Balplayer:
Propranolol is a beta blocker. I don't know about beta blokcers use as far as passing a lie detector goes, but if they can indeed be used for that purpose, then propranolol should work just like the rest of them. In general, beta blockers share similar characteristic effects on the heart, they just differ in route of administration and/or duration of action. They will all selectively antagonize beta receptors. When that is done in cardiac tissue, the heart can't respond to things like epinephrine or norepinephrine, and therefore, can't increase in rate. I imagine that it would work for an anxiety producing situation such as a polygraph too. Hope that answers your question...
On a side note, don't take a non-selective beta blocker like propranolol if you have asthma, it could cause an attack. Talk with your doctor to find out if this treatment is right for you.
md2b