If you will be taking this medicine for a long time, it is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.
Do not take sildenafil (Viagra®), tadalafil (Cialis®), or vardenafil (Levitra®) while you are using this medicine. Using these medicines together may cause blurred vision, dizziness, lightheadedness, or fainting. If you are taking these medicines and you experience an angina attack, you must go to the hospital right away.
This medicine may cause headaches. These headaches are a sign that the medicine is working. Do not stop using the medicine or change the time you use it in order to avoid the headaches. If you have severe pain, talk with your doctor.
Dizziness, lightheadedness, or faintness may occur, especially when you get up quickly from a lying or sitting position. Getting up slowly may help.
Dizziness, lightheadedness, or fainting is also more likely to occur if you drink alcohol, stand for long periods of time, exercise, or if the weather is hot. While you are taking this medicine, be careful to limit the amount of alcohol you drink. Also, use extra care during exercise or hot weather or if you must stand for long periods of time.
Do not stop using this medicine without checking first with your doctor. Your doctor may want you to gradually reduce the amount you are using before stopping it completely.