Different drugs. Ptu (propylthiouracil) is a drug used to block the thyroid from making thyroid hormones in patients primarily with grave's disease. It has potential serious toxicities involving both liver and bone marrow. Methimazole may be safer, though also has toxicities. Blood work is monitored closely. Beta blockers are medications which help counter side effects of hyperthyroidism like high bp, rapid heart rate, nervousness.