Acute kidney injury due to contrast media occurs more frequently in CKD, diabetic, or elderly patients. Allopurinol is reduced in dosage or discontinued in cases of reduced kidney function. Drug therapy in CKD In reduced kidney function, drugs eliminated by the kidney are not fully metabolized and excreted, resulting in drug accumulation in the blood, which increases the risk of adverse effects. In the case of reduced kidney function, the dose or interval of administration of the drug is adjusted according to the eGFR level.

Nonsteroid anti-inflammatory drugs (NSAIDs) Administration of NSAIDs may further deteriorate kidney function. There are risk factors that facilitate side effects of NSAIDs on the kidney (Table 25-1). NSAIDs may cause acute renal failure, water and Na retention, hypertension, hyponatremia, hyperkalemia, interstitial nephritis, or nephrotic syndrome. COX-2 inhibitors may also injure the kidney, like conventional 3 MA NSAIDs. NSAIDs should be discontinued immediately when drug-induced acute kidney injury is observed. Table 25-1 Risk factors for NSAID-induced kidney damage Low renal blood

flow Low plasma volume Elderly Congestive heart failure Hypertension Nephrotic syndrome CKD Liver cirrhosis Dehydration Low ECFV DM Diuretics Antimicrobial agents Most antimicrobial agents are eliminated RG7204 research buy by the kidney, so they are reduced in dosage in cases of reduced GFR. If the therapeutic concentration of the drug in serum is close to the toxic range, therapeutic drug monitoring (TDM) is desirable. Representative drugs that require TDM (1) Aminoglycoside: acute tubular necrosis occurs with an incidence of 10–20%. Histone demethylase   (2) Vancomycin: interstitial nephritis may occur. It is generally desirable that the trough level is maintained at 10 μg/mL

or less. Its dosage is determined in accordance with renal function and severity of infection.   Antimycotic agents and antivirus agents that require caution (1) Amphotericin B: nephrotoxic.   (2) Antivirus agents (acyclovir, ganciclovir, etc.): psychosis and kidney injury may occur.   Antihyperuricemia agents Hyperuricemia is a risk factor for kidney dysfunction and atherosclerosis. Hyperuricemia is preferably treated even without gouty attacks. The target for the serum uric acid level is less than 9.0 mg/dL, but reducing the serum uric acid level to quickly may induce a gouty attack. Allopurinol: An inhibitor of uric acid synthesis. In the case of reduced kidney function, allopurinol may cause adverse reactions more frequently and may cause prolonged hypouricemia. Start with a low dosage, if administered. The incidence of side effects is high (4%), and severe adverse reactions such as hypersensitivity reaction (including Stevens–Johnson syndrome), agranulocytosis, and hypersensitivity vasculitis may occur. A dosage of less than 50 mg/day is safely administered when the GFR is less than 30 mL/min/1.73 m2.