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.

What is doxycycline?

Doxycycline is an antibiotic used to treat bacterial infections, eg, chest, sinus and pelvic infections. It may be chosen if you are allergic to penicillin. It 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 isn't effective against infections caused by viruses. 


In Aotearoa New Zealand, doxycycline is available as tablets (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 twice a day.  
  • Your doctor will advise you about 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 if the tablets are not swallowed properly. 
    • Remain upright for at least 30 minutes after taking doxycycline. Don't lie down for at least 30 minutes after taking doxycycline and don't take it just before bed.
    • Swallow the tablets whole – don't crush or chew them. 
  • Don't take your medicine together with dairy products. This is because dairy foods like milk, cheese and yoghurt can stop your body from absorbing doxycycline. You can have dairy products a few hours before or after your dose.
  • 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 don't take double the dose.

Things to consider while you are taking doxycycline

  • If you are taking the contraceptive pill, you don't usually need to use additional contraception if you're taking doxycycline. But if the antibiotic or the illness they're treating cause diarrhoea or vomiting lasting more than 24 hours, absorption of the contraceptive pill may be affected. If this happens, ask your doctor or pharmacist for advice about contraception over the following few days.
  • Taking some medicines (eg, antacids and iron preparations) at the same time as doxycycline can reduce how well it fights infection. Don't take indigestion remedies, iron or calcium preparations within 2 hours of taking doxycycline.
  • Doxycycline can make your skin more sensitive to the sun. This can cause a burning, tingling feeling on your skin when you are in the sun, or you may notice redness. When outside, protect your skin and eyes by using a good sunscreen (at least SPF30+) and wearing sunglasses, a sunhat and clothing that protects you from the sun.
  • If you are pregnant, think you might be pregnant or you're breastfeeding, let your doctor know before taking doxycycline.

Possible 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 these bother you.
  • Diarrhoea (loose, watery stools)
  • This may go away with time.
  • Tell your doctor if it bothers you.
  • 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
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product.

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

Additional resources for healthcare professionals

Doxine Medsafe, NZ
Drug-induced photosensitivity Medsafe, NZ, 2016
Emerging issues in the management of chlamydia and gonorrhoea BPAC, NZ, 2019
Doxycycline – safe prescribing – don't get burnt SafeRx, NZ, 2020

Credits: Sandra Ponen, Pharmacist. Reviewed By: Angela Lambie, Pharmacist, Auckland Last reviewed: 14 Oct 2022