It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.
You should not use this medicine if you are also taking certain other medications such as carbamazepine (Tegretol®), phenobarbital (Luminal®), phenytoin (Dilantin®), rifabutin (Mycobutin®), rifampin (Rifadin®, Rimactane®), or St. John's Wort. Using these medicines together can cause serious problems. Make sure your doctor knows all of the medications you are taking.
Dizziness, lightheadedness, or fainting may occur, especially when you get up suddenly from a lying or sitting position. These symptoms are more likely to occur when you begin taking this medicine, or when the dose is increased.
This medicine may cause fluid retention (edema) in some patients. Tell your doctor right away if you have bloating or swelling of the face, arms, hands, lower legs, or feet; tingling of the hands or feet; or unusual weight gain or loss.
Do not stop taking this medicine without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are using before stopping completely.
Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine several days before having surgery or medical tests. This medicine may affect the results of certain medical tests.
Grapefruits and grapefruit juice may increase the effects of nifedipine by increasing the amount of this medicine in your body. You should not eat grapefruit or drink grapefruit juice while you taking this medicine.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.