(Enalapril, Benazapril)

ACEinhibitors (ACEi) are commonly used medications used as adjunct therapy in the treatment of heart disease. In instances of significant heart disease, hormonal changes in the body result in increased sodium and water retention that may contribute to increased fluid retention and blood pressure. These medications are intended to blunt this hormonal influence and reduce overall water in the body. Additionally, these medication help to slow the progression of cardiac remodeling that may contribute to further progression of heart disease. ACEi’s may also be used as adjunct therapy for the treatment of systemic hypertension (high blood pressure) and in the treatment of certain kidney diseases (protein losing nephropathy). Side effects of this medication are uncommon, but may include decreased appetite, diarrhea, vomiting, and/or exacerbation of underlying kidney disease. Chronic blood monitoring is recommended while on these medications to monitor kidney function while administering these medications.


Amiodarone is an antiarrhythmic medication used in the management of various arrhythmias including supraventricular and ventricular arrhythmias. It also used in patients with atrial fibrillation who are to undergo electrical cardioversion. Side effects of this medication may include gastrointestinal upset such as decreased appetite, vomiting, or diarrhea, or in rare circumstances development or worsening of arrhythmias. Liver and thyroid effects have been reported therefore periodic bloodwork is recommended when receiving this medication. Holter monitoring may be recommended while administering this medication to monitor for any persistent or worsening arrhythmia.


Amlodipine is a drug commonly used to treat patients with systemic hypertension, and may be used as adjunct treatment in the management of mitral regurgitation. This medication belongs to a class of drugs termed “calcium-channel blockers” and as their name suggests the inhibit entry of calcium into muscular cells lining arterial walls. This in turn causes arterial relaxation and reduction in systemic blood pressure. This is often used in conjunction with other blood pressure medications such as ace-inhibitors. Side effects of this medication are rare and typically associated with intended usage. Abnormally low blood pressure can be encountered with excessive dosing and can result in weakness, lethargy, or even collapse. Rarely, gingival hyperplasia can be observed in canine patients on chronically high doses of this medication and may improve or resolve with withdrawal of the medication.

(Atenolol, Sotalol, Carvedilol)

Beta-Blockers (BBs) are commonly used medications in the treatment of multiple conditions associated with the heart. These medications are commonly used anti arrhythmic medications used in the treatment of certain ventricular and supraventricular
arrhythmias. Additionally, this medication may be used in certain obstructive diseases such as Pulmonic or Subaortic Stenosis, or systolic anterior motion of the mitral valve. The intended usage of these medications is to slow heart rate and force of contraction to either reduce the incidence of arrhythmia and/or reduce the pressure generated against a fixed or dynamic obstruction to blood flow. Side effects of these medications are typically associated with their intended usage and may include lethargy, weakness, decreased activity, and/or may precipitate arrhythmias if not already present. Side effects are generally dose dependent therefore dosage adjustments and/or tapering schedules may be recommended while on these medications. Holter monitoring for persistent or worsening arrhythmias may be recommended in cases where arrhythmias are a known concern. This medication should not be stopped abruptly.

(cephalexin, cefpodoxime, cefazolin)

Cephalosporins are a group of antibiotic agents, which cover a wide variety of bacterial infections. Early generation cephalosporins such as cephalexin (Keflex) are effective primarily against gram-positive bacterial infections, however later generation drugs such as cefpodoxime (Simplicef) have broad spectrum against gram positive, grame negative, and anaerobic bacteria. These medications are most commonly used for skin infections and in the peri-operative period following surgery to prevent opportunistic infection from normal skin inhabitants. Side effects of these medications are uncommon, but may include but may include gastrointestinal upset such as decreased appetite, vomiting, or diarrhea.


Clopidogrel is a commonly used medication used in the treatment and/or prophylactic prevention of clotting abnormalities. Clotting abnormalities in animals may develop as a result of abnormal heart enlargement (as in the case of hypertrophic cardiomyopathy in cats), certain endocrine disorders (Cushing’s disease), or certain conditions which predispose to abnormal
protein loss from the body (protein-losing nephropathy or enteropathy). This medication may be recommended when there are known predisposing factors which may contribute to the development of clots in the body that may lead to adverse effects associated with thrombosis (lameness, pulmonary hypertension, stroke, kidney dysfunction). Side effects of this medication are rare and typically associated with intended usage, and may include excessive bruising or bleeding.


Digoxin is medication used to treat certain types of arrhythmias. Digoxin works to slow conduction through the electrical system of the heart to prevent arrhythmias originating in the top chambers of the heart (supraventricular) and/or slow overall heart rate related to atrial fibrillation. Side effects of this medication may include gastrointestinal upset such as decreased appetite, vomiting, or diarrhea, or in certain circumstances development or worsening of certain arrhythmias. This medication has an optimal blood concentration at which it is most effective prior to developing signs of toxicity, therefore contact us immediately if side effects are noted. Chronic blood monitoring may be recommended following initiation of this medication or any dosage adjustments, or if signs of toxicity develop.

(Diltiazem, Diltiazem XR)

Diltiazem is a commonly used anti arrhythmic medication used in the management of certain abnormal heart rhythms (arrhythmias). Diltiazem is commonly used to reduce the frequency with which certain arrhythmias occur (supraventricular) or may be used to slow heart rate in cases of atrial fibrillation. This medication may be administered intravenously in hospital to abruptly stop significant arrhythmias, or may be administered orally for the chronic management of certain abnormal heart rhythms. Side effects of this medication are rare, but may include development or worsening of arrhythmias. Lethargy and decreased appetite have also been reported. This medication may also cause mild weakening of the heart muscle, and therefore may be used with caution in cases where this is a known consideration.

(Furosemide/Lasix/Salix, Torsemide)

Diuretics are medications commonly used in the treatment of congestive heart failure. These medications are intended to target the kidneys to remove excessive fluid from the body, as well as prevent additional accumulation that might result in further clinical signs associated with heart disease. Common side effects of these medications include increased thirst and urination.
Frequently signs of increased urination will subside with time. In some cases (especially in patients with underlying kidney disease), worsening kidney values can be noted. Signs of worsening kidney disease include weakness, lethargy, loss of appetite and vomiting. If any of these signs are noted, please contact us immediately. Chronic blood monitoring is recommended while on diuretic therapy to monitor for the development or worsening of any kidney dysfunction.


Doxycycline is an antibiotic medication with numerous benefits. It is used in the treatment of certain airway infections with microorganisms susceptible to this medication. It also has unique anti-inflammatory properties in the lower airways and may be of some benefit in the management of chronic lower airway inflammation. Doxycycline is also used in the treatment of certain infections transmitted by small insects such as certain rickettsial infections and/or as an adjunct treatment of heartworm infestations. Side effects of this medication are somewhat common and include gastrointestinal upset such as decreased appetite, vomiting, or diarrhea. This medication has also been associated with esophageal inflammation and stricture when lodged in the esophagus, therefore it is often recommended to administer water and/or food following this medication, particularly in cats.


Enoxaparin is a medication that is primarily used to help reduce the risk for intra-vascular (in blood vessels) clot formation secondary to other systemic illness. Enoxaparin is a low-molecular weight heparin and works to inhibit the body’s natural clotting mechanisms. In doing so, cats and dogs with certain types of heart disease or endocrine disease, which may predispose to clot formation (i.e. hypertrophic cardiomyopathy, immune-mediated hemolytic anemia, Cushing’s disease, renal disease, or chronic inflammatory bowel disease) are protected from the adverse effects associated with obstruction to blood flow from clot formation. Intra-vascular clot formation may result in everything from no symptoms to complete paralysis of the hind limbs, renal failure, seizures, etc. This medication is typically provided in a pre-dosed syringe intended for human administration, however due to the small size of veterinary patients, it often must be injected into a separate small sterile vial for smaller sampling using an insulin syringe and given as an injection under the skin. Click here for a step-by-step guide to preparing pre-dosed enoxaparin for administration.  Side effects of this medication are rare in animals, and may include excessive bruising tendencies in animals with hair thinning. Overdoses may result in excessive bleeding such as bleeding from the nose, urinary tract, or gastrointestinal tract, and if these are identified, consultation with a veterinarian is recommended.

(enrofloxacin, marbofloxacin, ciprofloxacin, pradofloxacin)

Fluoroquinolones (most commonly used is enrofloxacin a.k.a. Baytril) are bactericidal antibiotics intended to treat susceptible gram positive and gram-negative infections. These may include infections of the urinary tract, lungs, or other areas where the medication is concentrated. Side effects of this medication are uncommon and generally include gastrointestinal signs such as reduced appetite, vomiting, or diarrhea. Developmental abnormalities may be seen in young animals with this medication and so should be used very cautiously in those animals. Additionally, cats have been reported to experience changes to vision (retinal degeneration) while taking this medication, and so should be used very cautiously in this species as well.


Hydralazine is a medication that is used as adjunct treatment in patients with heart failure due to severe mitral regurgitation. This medication impairs calcium handling within cells in peripheral arteries and arterioles, thus resulting in relaxation of the arterioles and reduced systemic blood pressure. This promotes more forward blood flow. It also may cause increase in heart rate in patients given this medication. This medication is also rarely used as adjunct therapy to treat systemic hypertension, usually in conjunction with other medications (beta-blockers) for those individuals refractory to traditional therapy. Side effects are rare and may include abnormally low blood pressure which may result in weakness, collapse, or lethargy.


Hydrochlorothiazide/HCTZ, Aldactazide 25/25
(Hydrochlorothiazide + Spironolactone)

Hydrochlorothiazide and Aldactazide (hydrochlorothiazide with spironolactone) are potent diuretic medications used as adjunct treatment in the management of congestive heart failure. Common side effects include increased drinking and urination. Electrolyte abnormalities are common with this medication, and therefore close monitoring of kidney blood work is recommended. Side effects associated with worsening renal parameters (lethargy, weakness, decreased appetite, vomiting) can be noted in patients receiving this medication. If noted, please contact us immediately.


Maropitant is a centrally acting anti-nausea medication which blocks signaling in the central nervous system that results in vomiting. This action makes it effective against nausea induced by chemical (toxin), motion (vestibular), and other causes. This medication is intended to be given once daily and not to exceed a total of five consecutive days. Side effects of this medication are very uncommon and typically only include injection site pain and swelling.


Metronidazole is an antibiotic medication typically used to treat diarrhea associated with clostridial overgrowth or stress diarrhea. It also has immunomodulatory effects in the lower intestinal tract that is helpful in reducing intestinal inflammation secondary to stress induced colitis or with certain immune-mediated disease affecting the gastrointestinal tract (inflammatory bowel). It also promotes the development of healthy bacteria in the gut and has probiotic effects. Side effects are very uncommon and may include decreased appetite or vomiting. Rarely and at higher dosages, neurologic affects can be seen with this type of medication, which typically resolve with removal of the medication.

(amoxicillin, ampicillin, penicillin)

Penicillins are one of the oldest forms of antibiotics with the best known being penicillin, and are used against susceptible bacterial infections. The most commonly prescribed penicillins today are typically in the form of combination medications such as amoxicillin + clavulonic acid (Clavamox) to help improve their spectrum of activity against various bacteria. Penicillins are
generally effective against gram-positive bacteria and anaerobic bacteria, however some have good spectrum against some gram-negative bacteria. Side effects of these medications are very uncommons, and typically involve gastrointestinal signs such as decreased appetite, vomiting, or diarrhea. Other rare side-effects may include allergic type reactions similar to humans with
allergies to penicillin.


Pimobendan is a commonly used medication in the treatment of heart disease. This medication works by improving heart muscle function as well as promoting forward blood flow to the body. Through its dual action, this medication is intended to improve heart performance, while reducing workload the heart must endure. This medication is typically used following the onset of congestive heart failure, but has shown some potential benefit at prolonging the onset of congestion in some disease such as in dogs with Dilated Cardiomyopathy and severe Mitral regurgitation. Side effects of this medication are relatively uncommon, and typically gastrointestinal (decreased appetite, vomiting, or diarrhea). This is a beef flavored medication that may be given like a treat. It is not stable in a liquid suspension.

Potassium Supplementation
(Potassi-tabs, Tumil-K)

Potassium supplements are commonly used oral supplements intended to replenish potassium that is lost as a result of chronic or high doses of diuretic administration. Chronic monitoring of electrolytes and renal parameters is recommended while on diuretic therapy and supplementation may be instituted if needed. Side effects of this medication are minimal at normal doses.


Sildenafil is a commonly used medication in the management of severe pulmonary hypertension. This medication helps to relax and dilate arteries in the lungs (pulmonary arteries) and thus reduce the pressure in these arteries. This improves circulation through the lungs and may help reduce clinical signs associated with severe pulmonary hypertension. It also helps to improve right heart function. Side effects of this medication are rare and typically result from intended usage and may include reduced blood pressure. This medication may also increase blood flow into the left side of the heart and so may be used with caution in cases where left heart volume overload is a known consideration.

Sodium Channel Blockers
(Lidocaine, Mexiletine, Procainamide)

These medications are commonly used anti arrhythmic medications used in the management of certain arrhythmias. These medications are intended to reduce the frequency of abnormal heart beats (arrhythmias). They may be administered intravenously in hospital to break life threatening arrhythmias, or may be administered orally for chronic management of significant arrhythmias. Side effects of these medications may include gastrointestinal upset such as decreased appetite, vomiting, or diarrhea, or in rare circumstances development or worsening of arrhythmias. Giving these medications with a meal may help to limit gastrointestinal side effects. Holter monitoring is recommended prior to and while administering this medication to monitor for any persistent or worsening arrhythmia.


Spironolactone is a commonly used adjunct treatment in the management of congestive heart failure. Spironolactone has multiple effects, including reducing the progression of heart remodeling that leads to worsening heart disease, reducing hormonal influence that causes the body to retain water in cases of significant heart dysfunction, as well as weak diuretic properties that function synergistically with furosemide. The purpose of this medication is to slow the progression of heart disease, as well as reduce overall water in the body to treat and/or prevent the development of clinical signs associated with heart disease. It can also help treat common electrolyte abnormalities (ie. low potassium) associated with chronic furosemide administration. Side effects in dogs are uncommon. In cats, facial excoriations are rarely reported, as well as electrolyte disturbances or exacerbation of underlying kidney dysfunction.

Steroidal Anti-inflammatories
(prednisone, prednisolone, dexamethasone, fluticasone)

Steroidal anti-inflammatory medications are typically used in certain inflammatory conditions that are not associated with infectious agents. These medications may be used in certain auto-immune disorders (IMHA, IMTP, immune-mediated arthritis, systemic lupus) or disorders in which there is abnormal inflammation (chronic bronchitis, allergic dermatitis, feline asthma, or as adjunct treatment in the treatment of heartworm infestation). These medications blunt the immune response and reduce inflammation, and are not typically used in cases where there is known infection or where suppression of the immune system may lead to exacerbation of other systemic conditions. They may also increase risk for Diabetes in some patients and can
exacerbate heart failure in patients with heart disease. Common side effects of this medication include increased thirst, increased hunger, more urination, weight gain, and muscle loss. Other, less common side-effects may include gastrointestinal upset such as decreased appetite, vomiting, or diarrhea, or rarely may predispose individuals to infections or delay healing


Theophylline is a medication used in the chronic management of lower airway inflammation and constriction. Theophylline is a methylxanthine derivative in the same family as caffeine that causes relaxation and dilation of the lower airways. It is often used in the chronic management of diseases predisposing to lower airway constriction (chronic bronchitis, pulmonary fibrosis, and pulmonary hypertension) to dilate small airways and improve oxygenation. Side effects are somewhat common and usually gastrointestinal (loss of appetite, vomiting, diarrhea). Hyper-excitation/agitation is also relatively common, but usually dose dependent. Theophylline can also increase heart rate and is sometimes used in patients with a slow heart rate (sick sinus syndrome).


Tylosin is an antibiotic medication, typically administered as a powder in capsules or food. It is typically used with susceptible gram negative and gram-positive bacterial infections. Tylosin also has immunomodulatory effects in the lower intestinal tract that is helpful in reducing intestinal inflammation secondary to stress induced colitis or with certain immune-mediated disease affecting the gastrointestinal tract (inflammatory bowel). It also promotes the development of healthy bacteria in the gut and has probiotic effects. Side effects are very uncommon and may include decreased appetite or vomiting.