Is doxycycline effective in treatment of sinus infections?

Yes, doxycycline is often used to treat sinus infections, particularly those caused by bacteria such as Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Doxycycline belongs to a class of medications called tetracyclines, which have broad-spectrum antibiotic activity against a wide range of bacteria.

However, it's worth noting that not all sinus infections are caused by bacteria. Some sinus infections can be caused by viruses, in which case antibiotics like doxycycline would not be effective. The appropriate treatment for a sinus infection depends on the underlying cause, which is why it's important to consult a healthcare professional for proper diagnosis and management of sinus infections.