Is there an Alternative to Methimazole?
It seems there are always some cats who cannot take methimazole due to side effects and cannot undergo radiotherapy due to expense. An alternative medication called ipodate (an iodine-based radiographic contrast agent) has been investigated. This medication inhibits the conversion of T4 to T3 (unlike methimazole, which inhibits production of T4). In a study of 12 hyperthyroid cats, 8 responded well to ipodate with no negative side effects. More severe cases of hyperthyroidism tend not to respond. This seems like an attractive alternative, except that nearly as soon as the research was published, the product went off the market, having been surpassed in radiology by more efficient contrast media. A similar compound called iopanoic acid appears to be similar in effect to ipodate but is difficult to obtain. It is available through compounding pharmacies, if at all. Another approach for cats who cannot take methimazole involves a combination of potassium iodate and a heart medication calle
