It really depends on the medication. If you stop a
diuretic nothing will happen very quickly, though you may gradually resume being hypertensive. Other medications, however, such as beta blockers, can have quite dramatic effects if stopped abruptly. In people with coronary vessel disease as well as
hypertension, abruptly stopping beta blockers, as well as some others can precipitate
chest pain (angina) and more rarely actual heart damage (
myocardial infarction).
Listen, if you don't like the side effects of your medication, talk to your doctor. There are SO many different medications available to treat hypertension, that you can almost always find medications that you can live with.
Don't just stop your medication. Be smart, take care of yourself and don't ignore your blood pressure
Remember, one of the biggest reasons that hypertension is so dangerous is that you don't really have symptoms until really bad things have started to happen. (
Kidney failure, strokes, heart complications such as failure and heart attacks)
Call your doctor, and let him (or her) help you get on the medication you need.
Best of luck