I was placed on Beta Blockers (Propranolol) just 6 weeks ago for thyrotoxicosis (overactive thyroid). The Class 2 has been suspended until my condition is stable under the drug regime - the nice lady at the CAA advied me that it had little or nothing to do with being on propranolol, rather that the condition itself was stable before I flew.
Apparantly large numbers of people take beta-blockers for a wide variety of reasons, uder both Class 2 and Class 1 medicals.