Hi, I Am 63 Years Old And In Good Health.

Hi, I am 63 years old and in good health. I have had a chronic cough now for 10-11 yrs. I've been diagnosed with asthma by 1 pulmonologist and 1 pulm. said I did not have asthma. I see an allergist/pulm now that says I definitely have asthma and I've tried many inhalers that don't work. I was tested for eosinophilic asthma and I had 300 in my blood so I was started on Nucala monthly injections about 10 months ago. They have helped a little. My Dr. then started me on Gabapentin 300mg TID and it reduced my cough for about a month then it got worse again. He increased dose to 400mg TID and it has helped but I have gained about 12 lbs. which I cannot get off. I'm wondering if there is another epilepsy medication I can take that won't make me gain weight. I Topamax used for chronic cough??