[Effect of isosorbide dinitrate in relation to posture and age]

Rapid tilting into the 90 degrees upright position after 20 mg ISDN sublingually demonstrates a better orthostatic tolerance of the older group (in spite of a lower cardiac output) in comparison to the younger one. This can be explained by a higher tone of the resistance vessels and a stronger stretch resistance of the arteries of the elastic type (and probably of the veins), which are opposing the hydrostatic effects of orthostasis and guarantee a minor shifting of blood to the lower extremities. The increase of rigidity of the blood vessels with aging declares the better drug resistance of the older group but also points - on the other hand - to the borders of ISDN therapy.