The most common side effects of generic Periostat medication are nausea and diarrhea, but these effects are usually temporary. More severe, though less common side effects can include jaundice, persistent sore throat or fever, unusual bleeding or bruising, or the emergence of white patches in the mouth. Few people are allergic to this antibiotic, but patients should watch for symptoms of an allergic reaction such as rash, swelling, dizziness, and trouble breathing. Tetracycline-based antibiotics, like doxycycline, also frequently make patients noticeably more susceptible to sunburn, so precautions should be taken to avoid this if prolonged exposure to sunlight or other ultraviolet light is anticipated.