Can I Take Amlodipine Instead Of Tenoric For BP?

I have been on Tenoric 25 (OD) for almost five years. Since last fortnight, my BP was 140/90 and my dose was doubled to Tenoric 25, twice a day. After a week of Tenoric 25 (BD), the BP still is unchanged around 140/90. Should I switch to Amlodipine 5 or Amlodipine 10? What should be the protocol to switch from Tenoric to Amlodipine? Please advise.