Sounds like 'dox-i-sye- kleen'

Doxycycline is an antibiotic used to treat different infections caused by bacteria. Find out how to take it safely and possible side effects. Doxycycline is also called Doxine.

Type of medicine Also called
  • Antibiotic (to treat infections)
  • Tetracycline antibiotic
  • Doxine
  • Doxy
  • Doxylin

What is doxycycline?

Doxycycline is an antibiotic used to treat bacterial infections, such as of the chest, sinus, eye and pelvic infections. It may be chosen if you are allergic to penicillins. Doxycycline is also used to treat skin conditions such as acne and for malaria prevention when travelling to some countries.

Doxycycline belongs to a group of antibiotics called tetracyclines. Like all antibiotics, doxycycline is not effective against infections caused by viruses. In New Zealand, doxycycline is available as tablets (50 mg and 100 mg).


  • The dose of doxycycline will be different for different people depending on the type of infection. 
  • The usual dose of doxycycline is 100 mg once or two times a day.  
  • Your doctor will advise you how long to take doxycycline for.
  • Always take your doxycycline exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much to take, how often to take it, and any special instructions.
  • Note: doxycycline is not usually given to children because it can affect growing teeth and bones.

How to take doxycycline

  • Swallow your doxycycline tablets with a large glass of water.
    • Take doxycycline with food and a large glass of water to wash them down. Doxycycline can cause severe indigestion and problems with your throat and oesophagus (gut) if the tablets are not swallowed properly. 
    • Remain upright for at least 30 minutes after taking doxycycline. Do not lie down for at least 30 minutes after taking doxycycline or do not take it just before bed.
    • Swallow the tablets whole – do not crush or chew them. 
  • Missed dose
    • If you forget to take your dose, take it as soon as you remember. But, if it is nearly time for your next dose, just take it at the right time; do not take double the dose.

It is important to take the whole course of antibiotics for the number of days your doctor has told you to. Do not stop taking it, even if you feel your infection has cleared up. Talk to your doctor first.

Precautions – while taking doxycycline 

Sun protection

Doxycycline can make your skin more sensitive to the sun. You can get a burning, tingling feeling on your skin when you are in the sun, or you may notice a darker tan, or redness. When outside, protect your skin and eyes by using a good sunscreen (at least SPF30+). a sunhat and clothing that protects you from the sun, and wearing sunglasses.

Taking other medicines

Taking some medicines such as antacids and iron preparations at the same time as doxcycline can reduce its effect in fighting infection. Do not take indigestion remedies, iron or calcium preparations within 2 hours of taking doxycycline.

Precautions – before starting doxycycline

  • Are you pregnant, planning a pregnancy or breastfeeding?
  • Do you have liver or kidney problems?
  • Do you have lupus or myasthenia gravis?
  • Are taking any other medicines? This includes any medicines you are taking which you can buy without a prescription, as well as herbal and complementary medicines.

If so, it’s important that you tell your doctor or pharmacist before you start doxycycline. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care.

Side effects

Like all medicines, doxycycline can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Nausea (feeling sick) or vomiting
  • Tummy upset
  • Indigestion
  • Take doxycycline with or straight after food.
  • Tell your doctor if troublesome.
  • Diarrhoea (loose, watery stools)
  • This may go away with time.
  • Tell your doctor if troublesome.
  • Vaginal itching, soreness or discharge (thrush)
  • Tell your doctor or pharmacist.
  • Painful throat or stomach or trouble swallowing
  • Tell your doctor immediately or ring HealthLine 0800 611 116
  • Headache or problems with your eyesight
  • Tell your doctor immediately or ring HealthLine 0800 611 116
  • Allergic reaction such as skin rash, itching, swelling of the lips, face, and mouth or difficulty breathing
  • Tell your doctor immediately or ring HealthLine 0800 611 116


Doxycycline interacts with some medicines and herbal supplements, so check with your doctor or pharmacist before starting doxycycline.

Learn more

Medsafe Consumer Information Sheet: Doxine 
New Zealand Formulary Patient Information: Doxycycline


  1. Doxycycline New Zealand Formulary
  2. Antibiotics: choices for common infections BPAC, 2017
Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 01 Feb 2019