Tetracycline: what it treats and how to use it safely

Tetracyclines are a family of antibiotics that includes tetracycline, doxycycline and minocycline. They treat a range of infections — acne, some respiratory infections, certain tick-borne illnesses (like Lyme), and sexually transmitted infections such as chlamydia. They work by stopping bacteria from making proteins they need to grow.

Before you take any tetracycline, ask: is this the right antibiotic for my infection? These drugs don’t work for viral illnesses like colds or flu. Always follow a prescriber’s advice and don’t use leftover antibiotics.

How to take tetracyclines

How you take them matters. Classic tetracycline should be taken on an empty stomach (one hour before or two hours after food) because dairy, antacids, iron, and calcium bind the drug and cut absorption. Doxycycline is better tolerated with food, but avoid taking it with milk or calcium at the same time if you want maximum effect.

Drink a full glass of water with each dose and stay upright for 30 minutes after taking doxycycline or minocycline. That reduces the chance of throat or esophagus irritation. Finish the full course even if you feel better, unless your doctor tells you otherwise.

Side effects, warnings, and drug interactions

Common side effects are nausea, diarrhea, and increased sun sensitivity — get sunburned more easily. Use sunscreen and avoid long sun exposure. A more important rule: tetracyclines can permanently stain teeth and affect bone growth, so they’re usually avoided in pregnant women and children under 8.

These drugs interact with antacids, iron supplements, calcium, and some multivitamins. Give at least 2–4 hours between those products and your antibiotic dose. Tell your prescriber about other medicines you're taking, including oral contraceptives and blood thinners, so they can check for interactions.

Serious reactions are rare but possible — severe diarrhea, allergic rash, high fever, or trouble breathing need prompt medical attention. If you develop yellowing teeth, dark urine, jaundice, or unusual muscle weakness, contact your doctor.

Antibiotic resistance is real. Use tetracyclines only when prescribed and only for the condition listed. If symptoms don’t improve in 48–72 hours, or if they get worse, go back to your healthcare provider — you may need a different test or a different medicine.

Looking for more on specific tetracycline drugs, dosing differences, or safer alternatives? Check articles on doxycycline vs. tetracycline, acne treatment options, and tips for traveling with antibiotics. Practical, simple steps — like taking your dose correctly and avoiding sun — cut side effects and help treatment work faster.