Brand name meds are a must at times

Dear Dr. Roach: I just read your article that there wasn’t any difference between Synthroid and levothyroxine. I come from a family with severe sensitivities, allergies and asthma. I was started on Synthroid and did well. My insurance decided not to pay for it, so my doctor switched me to levothyroxine. I developed severe rhythm problems and shortness of breath. I went through the whole cardiac workup and nothing was wrong. My allergist and endocrinologist agreed that the fillers used were probably the cause. They both said to place me back on Synthroid, but I had the same reaction again a couple of years later. Please don’t make me feel like a drama queen when the reaction was real and terrifying. — K.W.

I’m sorry I made you feel like a drama queen. The comparison I made between brand-name Synthroid and generic levothyroxine referred to the active ingredient, which is identical, and I said the manufacturers are held to the same standards of purity and exact dosing.

However, the additional components of the pill, called excipients, occasionally do cause untoward reactions in some people who take them. These could happen with just one manufacturer, generic or brand name. In that case, it is critical to continue taking the medication coming from the manufacturer that is tolerated.

Many people wrote me noting that only brand-name Synthroid was effective for them. I am not able to say whether the reason is the other ingredients, small differences in dosing or bioavailability, or the patient’s expectations.

Everybody we see is unique, and may have some idiosyncratic reaction to a medication, an unusual presentation to an illness or a rare disease. Physicians must be ready to see what doesn’t fit the usual pattern.