Is sulfonamide group of tamsulosin main factor in the pathophysiology of floppy iris syndrome?

Abstract

Intraoperative floppy iris syndrome (IFIS) was first described by Chang et al. in 2005 in using α-blockers. Tamsulosin a selective α-(a) adrenergic receptor (AR) antagonist is a commonly prescribed drug for benign hyperplasia of the prostate (BPH), and it has been shown to have the strongest association with IFIS. Other drugs that predispose to IFIS include alfuzosin, doxazosin, terazosin, finasteride, labetalol, mianserin, chlorpromazine, donepezil and other antipsychotic agents. In literature reviews, the pathophysiological evaluation of IFIS has not yielded clear results. In the present study, we examined this pathophysiological mechanism from a different perspective and somewhat hypothetically analyzed the chemical composition of these drugs. We analyzed their chemical formulas and pharmacological effects in combination. We compared tamsulosin with other IFIS-inducing α-blockers and propose that its sulfonamide group might be a causative factor.