirolimus delayed-release tablets are given orally (by mouth) once weekly.
• This medication is best given with food.
• Give this medication exactly as prescribed and directed by your veterinarian.

Sirolimus delayed-release is considered a hazardous drug, so it is essential to avoid accidental exposure. Wear gloves when handling the medication and do not handle it if you are pregnant or nursing. If your pet vomits after receiving this drug, wear gloves while cleaning up.

This medication should start to take effect within a few days and effectiveness should build over time. Outward effects may not be noticeable.

What if I miss giving my pet the medication?

If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.

Are there any potential side effects from sirolimus delayed-release ?

Sirolimus delayed-release may cause the following side effects:

• Tiredness

Serious adverse reactions may occur. If any of the following signs develop, stop giving sirolimus delayed-release and contact your veterinarian immediately:

• An allergic reaction such as irregular breathing, rash, fever, puffiness and swelling around the face
• Changes in heart rate, rhythm
• Collapse
• Pale gums
• Difficulty breathing, coughing

Drug sensitivities can develop over time with repeated exposure. Your pet may have no reaction after the first few doses, but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of treatment.

Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately. This medication should stop working within several days, though effects may last longer in pets with kidney and/or liver disease.

Are there any risk factors for this medication?

DO NOT USE sirolimus delayed-release in:

• Cats that are allergic to any component of the medication
• Cats that are already showing symptoms of heart disease or are in heart failure
• Cats with diabetes mellitus or liver disease
• Cats that are pregnant or nursing
• Any species other than cats

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with sirolimus delayed-release:

• Anticonvulsants (e.g., phenobarbital)
• Antifungals (e.g. ketoconazole)
• Antivirals (e.g. acyclovir)
• Certain antibiotics (e.g., neomycin, rifampin, tobramycin)
• Nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., meloxicam)
• Immunosuppressive agents (e.g., methotrexate)
• Other medications used to treat heart disease (e.g., benazepril, digoxin)

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking before starting any new treatment.

Is any monitoring needed with this medication?

• Your veterinarian will let you know when and how they want to reassess your pet to ensure the medication is working and not causing side effects.
• At home, monitor for any side effects such as those noted above. If any occur, stop using the medication and contact your veterinarian.

How do I store sirolimus delayed-release?

• Store according to manufacturer’s directions.
• Keep medication out of reach of children and pets.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet’s weight and symptoms.