Health - Rivotril/Clonazepam 2mg 30?? for panic attacks?

[miss_fliss]

Hi,
SWIM has been getting severe panic attacks for several weeks, the Dr. has prescribed SWIM 20mg Beta Blockers three times a day, which help the physical symptoms but don't stop a panic attack once it starts.
SWIM's just bought some Clonazepam from a friend, who says they are 30mg. SWIM's friend says just take one or two. The packet says "Rivotril Tablets 2mg Clonazepam". SWIM's friend takes them for epilepsy, and has also taken Valium for a long time for epilepsy.
SWIM is wondering
1) Whether it is ok to take the Clonazepam if a panic attack starts, whilst also taking the Beta Blockers? And
2) The dosage, how many should SWIM take? As, if her friend has been taking other benzodiazepines (i.e.Valium) for so long, SWIM assumes she will have built up tolerance, and SWIM has never taken any benzo's before so won't have any tolerance, and doesn't want to knock herself out.
Thank you!