Vetsulin, the only FDA-approved insulin for both dogs and cats with diabetes mellitus, is available again more than three years after concerns were raised about the drug’s stability. Merck Animal Health’s reintroduction of Vetsulin (porcine insulin zinc suspension) to the U.S. veterinary market comes as the number of dogs diagnosed with diabetes mellitus has risen sharply over the past 30 years. The prevalence in dogs and cats ranges from 1 in 100 to 1 in 500, Merck stated. Vetsulin is administered twice a day in cats and most dogs. Up to one-third of dogs may be controlled with once-a-day administration. Marketed outside the United States under the brand name Caninsulin, Vetsulin has been used to manage pet diabetes for more than 20 years. It was introduced to the U.S. market in 2004 for canine use and in 2008 for cats. The drug was gradually withdrawn from the U.S. market starting in November 2009 because of inconsistencies in one of Vetsulin’s components, raising fears that the product could have unpredictable onset and duration of action. The issues have been resolved, leading to U.S. Food and Drug Administration approval of Vetsulin’s reintroduction, the manufacturer reported April 23. The drug was produced in 2009 by Intervet/Schering-Plough Animal Health, a subsidiary of Merck & Co. Inc. of Whitehouse Station, N.J., and now part of Merck Animal Health. The withdrawal led to shortages that Intervet managed through a Critical Need Program launched in May 2010. The program continued the flow of Vetsulin to dogs and cats that a veterinarian determined could not use another insulin product. The supply dried up in early 2011. <HOME>