What is doxycycline?

Doxycycline is an antibiotic medicine that belongs to a class of antibiotics known as tetracyclines.

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How does doxycycline work?

Doxycycline works by stopping the growth of bacteria. In acne, it reduces the number of bacteria on the skin's surface, and it has an anti-inflammatory action.

Doxycycline also works against parasites that cause malaria.

What is doxycycline used for?

Doxycycline is an antibiotic used to treat and prevent certain infections.

Your doctor may prescribe doxycycline to:

• treat respiratory tract infections such as pneumonia or bronchitis
• treat other infections such as prostatitis and chlamydia
• prevent risk of STI transmission in gay, bisexual and other men who have sex with men
• control acne
• prevent malaria (for people travelling in high-risk areas) or treat malaria infection
• treat anthrax infection or after anthrax exposure

Your doctor may have prescribed doxycycline for another reason. If you are unsure why you are taking doxycycline, ask your doctor.

It is important to always take doxycycline as prescribed by your doctor, even if you feel better. This will ensure your infection is treated completely. This also prevents antibiotic resistance (when the bacteria no longer respond to the antibiotic, and the antibiotic becomes less effective).

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What forms of doxycycline are available?

Doxycycline is the name of the active ingredient. It is available in many different brands, which have different:

• names
• appearances (size, shape or colour)
• forms (tablets and capsules)
• packaging

No matter which brand you are prescribed, doxycycline works in the same way to fight the infection.

In Australia, you can only get doxycycline with a doctor's prescription.

What are the possible side effects or risks of doxycycline?

All medicines have benefits, and they also have the risk of side effects. If you have any concerns speak to your doctor.

The more common side effects of doxycycline include:

• diarrhoea or vomiting
• oral or vaginal thrush
• rash or itching
• changes to the appearance of your nails
• irritation of the oesophagus (food pipe)
• loss of sense of taste
• ringing or other persistent noise in the ears

Doxycycline can also make your skin more sensitive. It is important to practice sun safety when using doxycycline as your risk of sunburn increases.

Serious side effects are rare but may need urgent medical attention. They include:

• headache, blurred vision, vomiting
• severe blisters and bleeding in the lips, eyes, mouth, nose and genitals
• severe skin reactions
• severe muscle pain
• difficulty or pain when swallowing
• dizziness
• fast heart rate

Although it is rare, some people can have an allergic reaction to doxycycline. If you've ever had allergies to any antibiotics in the past, especially to those in the tetracycline class, be sure to tell your doctor.

An allergic reaction may include:

• hives (raised, red and itchy rash)
• breathing problems
• swollen lips, tongue or face

This is not a full list of side effects. For more information about the side effects of doxycycline, read Consumer Medicine Information (CMI) for the brand of doxycycline prescribed, or speak to your doctor or pharmacist.

What should I be careful of when taking doxycycline?

Doxycycline can make your skin more sensitive to sunlight or UV light, increasing your risk of sunburn. If you are taking doxycycline, it's especially important to make sure you protect exposed skin with:

• at least SPF30+ sunscreen
• long clothing
• a hat

Doxycycline can stain teeth and affect how teeth enamel forms, and should not be taken by children under the age of 8 years. It should also not be taken if you are more than 16 weeks pregnant (when the baby's teeth are developing).

Doxycycline may reduce the effectiveness of some oral contraceptive pills. If you are taking oral contraceptive pills, ask your doctor if you need to use another form of contraception while you take doxycycline. This can be in addition to your current contraception.

How do I take doxycycline?

Take doxycycline with food or immediately after eating to minimise the chance of side effects.

Try to remain upright (by sitting up or standing) for at least 30 minutes after taking the medicine. This reduces your chance of developing irritation of the oesophagus (oesophagitis).

If you take antacids or supplements such as iron, calcium, zinc or magnesium, be careful with timing. Take them at least 2 hours before or after taking doxycycline, so your body can absorb the medicine properly.

Don't stop taking doxycycline until your doctor tells you that it's OK to do so.

Try to take doxycycline at the same time every day.

What if I forget or miss a dose?

If you forget or miss your dose, here's what you do:

• If this is close to the usual time — take it once you remember and then keep taking it at the usual times.
• If this is close to when you take the next dose — take your next dose at the time you planned and continue as normal. Do not take a double dose.

Speak to your doctor or pharmacist if you are not sure what to do.

When should I speak to my doctor?

Speak to your doctor if you:

• have side effects that trouble you
• have signs of an allergic reaction
• have a health condition or are taking medicine that may affect how your body reacts to doxycycline

Doxycycline is not recommended if you are more than 18 weeks pregnant. Let your doctor know if you:

• become pregnant
• are planning a pregnancy
• start breastfeeding

See the CMI for full details about when to speak with your doctor before or after you have started taking doxycycline. You can also discuss your concerns with your pharmacist.

If you take doxycycline for a few days and your symptoms worsen or do not improve, talk to your doctor.

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Resources and support

Asking about your treatment or medicine is important to help you understand your options. Read our guide to important questions to ask your pharmacist or doctor before taking a medicine.

You can also visit healthdirect's list of medicines that contain doxycycline to read the CMI for the brand of doxycycline prescribed.

Do you prefer to read in languages other than English?

You can find translated information about medicines on the NPS MedicineWise website.

Looking for information for Aboriginal and/or Torres Strait Islander people?

The National Aboriginal Community Controlled Health Organisation website has resources on medicines, side effects and more.