Interaction of antihypertensive acetazolamide with nonsteroidal anti-inflammatory drugs

The binding of antihypertensive acetazolamide with eleven nonsteroidal anti-inflammatory drugs (NSAIDs) was investigated at pH 3, 7 and 9.5 with the objective of monitoring their interactive pharmacokinetics during digestion and absorption in human body. The results of UV–Vis spectroscopy and cyclic voltammetry revealed two NSAIDs (acetaminophen and dichlofenic sodium) to interact with acetazolamide in stomach fluid conditions forming complexes of 1:1 and 1:2 stoichiometry. The complexation ratio was also verified by computational methods. The strong binding propensity of acetaminophen and dichlofenic sodium with acetazolamide prohibited their combined therapy. However, the poor binding affinity of aspirin and mefinamic acid suggested these drugs as preferred NSAIDs to be prescribed with acetazolamide.