The Food and Drug Administration (FDA) recently approved pimobendan (Vetmedin, Boehringer Ingelheim Vetmedica) for congestive heart failure (CHF) in dogs due to atrioventricular valvular insufficiency or dilated cardiomyopathy.
Vetmedin is the first drug approved to treat CHF in dogs in more than 10 years, according to the FDA, and is indicated for use with concurrent CHF therapy.
CHF is defined as the heart's inability to function normally, leading to fluid buildup in the lungs. Signs of CHF include fatigue and weakness, decreased ability to exercise, shortness of breath, increased respiratory rate, coughing, weak or irregular pulses, rapid or irregular heartbeats and distended abdomen. Vetmedin helps alleviate signs of CHF by increasing the heart's ability to contract and by dilating blood vessels.
CHF is classified according to clinical signs. Class II is mild (fatigue, shortness of breath, coughing, etc., apparent when ordinary exercise is exceeded); Class III is moderate (comfortable at rest, but exercise capacity is minimal); and Class IV is severe (no capacity for exercise, and disabling clinical signs are present even at rest).
The effectiveness and safety of Vetmedin were evaluated in a 56-day, multicenter, controlled field study with pivotal success determined at day 29. Three hundred fifty-five dogs with modified New York Heart Association Class II, III or IV CHF due to atrioventricular valvular insufficiency or dilated cardiomyopathy were randomly assigned to either the Vetmedin group or the enalapril maleate (Enacard, Merial) group. Treatment success at day 29 in the Vetmedin group (80.7%) was determined to be equivalent to the Ena-card group (76.1%).
Adverse events associated with Vetmedin were similar to those with Enacard and were potentially related to CHF. They included poor appetite, lethargy, diarrhea, worsening signs of heart failure, heart failure death, azotemia and mild increases in serum liver enzymes.
Pimobendan is not for use in cats. Pimobendan acts to alleviate the clinical signs of CHF, rather than to reverse the underlying cardiac pathology.
