I have been taking Propanolol (AKA Inderal--a beta blocker) to control hepatic portal hypertension for about 4 1/2 years now. Along the way I discovered that it is an effective agent in managing performance anxiety.
At first it was difficult for me to adjust to the effects. It gave me too much of a feeling of playing with "ice water in my veins". But I have now become used to it, as I have to take the medicine twice a day.
Beta blockers block the receptors for norepinephrine (also known as noradrenaline)thus preventing the physical effects of a person's natural fight or flight response. They are not sedatives, and they can't help anxiety of a purely psychological nature.
The degree of the effects depends on the dosage and the individual's sensitivity to the medication. Peak effect occurs in one to one and a half hours. Ideally, this could allow a player to play at his or her best, without the distraction or interference of excessive fight or flight symptoms i.e. excessive sweating, tremors, nervousness.
Beta blockers will not help the emotional symptoms of performance anxiety (for example, sleep problems or negative inner voices).
Beta blockers should never be taken without a doctor's supervision and then only for legitimate medical needs. In spite of this, many pool, billiards, and snooker players use beta blockers w/o supervision. Other sports where the use of beta blockers is common are archery, and rifle / handgun/ shotgun competition. Beta blockers are also used quite frequently by musicians, comedians, and actors to prevent the negative effects of stage fright.
Beta blockers are on the list of banned substances in World Pool Association sanctioned competition.