Prostulax Drug Interactions

Interaction studies have only been performed in adults. No interactions have been seen when tamsulosin was given concomitantly with atenolol, enalapril, nifedipine or theophylline. Concomitant cimetidine brings about a rise in plasma levels of tamsulosin, whereas furosemide a fall, but as levels remain within the normal range posology need not be adjusted. In vitro, neither diazepam nor propranolol, trichlormethiazide, chlormadinone, amitriptyline, diclofenac, glibenclamide, simvastatin and warfarin change the free fraction of tamsulosin in human plasma. Neither does tamsulosin change the free fractions of diazepam, propranolol, trichlormethiazide and chlormadinone. Diclofenac and warfarin, however, may increase the elimination rate of tamsulosin. Concomitant administration of tamsulosin hydrochloride with strong inhibitors of CYP3A4 in patients with poor metabolizer CYP2D6 phenotype. Tamsulosin hydrochloride should be used with caution in combination with strong and moderate inhibitors of CYP3A4. Concomitant administration of tamsulosin hydrochloride with paroxetine, a strong inhibitor of CYP2D6, resulted in a Cmax, and AUC of tamsulosin that had increased by a factor of 1.3 and 1.6 respectively but these increases are not considered clinically relevant. Concurrent administration of other α1-adrenoceptor antagonist could lead to hypotensive effects.