Glomerular renal failure

Acute renal failure (ARF) is a potentially life-threatening clinical syndrome that occurs primarily in hospitalized patients and frequently complicates the course of the critically ill. It is characterized by a rapid decrease in glomerular filtration rate (GFR) and the resultant accumulation of nitrogenous waste products (e.g., creatinine and urea nitrogen), with or without a decrease in urine output. A recent consensus statement... 

Acute renal failure (ARF) is broadly defined as a decrease in glomerular filtration rate (GFR) occurring over hours to weeks that is associated with an accumulation of waste products, including urea and creatinine. Clinicians use a combination of the serum creatinine (Scr) value with change in either Scr or urine output (UOP) as the primary criteria for diagnosing ARF. 

These results suggest acute renal failure (ARF) due to tubular necrosis caused by phenol. Plasma sodium is low due mainly to impaired reabsorption in the nephron, although the slightly low albumin suggests haemodilution possibly as a result of excessive i.v. fluids. Potassium is raised due to poor exchange with sodium in the distal tubule and the acidosis (low pH and low bicarbonate concentration) arises from defective acidification of the glomerular filtrate acidosis is often associated with hyperkalaemia (raised plasma... 

Ischemic acute renal failure (ARF), characterized by a sharp decline of glomerular filtration rate, is a very common complication in hospitalized patients and particularly in patients with multiorgan failure. Although it develops most frequently in multimorbid patients, its occurrence per se increases the risk of death by 10- to 15-fold (Ghertow et al, 1998). This unacceptable situation in both diseases warrants the urgent development of new treatment modalities. 

Renal function impairment No changes were observed in the pharmacokinetics of dipyridamole or its glucuronide metabolite with creatinine clearances ranging from approximately 15 mL/min to more than 100 mL/min if data were corrected for differences in age. Avoid aspirin in patients with severe renal failure (glomerular filtration rate less than 10 mL/min). 

Metabolism/Excretion - In the first 24 hours, approximately 75% of a dose is excreted in urine by glomerular filtration. Elimination half-life is 4 to 6 hours in adults and 2 to 3 hours in children. About 60% of an intraperitoneal dose administered during peritoneal dialysis is absorbed systemically in 6 hours. Accumulation occurs in renal failure. Serum half-life in anephric patients is approximately 7.5 days. Vancomycin is not significantly removed by hemodialysis or continuous ambulatory peritoneal dialysis, although there have been reports of increased clearance with hemoperfusion and hemofiltration. 

Of practical importance is the problem of prescribing to the elderly, and to those with co-morbid conditions e.g. greater risk of serious gastroduodenal reactions, high risk of exacerbating cardiac failure and development of renal failure in patients dependent on prostaglandins to maintain glomerular perfusion, dehydration, concomitant use of ACE... 

Extensive literature has accumulated concerning other forms of renal dysfunction during long-term lithium therapy, including chronic interstitial nephritis and minimal-change glomerulopathy with nephrotic syndrome. Some instances of decreased glomerular filtration rate have been encountered but no instances of marked azotemia or renal failure. 

Penicillin is rapidly excreted by the kidneys small amounts are excreted by other routes. About 10% of renal excretion is by glomerular filtration and 90% by tubular secretion. The normal half-life of penicillin G is approximately 30 minutes in renal failure, it may be as long as 10 hours. Ampicillin and the extended-spectrum penicillins are secreted more slowly than penicillin G and have half-lives of 1 hour. For penicillins that are cleared by the kidney, the dose must be adjusted according to renal function, with approximately one fourth to one third the normal dose being administered if creatinine clearance is 10 mL/min or less (Table 43-1). 

Tetracyclines are excreted mainly in bile and urine. Concentrations in bile exceed those in serum tenfold. Some of the drug excreted in bile is reabsorbed from the intestine (enterohepatic circulation) and may contribute to maintenance of serum levels. Ten to 50 percent of various tetracyclines is excreted into the urine, mainly by glomerular filtration. Ten to 40 percent of the drug is excreted in feces. Doxycycline and tigecycline, in contrast to other tetracyclines, are eliminated by nonrenal mechanisms, do not accumulate significantly and require no dosage adjustment in renal failure. 

A portion of absorbed drug is acetylated or glucuronidated in the liver. Sulfonamides and inactive metabolites are then excreted into the urine, mainly by glomerular filtration. In significant renal failure, the dosage of sulfonamide must be reduced. 

Nitrofurantoin is well absorbed after ingestion. It is metabolized and excreted so rapidly that no systemic antibacterial action is achieved. The drug is excreted into the urine by both glomerular filtration and tubular secretion. With average daily doses, concentrations of 200 mcg/mL are reached in urine. In renal failure, urine levels are insufficient for antibacterial action, but high blood levels may cause toxicity. Nitrofurantoin is contraindicated in patients with significant renal insufficiency. 

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