Hello, I Am A 73 Year Old Female Who Has

Hello, I am a 73 year old female who has an ongoing heart problem. My doctor wrote a prescription for Isoosorbide dinitrate 10 mg. I have read the side effects and many medications cause me to have breathing problems. My lungs are scarred from having pneumonia many times during my life and I also have asthma. I am afraid to try these for fear they will put me into a severe asthma attack.