Upon discharge, your cat will still be minimally radioactive. Even though the level of radioactivity is very low (much lower than the level at which human patients are discharged from the hospital), you should still exercise the following safety precautions for two weeks after discharge:

• You may cuddle with your cat for 20 minutes per day. You can have these 20 minutes all at once, or spread out throughout the day.

• Fortunately, you can pet your cat at an arm’s-length distance as much as you want; this is a safe distance.

• Your cat may not be on your bed while you sleep.

• Your cat should not be near children or pregnant women.

If you or a family member is pregnant, you cannot prevent contact between your cat and children, or you cannot keep your cat from sleeping on the bed with you at night, we recommend that your cat be boarded with your veterinarian during these two weeks.

Release Information for You and Your Hyperthyroid Cat After Treatment with Radioiodine Click here to watch the video

Your cat will excrete much of the residual radioactivity through urine and feces. Therefore, during the first 2 weeks after your cat has been discharged from Hypurrcat, you should either flush the soiled litter down the toilet or store it until it is no longer radioactive. During this initial 2-week period, you must never put waste collected in the regular trash!

To flush your cat’s litter, you must use an appropriate litter. Although there are many brands of litter, we use the "World's Best Cat Litter" at Hypurrcat (clumping formula, green and black bag), so your cat will be accustomed to that brand. You can purchase the World's Best litter at many local pet stores.

You should scoop the litter box at least once or twice a day. You should wear disposable latex gloves when changing the litter and wash your hands after you flush it. Once the 2-week period is over, you should wash the litter pan and litter scoop with soapy water and flush this wash water down the toilet. It is not necessary to discard these items.

If you do not wish to flush the soiled litter down the toilet, the radioactive cat litter can be stored for a 3-month period to allow it to decay down completely to nonradioactive levels. To store the litter, you should collect all the soiled litter for the first 2 weeks after treatment and place it into a heavy garbage bag, tying it securely. To help prevent odors, it is best to double bag the soiled litter. Place the double-bagged soiled litter in a large trash container with a tightly sealed, locked lid. During the time you store the container, place it in an area where it cannot be reached by small children, pets, wild animals, etc. (e.g., a basement, garage, or yard). Do not place it in your kitchen, bedroom, or other frequently occupied areas. After storing this litter for a 3-month period, the bagged cat litter can be disposed of as regular trash because it will no longer be radioactive.

The amount of radiation remaining in your cat is extremely low. In fact, human patients can receive up to 15 times our average cat dose of radioiodine and still go home on the day they get treated. The major reason for this discrepancy between cats and people is that human patients always flush their waste down the toilet, removing any radioactive contamination from the home. In contrast, cats generally use a litter box, keeping the radiation in the home.

Your cat has already excreted the vast majority of the radioiodine in urine and feces while your cat was at Hypurrcat during the first 5 to 10 days after treatment. Therefore, while these discharge instructions may seem alarming, they are an extremely cautious and conservative approach. If you or any of your family were to receive radioiodine therapy, the restrictions after treatment would be much less severe. If you follow our instructions, you and your family will receive almost no exposure whatsoever.

The amount of radiation that your other pets will receive by contact with your cat or by using the litter box is negligible. If you have multiple cats sharing the same litter box, however, we do recommend that you clean the box at least 2 to 3 times a day to remove the contaminated litter clumps from the box. Based upon Federal, State, and City guidelines, you do not need to quarantine your cat from other pets.

If you know that you cannot follow the recommended safety precautions (e.g., if you are pregnant or cannot avoid prolonged close contact, flush the litter, etc.), we recommend that you board your cat with your regular veterinarian during this 2-week period. Their staff would follow the same radiation safety guidelines you would, including properly handling the cat litter and avoiding close, prolonged contact with your cat.

After you pick up your cat from Hypurrcat, we will send your veterinarian a letter summarizing your cat’s treatment and recommending monitoring strategies. Your veterinarian can also contact us if he or she has any further questions.

When are the recommend follow-up times for monitoring after radioiodine?

After discharge from our Hypurrcat facility, your  cat should be monitored at 1, 3, 6 and 12 months, and then every 6 months thereafter. Of course, if your cat isn’t doing well at any time (this is not expected), an earlier recheck is always recommended.

What follow-up monitoring is recommended? What tests should be done?

At each recheck time, we recommend that your cat have a complete physical examination (including a blood pressure reading) and blood tests performed. These recheck(s) should be done by your regular veterinarian. In general, the laboratory testing to perform at these times include a serum chemistry panel, including creatinine and urea nitrogen (two kidney function tests) and a serum thyroid testing (T4 and TSH concentrations).

If your veterinarian emails your cat’s recheck laboratory results and brief clinical history, Dr. Peterson will provide you and your veterinarian an interpretation of these test results, as well as his recommendations.

Download our Monitoring and Follow-Up Guide here.

Your cat’s behavior may change within a few weeks, but some cats require as much as 3 to 6 months for all the clinical signs to disappear. As the metabolic rate returns to normal, body functions slow down. Your cat will become calmer. Along with a slower heartbeat and respiration, changes may include weight gain, better grooming, less vomiting, reduced appetite, fewer visits to the litter box, and more sleeping. Some cats gain one or more pounds in the first month, whereas other cats put lost weight back on more slowly.

Click here for our guides to dietary management for hyperthyroid cats. The dietary guides are at the bottom of the page.