Toprol acts by slowing the heart rate and widening the blood vessels. In general, there are no contraindications to using Toprol with an antibiotic. I would suggest that in the future these questions regarding medicine interactions be addressed to the physician who prescribed the medication. Sinus infections are a bear to treat. They become encapsulated in nooks and crannies and biofilms. In addition they may be due to different bacteria. Doxycline is a tetracycline and many bacteria will not respond to such treatment. The ideas situation is to obtain a culture. Irrigation with warm sterile saline injected with a small bulb syringe is the preferrered treatment, several times a day, head back, first in the left nostril and then the right. "Sniffing" the saline will not do the job. You can make your own saline with boiled water and salt.
try see salt one spoon in a glass of wotm water and snif it on one side of u nose putting pressure on the other side then switch,