An isotonic, polyionic fluid such as lactated Ringer's solution (LRS) or Plasma-Lyte A (Baxter) may be administered initially.
If hyperkalemia is present or suspected, a potassium-free fluid such as 0.9 percent sodium chloride is indicated. After rehydration,
the type of fluid should be adjusted based on the animal's fluid and electrolyte status. Maintenance fluids with less sodium,
such as half-strength LRS or 0.45% sodium chloride in 2.5% dextrose, may be appropriate for long-term therapy.
Metabolic acidosis can occur in ARF, although alkalinizing therapy is not recommended unless the blood pH is less than 7.2
or the serum bicarbonate is less than 14 mEq/l after correcting fluid deficits.
Moderate to severe life-threatening hyperkalemia may occur if the animal is oliguric or anuric. Animals with severe hyperkalemia
associated with cardiovascular abnormalities should receive specific therapy to reduce serum potassium levels. Hypokalemia
may occur during the diuretic phase of ARF. Therapy consisting of IV or oral potassium chloride is indicated if the serum
potassium concentration is below the normal range, although clinical signs are not usually apparent until it falls below 2.5
Vomiting can be a significant problem in animals with ARF. Because uremia results in hypergastrinemia, drugs that inhibit
gastric acid production are indicated. These include histamine receptor antagonists such as famotidine (0.5-1.0 mg/kg q24h,
PO, IV) and proton pump inhibitors such as omeprazole (0.7 mg/kg q24h, PO), or lansoprazole (0.6-1.0 mg/kg q24h, IV). Centrally
acting antiemetics may also be necessary. Metoclopramide, a dopamine antagonist, may be given as intermittent therapy at a
dose of 0.2 to 0.5 mg/kg q8h IV or as a CRI at 1-2 mg/kg/day IV. Other centrally acting drugs include dolasetron (0.6 mg/kg
q24h, PO or SQ, or diluted in compatible IV fluid and administered over 15 min IV) and ondansetron (0.1-0.2 mg/kg q8h, SQ
or 0.5 mg/kg IV loading dose, then 0.5 mg/kg/hr CRI). Phenothiazine derivative antiemetics such as chlorpromazine (0.2-0.5
mg/kg q6-8h, SQ, IM or IV) can be tried if vomiting persists despite other therapy.
Arterial hypertension may occur in animals with ARF, and can be due in part to fluid overload.
Treatment may include reducing the rate of IV fluids, administration of diuretics and dialysis to remove excess fluid if the
animal is oliguric or anuric.
Pharmacologic treatment is limited because most antihypertensive drugs are available only in oral formulations, and the vomiting
associated with ARF often precludes oral medication. If hypertension is severe, parenteral antihypertensives include nitroprusside
(initial dose 1-2 mcg/kg/min CRI IV; titrate up q5min to achieve desired blood pressure) and hydralazine (0.5-3 mg/kg q12h
IV or 0.1 mg/kg loading dose IV, then 1.5-5 mcg/kg/min CRI IV). Administration of both drugs requires close monitoring. Oral
antihypertensives include amlodipine (0.1-0.25 mg/kg q12-24h, PO in dogs, 0.625-1.25 mg/cat q24h PO in cats) and angiotensin-converting
enzyme (ACE) inhibitors such as enalapril (0.25-0.5 mg/kg q12-24h PO) and benazepril (0.25-0.5 mg/kg q24h, PO). ACE inhibitors
have been associated with worsening of renal function in humans.
Nutritional support has been shown to be important for recovery from ARF. These animals are in a state of negative nutritional
balance at a time when protein and energy are needed to support regeneration of damaged renal tissue. Enteral nutrition, utilizing
an esophagostomy or gastrostomy tube, can be used if the animal is not vomiting; otherwise, parenteral nutrition is indicated.
Management of oliguria or anuria