- Author: Moro O Salifu, MD, MPH, FACP; Chief Editor: Vecihi Batuman, MD, FACP, FASN more...
The goals of therapy are to increase renal perfusion and to maintain urine output. Drugs used in the management of patients with azotemia include diuretics, adrenergic agents, plasma volume expanders, and corticosteroids. Specific therapies for various systemic conditions affecting the kidney are discussed in other articles.
Diuretics are used to induce urine output in acute tubular necrosis (ATN) and to treat edema and hypertension. They increase urine excretion by inhibiting sodium and chloride reabsorption at different sites in the nephron.
Furosemide is the drug of choice as a diuretic. It inhibits sodium chloride reabsorption in the thick ascending limb of the loop of Henle.
Hydrochlorothiazide (HCTZ) acts on the distal nephron to impair sodium reabsorption, enhancing sodium excretion. It has been in use for more than 40 years and is generally an important agent for the treatment of essential hypertension.
Chlorothiazide inhibits the reabsorption of sodium in distal tubules, causing increased excretion of sodium and water, as well as of potassium and hydrogen ions.
Metolazone is given as an adjunct to furosemide in severe edematous states or when furosemide alone does not achieve adequate diuresis. It increases excretion of sodium, water, potassium, and hydrogen ions by inhibiting reabsorption of sodium in distal tubules. Metolazone may be more effective in the setting of impaired renal function.
Plasma volume expanders increase plasma oncotic pressure and mobilize fluid from the interstitial space into the intravascular space in hypoalbuminemic patients. They enhance delivery of furosemide to distal tubule.
Albumin is supplied as a 5% solution in 250 mL or a 25% solution in 50 mL. The choice between the 2 formulations is based on whether patient requires additional fluid replacement. Albumin is not used for nutritional supplementation; thus, attempts should be made to improve patient's nutrition.
Corticosteroids are potent anti-inflammatory agents and immunosuppressants. They suppress humoral and cellular response to tissue injury, thereby reducing inflammation.
Prednisone is commonly used for many forms of glomerulonephritis and interstitial nephritis. Once the diagnosis is confirmed, a trial of oral prednisone (starting at 1 mg/kg/day and tapering over 6 weeks) may be considered.
Corticosteroids act as potent inhibitors of inflammation. They may cause profound and varied metabolic effects, particularly in relation to salt, water, and glucose tolerance, in addition to their modification of the immune response of the body. Once the diagnosis is confirmed, a trial of oral prednisolone (starting at 1 mg/kg/day and tapering over 6 weeks) may be considered.
Methylprednisolone decreases inflammation by suppressing the migration of PMNs and reversing increased capillary permeability. In severe cases, a trial of intravenous pulse methylprednisolone (1 g for 3 days) may be considered once the diagnosis is confirmed.
Alpha/Beta Adrenergic Agonists
Adrenergic agents stimulate vasodilation of the renal vasculature and enhance perfusion.
Above a critical dose (renal dose), dopamine becomes a potent vasoconstrictor. Renal-dose dopamine is used widely, but a clear benefit has not been established.
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