Zithromax is a good drug but not a "great" drug for treating sinusitis
. Most likely you were partially treated and still have inflammation
in your sinuses which in turn is triggering your asthma
. A longer course of the medication like Augmentin
(amoxicillin and clavulanate
) possibly combined with a short course of low-dose Prednisone
would be potentially great benefit to you. I would strongly suggest you discuss this with your primary care doctor or that you seek a consultation with an ENT doctor.