Download hyperthyroidism treatment

Client Fact Sheet #118
HYPERTHYROIDISM TREATMENT
Now that your cat has been diagnosed with Hyperthyroidism, it is time to consider treatment options.
There are four treatments that we recommend.
Vidalta Tablet Therapy
Vidalta normally comes as a tablet and needs to be administered once daily, by mouth, for the rest of
your cat’s life. This drug blocks the production of thyroid hormone.
Methimazole Spot-On Gel Therapy
Methimazole Spot-On is a gel that is applied to your cat’s ear flap once a day, for the rest of your
cat’s life. This drug also blocks the production of thyroid hormone.
Iodine 131 Therapy (AVS do not provide this service, we would refer you to an approved
provider)
This treatment involves the injection of Iodine 131 (a radioactive version of normal Iodine). The
Iodine 131 becomes concentrated in the thyroid gland, naturally, and the radiation destroys the
surrounding abnormal thyroid tissue. The dose of radiation is very small so it does not affect the rest
of the cat’s body. Iodine 131 is also used for the treatment of hyperthyroidism in people. It is
normally a one off treatment.
Hill’s Prescription Y/D Diet
A prescription food with low iodine levels to control excess thyroid hormone production. This would be
your cat’s only food for the rest of their life.
Vidalta Tablet Therapy
Advantages
• Treatment can be stopped if any side effects occur.
• No hospitalisation is required
• Side effects are relatively uncommon
Disadvantages
• Tablets need to be given every day and some cats are extremely difficult to give tablet
medication to.
• Side effects such as lethargy, loss of appetite, vomiting, diarrhoea or skin irritation can occur.
Typically these side effects will resolve when the Vidalta is stopped.
Treatment Protocol
The normal treatment protocol with Vidalta is to start the patient on one tablet per day. Three weeks
later a blood test is done to measure its effectiveness by checking the thyroid hormone level.
Updated May 2015
If the thyroid hormone level comes back within the normal range, we would then continue the Vidalta
daily. If the level is not within the normal range we will adjust the dose of medication and re-test
again three weeks later. This repeat testing will be ongoing until results are in the normal range.
Once we have the correct dose rate, we will wait three months and then perform blood tests to check
the thyroid hormone level and also how well the kidneys are functioning. These kidneys tests are
important as hyperthyroidism can mask kidney problems.
If these test results are normal then we will go onto six monthly reassessments of the patient.
Approximate Cost of Vidalta Therapy
Vidalta Tablets 15mg (28 days supply)
Each thyroid hormone blood test (T4)
Kidney biochem blood test
Physical examinations
Average yearly cost for Vidalta therapy
$65.27
$92.00
$80.42
$54.90
(Exam x 2, T4/Kidney test x2, 12mth supply Vidalta)
$1237.88 approx
(if done at same time as T4 blood test)
Methimazole Spot-On Gel Therapy
Advantages
• Treatment can be stopped if any side effects occur.
• No hospitalisation is required
• Side effects are relatively uncommon
• Good option for cats that are difficult to give tablet medication to.
Disadvantages
• Side effects such as lethargy, loss of appetite, vomiting, diarrhoea or skin irritation can occur.
Typically these side effects will resolve when the Methimazole Spot-On is stopped.
Treatment Protocol
The normal treatment protocol with Methimazole Spot-On is to start the patient on one application
per day. Three weeks later a blood test is done to measure its effectiveness by checking the thyroid
hormone level.
If the thyroid hormone level comes back within the normal range, we would then continue the
Methimazole Spot-On daily. If the level is not within the normal range we will adjust the dose of
medication and re-test again three weeks later. This repeat testing will be ongoing until results are in
the normal range.
Once we have the correct dose rate, we will wait three months and then perform blood tests to check
the thyroid hormone level and also how well the kidneys are functioning. These kidneys tests are
important as hyperthyroidism can mask kidney problems.
If these test results are normal then we will go onto six monthly reassessments of the patient.
Approximate Cost of Methimazole Gel Therapy
Methimazole Spot-On Gel (monthly average cost)
Methimazole Spot-On Gel
Each thyroid hormone blood test (T4)
Kidney biochem blood test
Physical examinations
Average yearly cost for Methimazole Spot-On Gel
(Exam x 2, T4/Kidney test x2, 12mth supply Methimazole Spot-On)
$126.91
$126.91 (per 3x tube supply)
$92.00
$80.42 (if done at same time as T4 blood test)
$54.90
Therapy
$1977.56 approx
Updated May 2015
Iodine 131 Therapy (AVS do not provide this service, we would refer you to an approved
provider)
Advantages
• Treatment is a one time event and no on-going therapy is required
• The hyperthyroidism is cured not just managed
Disadvantages
• The cat needs to be hospitalised for a period of seven to nine days while the Iodine 131 is
excreted from its body.
• Not a good therapy for cats with poor kidney function. Hyperthyroidism can mask poor kidney
function. It is for this reason that a month of Vidalta treatment will normally be given prior to
giving Iodine 131. If poor kidney function is present it will normally show up while the cat is on
the Vidalta therapy.
• A small number of cats, normally less than 4%, may require more than one treatment with
Iodine 131.
Cost of Iodine 131 Treatment
Repeat of kidney biochem & urine check 2 weeks prior to treatment (if not done recently)
Iodine 131 treatment
Consultation + 1 month supply Vidalta treatment
$188.00
$870.00
$120.17
One off total cost of
$1178.17
Hill’s Prescription Y/D Diet
Advantages
• Convenient way to manage hyperthyroidism without the need for daily medications
• No hospitalisation is required
• No side effects
Disadvantages
• Food must be fed exclusively
• May not be as effective as Vidalta/Methimazole Spot-On or Iodine 131 treatments
Treatment Protocol
The normal treatment protocol with Hill’s Prescription Y/D is to start feeding the patient Y/D over a
transitional period of 7 days until the patient is eating Y/D exclusively. A thyroid blood test should be
done 4 weeks after Y/D has been fed exclusively and again at 8 weeks. Thyroid levels should come into
normal range within 4-12 weeks of feeding Y/D exclusively. Once the thyroid levels are in the normal
range the thyroid and kidney blood tests should be done 6 monthly. Cats with other diseases e.g.
kidney or cardiac disease may require testing more frequently.
Approximate Cost of Hill’s Prescription Y/D
Hill’s Prescription Y/D biscuits (monthly average cost)
(Hill’s Prescription Y/D 1.8kg $46.73 per bag)
Each thyroid hormone blood test (T4)
Kidney biochem blood test
Physical examinations
Average yearly cost for Hill’s Prescription Y/D
(Exam x 2, T4/Kidney test x2, 12mth supply Hill’s Y/D)
$32.71
$92.00
$80.42
$54.90
(if done at same time as T4 blood test)
$875.21 approx
All treatment costs outlined above are guidelines only and are subject to change without notification
If you have any questions, please ask one of our experienced staff or phone us on 818 5697
Updated May 2015