title: Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects.
abstract: Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Johansson
authors.forename: Sarah Y
authors.initials: SY
authors.lastname: Gardner
authors.forename: Jay F
authors.initials: JF
authors.lastname: Levine
authors.forename: Mark G
authors.initials: MG
authors.lastname: Papich
authors.forename: D Heath
authors.initials: DH
authors.lastname: LaFevers
authors.forename: Laura R
authors.initials: LR
authors.lastname: Fuquay
authors.forename: Virginia H
authors.initials: VH
authors.lastname: Reagan
authors.forename: Clarke E
authors.initials: CE
authors.lastname: Atkins
mesh_terms: D000818:Animals; D002118:Calcium / Q000652:urine; D002712:Chlorides / Q000652:urine; D018592:Cross-Over Studies; D004232:Diuretics / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D005260:Female; D005665:Furosemide / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics / Q000652:urine; D006736:Horses / Q000097:blood / Q000502:physiology* / Q000652:urine; D007262:Infusions, Intravenous; D010953:Plasma Volume / Q000187:drug effects / Q000502:physiology; D011188:Potassium / Q000652:urine; D012084:Renin-Angiotensin System / Q000187:drug effects; D013046:Specific Gravity / Q000187:drug effects
chemical_list: D002712:Chlorides; D004232:Diuretics; D005665:Furosemide; D011188:Potassium; D002118:Calcium