 [ Symptoms ] i started taking doxycycline last week for acne and it caused me to menstruate why is that happening [ Disease ] medicines used to treat angina reduce the heart muscle is demand for oxygen to compensate for the reduced blood supply three commonly used classes of drugs are the nitrates beta blockers and calcium blockers nitroglycerin nitro bid is an example of a nitrate examples of beta blockers include propranolol inderal and atenolol tenormin examples of calcium blockers include nicardipine cardene and nifedipine procardia adalat unstable angina is also treated with aspirin and the intravenous blood thinner heparin aspirin prevents clumping of platelets while heparin prevents blood clotting on the surface of plaques in a critically narrowed artery when patients continue to have angina despite taking maximum medications or when significant ischemia still occurs with exercise testing they usually need coronary arteriography during coronary arteriography doctors decide whether the patient should be considered for percutaneous coronary intervention or percutaneous transluminal angioplasty ptca where a small balloon is used to inflate the blockage angioplasty ptca is usually followed by placement of a stent or coronary artery bypass graft surgery cabg to increase coronary artery blood flow angioplasty can produce excellent results in carefully selected patients under x ray guidance a wire is advanced from the groin to the coronary artery a small catheter with a balloon at the end is threaded over the wire to reach the narrowed segment the balloon is then inflated to push the artery open and a steel mesh stent is generally inserted cabg surgery is performed to relieve angina in patients who have failed medical therapy and are not good candidates for angioplasty ptca cabg surgery is ideal for patients with many narrowings in multiple coronary artery branches such as is often seen in patients with diabetes cabg surgery has been shown to improve long term survival in patients with significant narrowing of the left main coronary artery and in patients with significant narrowing of multiple arteries especially in those with decreased heart muscle pump function