Is isoprenaline not different from alpha blocker as both don’t make action on alpha receptor?
Isoprenaline stimulates the beta receptors both directly and reflexly (2ry to its hypotensive effect). It has no effect on alpha receptors. It is very short acting. Alpha blockers stimulates the beta receptors reflexly only due to their hypotensive effect mediated by alpha receptors blockade. They are long acting.