No abstract

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to attenuate the hypotensive actions of various antihypertensive agents. This experimental study in dogs was undertaken to find out whether NSAIDs modified the pharmacological actions of an antihypertensive drug, guanfacine. Indometacin and enphenamic acid significantly prolonged the initial hypertensive response and blunted the subsequent hypotension produced by intravenous guanfacine. Ibuprofen and acetyl salicyclic acid also interacted in a similar manner, but to a lesser extent. Phenylbutazone, on the other hand, caused a blunting of the pressor response and potentiated the hypotension following guanfacine. When indometacin was given intracerebroventricularly, there was no interaction. These results suggest the necessity of monitoring hypertensive subjects taking guanfacine when NSAIDs are co-administered.