Doxycycline

Infections

Also known as Vibramycin

Doxycycline is a tetracycline antibiotic used for acne, chest infections, tick-borne illnesses like Lyme disease, and certain sexually transmitted infections. It has two quirks worth knowing: it can badly burn your food pipe if a pill gets stuck, and it makes your skin far more sensitive to the sun. Handle those two things and it's a very useful drug. It won't work on viruses like colds or the flu.

How to take it

When

Take it with a full glass of water and stay upright for at least 30 minutes — don't take it right before bed.

Food

Food can ease nausea, but keep dairy, calcium, iron, and antacids a couple of hours away from each dose — they block the drug.

Avoid

Serious sunburns happen fast on this drug. Cover up and use sunscreen, even on cloudy days.

Good to know

Not for use in pregnancy or in young children — it can permanently stain developing teeth.

Missed a dose?

Take it as soon as you remember, with water, and stay upright afterward. If it's almost time for your next dose, skip the missed one. Never take a double dose.

Common side effects

Nausea or upset stomach
Sunburn much more easily
Diarrhea
Yeast infections

Call a doctor if

Trouble breathing, swelling of the face or throat, or hives — this can be a serious allergic reaction. Get emergency help now.
Pain or burning when you swallow, or chest pain after a dose — the pill may have injured your food pipe. Call your doctor.
Severe watery or bloody diarrhea, during treatment or even weeks after — this can be a serious gut infection (C. diff). Call your doctor; don't just take anti-diarrhea medicine.
A severe headache with blurred or double vision — rarely, this drug raises pressure around the brain. Call your doctor right away.

Educational only. This summary is drawn from public FDA labeling and MedlinePlus and simplified for readability. Your prescription label and your pharmacist always come first — doses and instructions vary from person to person.