NSAIDs in patients taking lithium or with heart failure can cause which effect?

NSAIDs in patients taking lithium or with heart failure can cause which effect?

• A. Decrease renal blood flow
• B. Increase renal blood flow
• C. Increase urine output
• D. Improve cardiac function

Answer: (A)

NSAIDs block prostaglandin synthesis. In the kidneys, prostaglandins help dilate the afferent arteriole to maintain glomerular filtration when renal perfusion is low, such as in heart failure or reduced circulating volume. By inhibiting prostaglandins, NSAIDs cause afferent arteriolar constriction, reducing renal blood flow and GFR. This is why the effect described is a decrease in renal blood flow. They do not increase renal blood flow, nor do they improve urine output or cardiac function; in fact they can worsen renal function and fluid retention in heart failure and can raise lithium levels by reducing clearance.

NSAIDs block prostaglandin synthesis. In the kidneys, prostaglandins help dilate the afferent arteriole to maintain glomerular filtration when renal perfusion is low, such as in heart failure or reduced circulating volume. By inhibiting prostaglandins, NSAIDs cause afferent arteriolar constriction, reducing renal blood flow and GFR. This is why the effect described is a decrease in renal blood flow. They do not increase renal blood flow, nor do they improve urine output or cardiac function; in fact they can worsen renal function and fluid retention in heart failure and can raise lithium levels by reducing clearance.