Side Effects of Calcium Channel Blockers in Dogs

Calcium channel blockers, such as Diltiazem and Captopril, are prescribed by veterinarians to treat heart problems in dogs, based upon the fact that calcium is an essential element for the heart. A channel blocker slows down the heart rate and the force of contraction by diminishing the amount of calcium ions reaching the heart. Like with many humans, dog patients may have side effects.

  1. GI Tract

    • According to the Merck Veterinary Manual, a side effect of Captopril is distress from gastrointestinal problems, such as vomiting and diarrhea. These symptoms are also listed by Doctors Foster and Smith for the use of Diltiazem and may be related to the calcium blockage in the dog's body.

    Slow Heart Rate

    • Although one purpose of the calcium channel blocker is to regulate the heart beat, a slow heart rate is listed as a side effect because of the fact that slowing the heart down too much can be dangerous. The dog's heart rate must be monitored to make sure it is not too low, which can result in another side effect: low blood pressure.

    Irregular Heart Rates

    • Slowing down the heart rate and decreasing contractions is the desired result, not making the heart beat irregular. This side effect can cause some serious problems for the dog, including weakness or fainting. As with all side effects on the heart, interruption of calcium is most likely the culprit.