Drug Effects on the Glomerulus
Afferent arteriole (blood in) - prostaglandins normally dilate the afferent arteriole to maintain glomerular perfusion. NSAIDs block prostaglandin leading to constriction of the afferent arteriole and decreased perfusion.
Efferent arteriole (blood out) - when renal perfusion is low, angiotensin II causes constriction of efferent arteriole to maintain glomerular filtration. Therefore blocking angiotensin II can lead to acute fall in GFR if perfusion is low e.g. when used with a NSAID.
