What is the recommended pimobendan, furosemide, and benazepril dosing protocol for dogs with CHF?

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For dogs with congestive heart failure (CHF) due to myxomatous mitral valve disease (MMVD), the standard chronic oral regimen is pimobendan 0.5 mg/kg/day divided q12h, furosemide at the lowest effective dose titrated to clinical response, and benazepril 0.25–1.0 mg/kg PO q24h (or q12h at higher doses). 8101 Pimobendan is dosed at 0.5 mg/kg/day PO divided into two portions administered approximately 12 hours apart. The two portions are not required to be equal.8 In dogs with advanced or refractory CHF, off-label dose escalation beyond 0.5–0.6 mg/kg/day is practiced clinically, with a reported median dose of 0.76 mg/kg/day (range 0.39–1.31 mg/kg/day) in that population.3 Pimobendan should be continued on the day of anesthesia as scheduled.12 Furosemide is the first-line loop diuretic and is titrated to the lowest dose that controls clinical signs. In dogs with advanced CHF, the threshold for adding adjunctive medications is a total daily furosemide dose exceeding 4 mg/kg/day despite concurrent pimobendan and a maximally tolerated angiotensin-converting enzyme inhibitor (ACEI) dose.3 For acute decompensation, furosemide has been administered as an IV bolus of 4 mg/kg followed by repeated doses of 3 mg/kg IV q12h.7 Furosemide should also be continued on the day of anesthesia.12 Benazepril is dosed at 0.25–1.0 mg/kg PO q24h; the low end of this range (0.26–0.58 mg/kg q24h) may be less effective than higher or twice-daily dosing. Evidence suggests the RAAS-mitigating effects of benazepril are dose-dependent, and higher doses may be associated with improved clinical outcomes.510 In dogs with advanced CHF, the ACEI dose may need to be reduced or discontinued if worsening azotemia develops — this occurred in 6 dogs in one advanced heart failure cohort, with discontinuation in 2.3 The clinical benefit of adding an ACEI to dual therapy (pimobendan + furosemide) is not established by prospective survival data. The VALVE trial showed no statistically significant difference in me