Hello, I have had Asthma since I was 5 (Im now 35) , I was on Becatide, Ventolin, and sometimes steriods. My problem was when I was younger my mother did not always give me the preventers and just gave me the ventolin. This is very wrong.
In answer to your question. No seretide is not the last straw. your nurse should not have worried you needlessly like that.

I had a bad attack and the nurse reviewed my meds. she put me on Seretide and I am having a ball !! Before I took my ventolin about 6-7 times a day, but now I have it about 1-2 times, I even took a walk and forgot to lift it....

If seretide doesnt work there are many others, like Becloforte, Serevent,
Becetide, tablets called Singular and if you need a quick shot, Steriods,
( which I am on at the moment , for a Chest Infection) and Steriod injections, then of course there are Nebulisers, if your really bad , your doctor will always lend you a home nebuliser.

SO DONT DESPAIR, THERE IS A LOT MORE TO DO> maybe you should look into changing nurses.

Good luck and Breathe DEEP!!!!

Jo.