Furosemide
Acute Cardiac Disease
Initial Dosing
If dyspnoea associated with a significant pleural effusion is identified, we recommend thoracocentesis is considered; then, we recommend a FONS protocol [Furosemide-Oxygen-Nitroglycerine-Sedation] in line with major species extrapolation (DeFrancesco, 2013). Clinicians should avoid diuretic administration until patients are adequately hydrated (Abbott & Kovacic, 2008).
Furosemide: 5 mg/kg IV, then 1-2 mg/kg IV/IM q6-8h for maintenance or a CRI (max 12 mg/kg/d)
Oxygen: Where possible, provide an oxygen chamber with minimal patient restraint, in preference to a mask or flow by.
Nitroglycerin (Glyceryl Trinitrate): 0.25–1.0 cm of a 2% transdermal ointment q 8–24 h for 1–2 d
Sedation: Butorphanol 0.1–0.2 mg/kg IV or IM PRN
Subsequent Dosing
The literature poorly describes ongoing furosemide dosing. Recent publications suggest 1-2 mg/kg PO q8-24h (Hedley, 2023; Watson, 2011).
After applying initial stabilisation measures, we recommend additional post-FONS options, such as pimobendan with or without additional diuretics (DeFrancesco, 2013).
Recommendation Strength
Weak: Despite inadequate evidence for accurate diagnosis of AHF, staging metrics, and efficacy data, we consider furosemide a beneficial medicine and offer dosing suggestions as weak recommendations. Recommendations identified in the literature are also anecdotal or major species extrapolations [MSE], as no controlled study data is available (Müller and Mancinelli, 2022; Ozawa et al., 2021; Pariaut, 2009; Reusch, 2005).
Sole Use
Diuretic monotherapy in the management of acute cardiac failure in most mammalian species is not encouraged, as patients receiving diuretics alone may deteriorate more rapidly than those receiving additional treatment modalities.
Multimodal Use
We recommend extrapolating ACVIM consensus guidelines in rabbit heart failure and considering using Pimobendan or Benazepril.
Efficacy Profile
Our literature searches were unable to identify adequate data to comment on efficacy.
Treatment Goals
Furosemide therapy is used in left-sided cardiac disease to relieve congestion from pulmonary oedema, control Na and fluid retention, and improve cardiac performance. This will improve patient comfort and prolong the length and quality of life of rabbit patients presenting with AHF (Watson, 2011).
Organ Level: Treatment aims to reduce oedema and ascites and improve organ function.
Patient Level: The treatment objective is to increase patients' quality and quantity of survival time and to slow, halt or reverse the disease progression.
Client level: The goal of treatment is to offer clients with rabbits experiencing AHF a value-for-money increase in beneficial survival time.
Treatment End Point
The duration of treatment is patient-specific. No consensus guidelines are available at this time.
Therapeutic Monitoring
Assessing the quality of life of rabbits with AHF relies upon a subjective, case-by-case judgement.
All patients will benefit from regular physical assessments covering heart rate and quality, respiratory rate and effort (resting and sleeping), blood pressure, signs associated with oedema, thirst, urine output, and weight.
Improvements in vital signs may include reduced cardiac and respiratory rates, improved perfusion characteristics and improved activity and cognitive function.
Sonographic assessment of cardiac architecture and remodelling may help with disease staging.
ECG assessment may assist clinicians in the evaluation of rhythm disturbances.
Where funds and facilities allow, additional monitoring may include renal, hydration, and serum electrolyte status.
Alternative Products
Comparative benefits of alternative diuretics such as torasemide remain poorly investigated.
Alternative Protocols
Consensus on even basic cardiac therapeutics is lacking in the rabbit; therefore, we cannot offer alternative protocols for comparison at this time.
AHF References
DeFrancesco, T.C., 2013. Management of Cardiac Emergencies in Small Animals. Veterinary Clinics of North America: Small Animal Practice 43, 817–842. https://doi.org/10.1016/j.cvsm.2013.03.012
Hedley, J., 2023. BSAVA Small Animal Formulary Part B: Exotic Pets.
Palmero, A., 2023. Respiratory distress in a domestic rabbit (Oryctolagus cuniculus). Emerging Animal Species 6, 100022. https://doi.org/10.1016/j.eas.2023.100022
Pariaut, R., 2009. Cardiovascular Physiology and Diseases of the Rabbit. Veterinary Clinics of North America: Exotic Animal Practice 12, 135–144. https://doi.org/10.1016/j.cvex.2008.08.004