The risk of first-dose hypotension with prazosin (resulting in dizziness or even fainting) is higher if the patient is already taking a beta blocker. This is likely to be true of other alpha blockers, particularly alfuzosin
, bunazosin and terazosin
. In a small study tamsulosin did not have any clinically relevant effects on blood pressure that was already well controlled by atenolol
. Alpha blockers
and beta blockers
may be combined for additional lowering of blood pressure in patients with hypertension.
It is recommended that those already taking beta blockers
should have the dose reduced to a maintenance dose and begin with a low-dose of an alpha blocker, with the first dose taken just before going to bed. They should also be warned about the possibility of postural hypotension and how to manage it (i.e. lay down, raise the legs, and get up slowly when recovered). Similarly, when adding a beta blocker to an alpha blocker, it may be prudent to decrease the dose of the alpha blocker and re-titrate as necessary to achieve adequate blood pressure control