Yes you can. Hypertension treatment is something that has to be organised with your G.P and the C.A.A medical branch (probably through your A.M.E ) Normally there is a period when you cannot fly when initiating treatment or changing medication however providing the treatment is effective and there are no adverse side effects flying duties can usually be resumed with no restriction.
Not only beta blockers but ACE inhibitors and calcium channel blockers may be approved either individually or in combination. The treatment needs liason between the consultant and the aviation medicine specialist to ensure it is suitable in your case.
Hypertension is largely asymptomatic and is often referred to as a "silent killer". It affects many people and the good news is it is often easy to treat, and effective treatment will ensure you keep your medical certificate. Untreated you will run the risk of serious problems including sudden death ! Incidentally this latter result would cause you to lose your medical !
