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Congestive Heart Failure & Diabetes in a Cat

Congestive Heart Failure & Diabetes in a Cat

Elizabeth Rozanski, DVM, DACVIM (Small Animal), DACVECC, Tufts University

Internal Medicine

|January 2015|Peer Reviewed

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STILTON, A 9-YEAR-OLD, OVERWEIGHT DOMESTIC LONG-HAIRED CAT, is hospitalized for pulmonary edema resulting from congestive heart failure (CHF) and diabetes mellitus (DM). Previous treatment included daily oral the- ophylline and monthly methylprednisolone acetate injections for suspected asthma, which may have potentiated the recent onset of CHF and DM. Stilton has had PU/PD for several weeks and vomited once the previous day. Initial examination revealed increased respiratory rate and effort, 180-bpm heart rate with intermittent gallop rhythm, and 1-lb weight loss as compared with 2 months earlier. Chemistry panel confirmed DM (glucose, 535 mg/dL) and identified hypokalemia (potassium, 3.0 mmol/L) but was otherwise unre- markable. CBC was normal. Urinalysis obtained by cystocentesis found 4+ glucose, with WBCs TNTC and occasional bacilli.

Which of the following drugs could be safely administered?

Based on the information provided, how would you grade the following drugs and why? Please click on the red, yellow, or green buttons next to each drug name to indicate its level of safety.

Do Not Use Use Caution Safe


Correct ResponseSafeAntibiotic therapy is indicated in patients with urinary tract infections.1,2 Ampicillin, a broad-spectrum β-lactam antibiotic, is concentrated in urine and does not interfere with treatment protocols for DM or CHF. Side effects are minimal.3 Of note, ampicillin could be administered IV in this vomiting cat. Therapy with potentiated ampicillin (amoxicillin–clavulanic acid) could be considered after vomiting resolves. Antimicrobial choices should be directed by culture and sensitivity data if possible.


Correct ResponseUse CautionAlthough antibiotics are clearly indicated for urinary tract infections, if a patient is receiving theophylline for asthma, toxicity (restlessness, vomiting/ diarrhea, tachycardia) may develop as a result of altered xanthine clearance from concurrent fluoroquinolone administration.4,5 Theophylline toxicity has been shown in dogs and humans but only anecdotally in cats. Enrofloxacin could be administered if theophylline is discontinued.


Correct ResponseUse CautionInhaled glucocorticoids can be useful for controlling allergic airway disease in cats.6 Fluticasone has limited systemic effects and is particularly useful in asthmatic cats with relative contraindications (eg, concurrent heart disease, DM) for systemic glucocorticoids.6,7 In this cat, the decision to start fluticasone should be delayed until CHF and DM are under control and a diagnosis of asthma confirmed.


Correct ResponseSafeThis cat’s CHF may be linked to recent administration of methylprednisolone acetate affecting sodium and water retention, but the presence of pulmonary edema requires administration of a diuretic to eliminate the edema.8,9 Side effects associated with furosemide therapy include excessive dehydration, electrolyte depletion (less common in cats), and azotemia.10 Furosemide administration is indicated by clinical signs rather than a set schedule.10


Correct ResponseDo Not UseWhile antibiotic therapy is indicated for cats with urinary tract infections,1,2 the nephrotoxicity associated with aminoglycosides, particularly in combination with furosemide, makes the risk for kidney injury too high to warrant recommending its initial use.3

Insulin glargine

Correct ResponseUse CautionInsulin therapy is indicated, given the preceding signs of PU/PD and weight loss coupled with hyperglycemia and 4+ glucosuria.11 Regular insulin is typically used initially until the cat is eating and drinking normally. Maintenance treatment with insulin glargine is widely used and can effectively induce diabetic remission in many cats.12

Intravenous fluids

Correct ResponseDo Not UseIV fluid support is often indicated in cats with newly diagnosed DM. However, in patients with CHF, fluid therapy is contraindicated initially, as increased hydrostatic pressure can worsen pulmonary edema.8 Fresh water should be offered regularly.


Correct ResponseUse CautionVomiting and nausea may contribute to persistent anorexia in a diabetic cat. Maropitant, a useful antiemetic with a strong safety profile, will not interfere with treatment protocols for asthma or CHF.13 Because this cat vomited once before presentation, it is reasonable to wait and see if vomiting recurs before administering maropitant; from a drug-interaction perspective, however, it is safe to administer.13

Oral potassium

Correct ResponseSafePU/PD, coupled with decreased oral intake, results in potassium depletion in most diabetics.12 Because IV fluids with potassium supplementation can be challenging in patients with CHF, oral potassium supplementation should be considered in addition to offering palatable foods on a regular basis. This approach is particularly important with furosemide initiation.10

Oxygen therapy

Correct ResponseSafeOxygen therapy is indicated to improve tissue oxygenation and reduce respiratory difficulty.14 Most commonly administered to cats via oxygen cage, oxygen therapy can be discontinued when orthopnea and respiratory distress have been resolved. Thoracic radiography may be useful to determine whether pulmonary infiltrates have cleared.


Correct ResponseUse CautionAlthough pimobendan has been used off-label in cats with increasing efficacy,15,16 until echocardiography confirms the absence of left ventricular outflow obstruction, the use of pimobendan should be avoided.


Correct ResponseDo Not UsePrednisolone is typically considered useful treatment for airway inflammation associated with feline asthma.7 However, most glucocorticoids promote water retention and should not be used in patients with active CHF.7,9 Prednisolone can also lead to insulin resistance, making it more difficult to control newly diagnosed DM.7 Because this cat has active CHF, additional systemic glucocorticoid therapy (eg, methylprednisolone acetate injection) should be avoided unless clearly indicated.

CHF = congestive heart failure, DM = diabetes mellitus

References and Author Information

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