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Heart Medications

Amiodarone
Amiodarone is an anti-arrhythmic medication, which may be used to control multiple types of arrhythmias. It has been shown to potentially convert atrial fibrillation back to a normal rhythm. It is only given once daily, after an initial loading period (higher dose for 5-7 days). Side effects include loss of appetite, vomiting, liver failure (which may be reversible if the drug is stopped) and destruction of platelets by the immune system.

Angiotensin-converting enzyme (ACE) inhibitors
These medications are used to prevent fluid retention. They also help to control some of the hormones that are elevated with significant heart disease and congestive heart failure, as well as prevent fibrosis (scarring) of the heart muscle. Side effects include increases in potassium and kidney values (BUN, creatinine). Either enalapril or benazepril may be used.

Atenolol
Atenolol is a beta blocker. It may be used to control multiple types of arrhythmias. It can also be used for patients with heart disease such as subaortic stenosis, pulmonic stenosis or hypertrophic obstructive cardiomyopathy to slow the heart rate and allow the heart more time to fill with blood. Side effects include lethargy, weakness and loss of appetite. This medication CANNOT be started or stopped abruptly, and the dose is often up-titrated or down-titrated as needed.

Carvedilol
Carvedilol is a beta blocker, which has additional antioxidant effects and helps to dilate blood vessels. It may be used similarly to atenolol, but may also be used in patients with asymptomatic heart disease (although the benefit of this use has not been fully proven). Side effects include lethargy, weakness and loss of appetite. This medication CANNOT be started or stopped abruptly, and the dose is often up-titrated or down-titrated as needed.

Clopidogrel (Plavix®)
Clopidogrel is a medication used to prevent platelet clumping, which is the beginning of clot formation. This medication is typically used in cats with enlarged atria (top chambers of the heart), or in patients who are suspected to have thrown blood clots to their lungs. Side effects are rare; however, bleeding may occur.

Digoxin
Digoxin is an anti-arrhythmic medication, which is often used in conjunction with diltiazem to control supraventricular arrhythmias, including atrial fibrillation. Side effects include loss of appetite, vomiting and diarrhea and abnormal heart rhythms. Digoxin is cleared from the body by the kidneys and can accumulate to toxic amounts in the blood stream when concurrent kidney disease is present.

Diltiazem
Diltiazem is an anti-arrhythmic medication used to control supraventricular arrhythmias, including atrial fibrillation. It must be given three times daily. Side effects include lethargy and weakness.

Diltiazem-extended release
Extended release diltiazem is also used to control supraventricular arrhythmias, including atrial fibrillation. However, it is only given twice daily. The most common formulations used are the name brand medication, Dilacor XR®, and its generic formulation, dilt XR. Side effects include lethargy and weakness.

Furosemide (Lasix®)
Furosemide is a diuretic, which means it helps to remove fluid from the body. It is used primarily to treat congestive heart failure by helping pull fluid out of the lungs. It is also used to help prevent the return of fluid accumulation in the chest or abdominal cavities following removal of this fluid with a catheter. Side effects include increased thirst, urination, increases in kidney values (BUN, creatinine) and decreases in electrolytes, particularly potassium.

Hydrochlorothiazide
Hydrochlorothiazide is a potent diuretic (meaning it helps to remove fluid from the body), which is used primarily in end-state congestive heart failure. It is used in conjunction with furosemide; however, when initiated, the dose of furosemide is cut in half. Side effects include increased thirst, urination, increases in kidney values (BUN, creatinine) and decreases in electrolytes, particularly potassium.

L-carnitine
L-carnitine is a nutritional supplement, which may help to improve heart function. In patients with normal carnitine levels in the bloodstream and heart muscle, this will likely not provide any additional benefit. However, without a biopsy of the heart muscle, patients with carnitine deficiencies cannot be identified, so predicting who will respond to this medication is difficult. Side effects are rare.

Mexiletine
Mexiletine is an anti-arrhythmic medication, which is used to control ventricular arrhythmias. It must be given three times daily. Side effects include loss of appetite and vomiting. In some cases, mexiletine may make arrhythmias worse.

Pimobendan (Vetmedin®)
Pimobendan has two functions. The first is to increase the strength of the heart’scontractions. The second function is to dilate the major blood vessels in the body, which helps to ease the workload on the heart and make it easier for the heart to pump blood forward to the body. Side effects are very rare, but vomiting may occur.

Sildenafil (Viagra®)
Sildenafil is a medication used to treat pulmonary hypertension (high blood pressure in the lungs) by dilating the blood vessels in the lungs. Side effects are rare.

Sotalol
Sotalol is an anti-arrhythmic medication, which has some beta blocking properties. It is used primarily to control ventricular arrhythmias but may also be used to control some other types of arrhythmias. Side effects include lethargy, weakness and loss of appetite. In rare cases, sotalol may make arrhythmias worse.

Spironolactone
Spironolactone has several properties, which are dependent on the dose used. At lower doses, it helps to control some of the hormones that are elevated with significant heart disease and congestive heart failure and prevents fibrosis (scarring) of the heart muscle. At higher doses, it also acts as a diuretic, which means it helps to remove fluid from the body. It is often used in conjunction with furosemide, and is very beneficial in the treatment of ascites (fluid accumulation in the abdominal cavity). Side effects include increases in potassium and kidney values (BUN, creatinine).

Taurine
Taurine is a nutritional supplement,which may help to improve heart function. In patients with normal taurine levels in the bloodstream, this will likely not provide any additional benefit. Side effects are rare.

For more information on this subject, speak to the veterinarian who is treating your pet.