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BI reportedly stops U.S. sales of Mexitil, sparking concern from veterinarians

Teva Pharmaceuticals USA might be nation’s only maker of mexiletine hydrochloride

October 8, 2009
By Jennifer Fiala

Widespread reports have surfaced that Boehringer Ingelheim Pharmaceuticals (BI) is no longer is manufacturing Mexitil (mexiletine hydrochloride) for the U.S. market, and the move has some veterinarians seeking more information.

In investigating the perceived shortage, the VIN News Service has confirmed that Teva Pharmaceuticals USA makes a generic version of the drug, which is sold through distributors. 

The news was relayed on a Veterinary Information Network (VIN) message board, as veterinarians discussed a case of a boxer diagnosed with arrythmia and dilated cardiomyopathy. Intended for human patients, the drug is an orally active antiarrhythmic agent commonly used by veterinarians to treat ventricular arrhythmias in canine patients.

Dr. Mark Kittleson, a VIN consultant and board-certified cardiologist at the University of California, Davis School of Veterinary Medicine's Department of Medicine and Epidemiology, considers mexiletine to be “reasonably important” to the canine cardiac patients. With no such drug approved for use in veterinary medicine, Kittleson expresses regret that antiarrhythmics are vanishing from the marketplace.

“Oral administrations have disappeared because they’re not being used much in human medicine anymore,” he explains. “They have the reputation of being proarrhythmic and actually causing sudden death.”

He adds that automatic implantable cardioverter defibrillators are replacing the need for antiarrhythmics like mexiletine hydrochloride on the human side. Because of costs associated with the devices, technical issues associated with inappropriate activation and a canine’s shorter life span, they have not found a niche in veterinary medicine.

Repeated phone calls and e-mails to at least seven members of BI’s media relations department resulted in a meager amount of information, pointing toward the possibility that BI might have stopped manufacturing Mexitil due to slow sales. When inquiring for confirmation that the drug is no longer being manufactured, a BI spokeswoman relayed that she needed more time to hunt down that information, acknowledging: “It’s not one of our branded products here in the U.S. that anyone here has heard of. It’s not like Spiriva or Flomax.”

FDA’s Orange Book reports that generics manufacturers Teva Pharmaceuticals USA and Watson Labs also make mexiletine, although a Watson representative says the company is no longer producing the drug.

Teva offers capsules in 150-mg, 200-mg and 250-mg strengths. Reports from at least one veterinarian suggest that Teva's 150-mg strength capsules have been on backorder since July, but the VIN News Service could not confirm that.

While some distributors still have stock of BI’s Mexitil — Midwest Veterinary Supply reportedly received a Sept. 4 order — others are running low. AmerisourceBergen is out of 150-mg and 250-mg strengths and has just 42 bottles of 200-mg strength Mexitil available.

Wedgewood Pharmacy confirms that it sells the drug in eight compounded formulations, including seven capsules and one oral suspension.

VIN News Service commentaries are opinion pieces presenting insights, personal experiences and/or perspectives on topical issues by members of the veterinary community. To submit a commentary for consideration, email

Information and opinions expressed in letters to the editor are those of the author and are independent of the VIN News Service. Letters may be edited for style. We do not verify their content for accuracy.


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