Doxycycline: What It Treats, How to Take It, and Practical Safety Tips

Doxycycline is a widely used antibiotic that treats many bacterial infections: acne, respiratory infections, Lyme disease, certain STIs like chlamydia, and it’s also used for malaria prevention. It comes as pills and an injectable form, and generic options make it affordable. Below are concrete, useful instructions you can use right away.

How to take doxycycline

Adults commonly take 100 mg twice daily or 200 mg once daily for many infections. For chlamydia the usual plan is 100 mg twice daily for seven days; early Lyme disease often uses 100 mg twice daily for 10–21 days. For malaria prevention start doxycycline 1–2 days before travel, take it daily while at risk, and continue for four weeks after leaving the area. Always follow the exact dose and length your prescriber gives you.

Take each dose with a full glass of water and remain upright for at least 30 minutes to avoid throat or esophagus irritation. You can take doxycycline with food to lower stomach upset. Don’t take it within two hours of dairy, calcium or iron supplements, antacids with aluminum or magnesium, or bismuth—these block absorption. If you need those, separate them by at least two to four hours.

Side effects, warnings, and interactions

Common side effects include nausea, mild diarrhea, and increased sensitivity to the sun. Wear sunscreen and protective clothing when outdoors. Severe diarrhea, blood in stools, allergic reactions, or trouble breathing are red flags—stop the drug and seek medical help immediately because these can signal serious problems like C. difficile infection or anaphylaxis.

Avoid doxycycline in pregnancy and in children under eight due to risks to teeth and bone development. If you’re breastfeeding, talk to your provider—small amounts pass into breast milk and a doctor will weigh risks and benefits. Doxycycline can interact with blood thinners (warfarin) and some other medications; always list all drugs and supplements to your prescriber.

There’s a rare risk of increased intracranial pressure when combined with certain medicines like isotretinoin—watch for new, severe headaches or vision changes and get checked fast.

Don’t stop early just because you feel better. Finishing the prescribed course reduces the chance of resistant bacteria. If you miss a dose, take it when you remember unless it’s almost time for your next dose—don’t double up. Store pills at room temperature away from moisture and heat.

Only buy doxycycline from licensed pharmacies and always use a prescription. Counterfeit or low-quality antibiotics can fail and be unsafe. If you’re unsure whether doxycycline is right for your infection, call your healthcare provider or a pharmacist—tell them your symptoms, other meds, and any allergies so they can advise you clearly.