Side Effects of Pimobendan

Pimobendan is the generic name for a heart medication indicated to help dogs suffering from heart failure. This medication makes it easier for the heart to pump blood throughout a dog's body by dilating the blood vessels and decreasing blood pressure. Pimobendan is administered as a chewable tablet given approximately one hour before feeding, or as directed by a veterinarian. Dog owners should be aware of the potential side effects of pimobendan before giving this medication to their dogs.

Pimobendan can help prolong the life of dogs with heart failure. (Image: Comstock/Stockbyte/Getty Images)

Upset Stomach

The most common side effects of pimobendan are upset stomach symptoms. These symptoms can include vomiting, diarrhea or loss of appetite. In fact, approximately one-third of dogs treated with this medication during clinical trials developed poor appetite or diarrhea side effects, according to Drugs.com. Affected dogs may vomit after eating, or may need to take more frequent trips outdoors due to urgent bowel movement symptoms. A dog treated with this medication may also begin to eat less food than usual, or may be uninterested in snacking on his favorite treat due to a diminished appetite.

Lethargy or Fainting

Treatment with this medication can induce lethargy or fatigue side effects in certain dogs, the Doctors Foster and Smith website explains. A dog owner can notice that her dog isn't as playful as unusual or has difficulty running or playing fetch. Certain dogs can faint or lose consciousness while taking this medication. If such side effects arise, a pet owner should take her dog to a veterinarian for further evaluation and care.

Weakness or Poor Coordination

A dog treated with pimobendan can appear abnormally weak or uncoordinated. Affected dogs may limit their movements throughout the day, preferring to nap or remain lying down due to sensations of body weakness. A dog can appear unbalanced while walking or running due to poor coordination. These side effects of pimobendan may progressively diminish with continued use of this medication.

Breathing Difficulties or Cough

Cough or breathing difficulties can affect dogs taking this medication. In clinical trials for pimobendan, approximately 7 percent of dogs exhibited cough symptoms, Drugs.com reports. A pet owner may notice that his dog begins to wheeze or becomes out of breath quickly due to breathing difficulties.

Sudden Death

Approximately 6 percent of dogs treated with pimobendan during clinical trials experienced sudden death, Drugs.com reports. This medication alters the way in which the heart pumps blood through the body, which increases the risk of potentially fatal side effects. Pet owners should be aware of these risks before giving pimobendan to their dogs.