Remdesivir

What is remdesivir?

Remdesivir is an antiviral medication used to treat feline infectious peritonitis (FIP).

Its use in cats is considered off label (extra label). Many drugs are commonly prescribed for off-label use in veterinary medicine. “Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How is remdesivir given?

• Remdesivir is given in the form of an injectable solution either under the skin (subcutaneously) or directly into a vein (intravenously).
• If subcutaneous injections are recommended at home, follow your veterinarian’s instructions for dosing and administration closely and contact them right away with any concerns.
• Use appropriate hand hygiene when handling this medication.
• Your veterinarian may recommend switching to an oral medication called GS-441524 after only a short period of remdesivir treatment.

This medication should take effect within 1 to 2 hours and improvement in clinical signs may be seen in as few as 2 to 5 days, with obvious improvement in 1–2 weeks.

What if I miss administering a dose of remdesivir?

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?

Remdesivir may cause the following side effects:

• Pain during administration
• Reaction at the injection site (i.e., redness or swelling)
• Short periods of nausea or depression a few hours after administration
• Mild increase in one liver enzyme (ALT)
• Mild elevations in some white blood cell lines (eosinophils, lymphocytes)

Drug sensitivities can develop over time, with repeated exposure. Your cat 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 short-acting medication should stop working within 24 hours, although effects may be longer in cats with liver or kidney disease.

Are there any risk factors for this medication? 

DO NOT USE in cats who are: 

• Allergic to it or medications like it, such as GS-441524

USE WITH CAUTION in cats who are:

• Pregnant or nursing

More risk factors may be revealed with increased use of the product. Consult with your veterinarian if you are concerned about its use for your cat.

Are there any drug interactions I should be aware of? 

Although not proven, certain medications may interact with remdesivir, including:

• Hydroxychloroquine
• Itraconazole

It is important to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your cat 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. 
• If your cat is being treated at home, monitor them closely for any changes, including improvements or side effects such as those noted above. Contact your veterinarian with any changes.

How do I store remdesivir?

• Store in the refrigerator between 36°F and 46°F (2°C and 8°C). 
• Follow directions on the package carefully to prepare the solution for injection.
• Keep the container out of reach of children and pets.  
• Store compounded forms of this medication according to the label. 
• Ask your veterinarian for specific disposal instructions. Do not flush medicines down the sink or toilet unless instructed to do so.

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.