 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST] . In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.The precautions of Doxycycline Monohydrate Oral: See also Side Effects section. Before taking doxycycline, tell your doctor or pharmacist if you are allergic to it; or to other tetracyclines (such as minocycline); or if you have any other allergies. This product may contain inactive ingredients (such as sulfites, soy found in some brands), which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: trouble swallowing, esophagus problems (such as hiatal hernia or reflux/heartburn). Doxycycline may cause live bacterial vaccines (such as typhoid vaccine) to not work well. Tell your health care professional that you are using doxycycline before having any immunizations/vaccinations. </s>