21st March 2024

Renal impairment

In those with renal impairment absorption, distribution, metabolism and elimination are all impaired. There is an overall increased risk of adverse drug reactions in part due to the accumulation of active metabolites and reduced secretion and resorption.

NSAIDs and COX II inhibitors should be avoided as they can lead to reduced glomerular filtration rate and acute interstitial nephritis. One should be cautious using opioids, tramadol, gabapentinoids and benzodiazepines as these may accumulate and lead to sedation and respiratory depression.

Nitrates and rate controlling antihypertensives should be used with care as may worsen renal hypoperfusion and the latter cause bradycardia. Digoxin and ACEi in settings of acute renal impairment can exacerbate hyperkalaemia. Thiazides, loop diuretics and potassium sparing diuretics can lead to electrolyte imbalances. Contrast media can have a direct tubular toxic effect, where appropriate patients should be hydrated before and after contrast.

Antihyperglycemics can accumulate leading to hypoglycaemia and metformin can lead to lactic acidosis. Low molecular weight heparin and direct oral anticoagulants may accumulate in patients with impaired renal function, leading to risk of bleeding. In patients taking warfarin, an acute rise in urea may raise INR.