Is 50 mg of metoprolol succ in the morning and 25 mg metoprolol succ at night - total of 75 a day too much for a 120 lb female for treatment of tachycardia from hyperthyroidism?

How to judge: If the dosing controls your tachycardia, and does not cause intolerable side effects, then your regimen is appropriately successful. But get additional confirmation from the doctor who knows you best!

Metoprolol: Definite signs of dosage excess with metoprolol would be heart rate under 55 or 60 or failure of rate to temporarily increase when necessary during physical activities or low blood pressure(under 100 systolic) causing lightheadedness or symptom of excessive fatigue. Ideally control of hyperthyroidism should prevent episodes of tachycardia. Some people tolerate 100mgs twice a day & others only 25/d