Local companies blocking Norvasc monopolistic sales.

Pfizer Korea has monopolized Norvasc (amlodipine besylate), an antihypertensive drug on the market with annual sales of about 120 billion won last year, which seems to be curbed by local competitors, Hanmi, CJ and CKD, infiltrating the market with similar "me-too" products soon.

3 local companies successfully developed amlodipine derivatives (amlodipine camsylate and amlodipine maleate) by...