Key takeaways
Doxycycline monohydrate (Monodox, Oracea) and azithromycin (Zithromax) are both antibiotics, but they belong to different classes and treat infections differently. Doxycycline monohydrate is a tetracycline antibiotic that stops bacteria from making certain proteins, while azithromycin is a macrolide antibiotic that also prevents bacteria from making proteins but in a different way. Doxycycline monohydrate is used for a wide range of bacterial infections, including severe acne and rosacea, and must be taken twice daily for most infections. In contrast, azithromycin is often taken once daily for a shorter duration, typically 3 to 5 days, and is available in a convenient Z-Pak form. Doxycycline monohydrate can cause tooth discoloration in children under 8 and is not safe during pregnancy, whereas azithromycin is generally considered safe during pregnancy but can cause heart rhythm problems. Both medications can cause stomach-related side effects, but doxycycline monohydrate also makes your skin more sensitive to sunlight. Both are available as lower-cost generic form and come in both tablet and liquid forms.
