I have lungs problem by birth that is pulmonary hypertension. My oxygen level in blood is only 78. I can't do any physical type work can't walk fast or run. Fatigue easily. I have to take oxygen daily minimum 2 or 3 hours at night. Doctor has advised assurans tablet. I am taking this tablet from last two years. I just want to confirm is this tablet has side effects. And please tell how I can increase my oxygen level and improve my condition.