If you have angina or high blood pressure, your healthcare provider may prescribe nifedipine. The drug comes in the form of tablets and capsules, and is typically taken one to four times a day. There are many different versions of nifedipine -- some are equivalent to each other, while others are not. Possible side effects include headaches, flushing, and dizziness. All nifedipine tablets are extended-release, while all nifedipine capsules are immediate-release.