Comparison of Vascular α1-Adrenoceptor Antagonism of Tamsulosin in Oral Controlled Absorption System (OCAS) and Modified Release (MR) Formulations

Tamsulosin OCAS 0.4 mg tablets show less cardiovascular α1-AR antagonism, i.e. less inhibition of vasoconstriction and total peripheral resistance, than tamsulosin MR 0.4 mg capsules following single dosing in fasting healthy volunteers. This is most likely related to reduced drug exposure by the OCAS formulation. The data indicate that on an empty stomach tamsulosin OCAS may provide a better cardiovascular safety profile than tamsulosin MR.