Discussions that mention cimetidine

Thyroid Disorders board


I just found out my PTH is 9.4 (14-72).

First there are two factors to consider that can affect the PTH test. Medications that you are on and the time the test was done.
Drug interactions
Some prescription drugs affect the results of PTH tests. Drugs that increase PTH levels include phosphates, anticonvulsants, steroids, isoniazid, lithium, and rifampin. Drugs that decrease PTH include cimetidine and propranolol.

Timing
PTH levels are subject to daily variation, ranging from a peak around 2:00 A.M. to a low point around 2:00 P.M. Specimens are usually drawn at 8:00 A.M.

Now what does a low PTH mean? Abnormal results
When measured with serum calcium levels, abnormally high PTH values may indicate primary, secondary, or tertiary hyperparathyroidism, chronic renal failure, malabsorption syndrome, and vitamin D deficiency. Abnormally low PTH levels may indicate hypoparathyroidism, hypercalcemia, and certain malignancies (normally a benign tumor on the parathyroid - you have groiters in your thyroid.. it stands to reason you may develop one in/on the parathyroid).

Have they done a targeted scan of the parathyroid yet? Or have they only scanned and looked at the thyroid. Are your nodes hot or cold? I may have given you more questions than answers.. but my knowledge of the hyper side of things is low as well.

MG