I Have Been Using Asthalin For Last 12 Years, I

i have been using asthalin for last 12 years, i never had any attacks but whenever i exert, i mean running or wailking fast, getting exicited causes breathelessness , in had to take 4-5 pups a day,smoke and dust also causes the same symptoms in me, about a week back i changed to for air 250, that i have to take only once, rest of the day iam comfortable even in dust, my question is it safe to use that drug?