Tetracycline-class antibiotics: what you need to know

Tetracyclines are a family of broad‑spectrum antibiotics many people recognize by names like doxycycline, minocycline, and plain tetracycline. They stop bacteria from making proteins so the bugs can’t grow. Doctors use them for a mix of infections — acne, certain respiratory infections, some sexually transmitted infections, and specific tick‑borne diseases. A stronger member, tigecycline, is reserved for serious hospital infections and is given by IV.

Common uses and dosing basics

Doxycycline is the most common choice in outpatient care. Typical adult dosing is 100 mg twice daily for many infections, but dosing and length vary by diagnosis. Minocycline often appears in acne treatment plans (usually 50–100 mg once or twice a day). Tetracycline itself is less used now because doxycycline works better and is easier on the stomach. Tigecycline is IV only and used when other drugs fail or for resistant hospital bugs.

Always follow the prescription. Some infections need a short 5–7 day course; acne or certain chronic conditions may need weeks. Stopping early can lead to relapse or resistance.

Safety, interactions, and practical tips

Key safety points: avoid tetracyclines during pregnancy and in children under 8 because they can permanently stain teeth and affect bone growth. If you’re pregnant or breastfeeding, tell your clinician — an alternative is usually chosen.

Side effects to expect: nausea, upset stomach, and photosensitivity (you burn more easily). Minocycline can sometimes cause dizziness or skin pigmentation changes over long use. Rare but serious problems include severe diarrhea (which could signal C. difficile), liver problems, or allergic reactions — seek medical help right away for high fever, yellowing skin, or breathing trouble.

Drug interactions matter. Don’t take tetracyclines with dairy products, calcium, iron, magnesium, or antacids — these bind the drug and make it less effective. Take the pill with a full glass of water and stay upright for 30 minutes to reduce throat or esophagus irritation. For doxycycline, taking with food can cut nausea but avoid high‑calcium meals right at dosing time.

Resistance is real. These drugs shouldn’t be used for viral illnesses like colds or most sore throats. Finish the full course unless your doctor tells you to stop, and avoid reusing leftover pills for a new illness.

Buying antibiotics online? Use only reputable pharmacies and a valid prescription. If an online seller offers antibiotics without asking for a prescription, that’s a red flag — fake or unsafe meds are common. When in doubt, ask your pharmacist or clinician.

If you have questions about a specific tetracycline (dose, side effects, or whether it’s right for you), mention your age, pregnancy status, and any other meds you take — that helps your clinician give safe, specific advice.