Animal & Veterinary
New Drug To Treat Heart Failure in Dogs Gets OK
by Walt D. Osborne, M.S., J.D., Assistant Editor
FDA Veterinarian Newsletter 2007 Volume XXII, No II
On May 16, 2007, the Food and Drug Administration announced the approval of the first drug to treat congestive heart failure in dogs in over 10 years. The product, Vetmedin® (pimobendan), is approved for managing the signs of mild, moderate, or severe (modified New York Heart Association [NYHA] Class II, III, or IV) congestive heart failure in dogs due to atrioventricular valvular insufficiency or dilated cardiomyopathy. Vetmedin® is indicated for use with concurrent therapy for congestive heart failure as appropriate on a case-by-case basis. The drug, which is sold by veterinary prescription in tablet form, helps alleviate the signs of heart failure by increasing contractility (the force of heart muscle contraction) and by dilating blood vessels (decreasing resistance to blood flow).
Veterinarians classify congestive heart failure according to clinical signs. Class II is mild (fatigue, shortness of breath, and coughing) and is apparent when ordinary exercise is exceeded. Class III is moderate (comfortable at rest, but exercise capacity is minimal). Class IV is severe (no capacity for exercise, and disabling clinical signs are present, even while at rest).
The safety and effectiveness of Vetmedin® were evaluated in a 56 -day, multi-site, active controlled field study with pivotal success determined at day 29. A total of 355 dogs with modified NYHA Class II, III, or IV congestive heart failure due to atrioventricular valvular insufficiency or dilated cardiomyopathy were randomly assigned to either the Vetmedin® treatment group or the active control, Enacard® (enlapril maleate) treatment group. Treatment success in the first group (80.7 percent) was determined to be non-inferior to the treatment success in the second group (76.1 percent).
Vetmedin® is made by MEDA Manufacturing GmbH, Cologne, Germany, for Boehringer Ingelheim Vetmedica, Inc., of St. Joseph, MO.
Adverse reactions associated with Vetmedin® (and Enacard®) were potentially related to congestive heart failure, the therapy of congestive heart failure, or both, and included poor appetite, lethargy, diarrhea, worsening signs of heart failure, heart failure death, increase in the blood urea nitrogen (azotemia), and mild increases in serum liver enzymes.
FDA’s Center for Veterinary Medicine cautions that pimobendan is not intended for use in cats and is only for use in dogs that are diagnosed as explained above. Vetmedin® acts to alleviate the clinical signs of congestive heart failure, rather than to reverse the underlying cardiac pathology. It does not replace the need for other appropriate concurrent heart failure therapy, which includes the use of diuretics and anti-arrhythmic drugs.