Doxycycline is one of the most commonly prescribed antibiotics in Australia. It belongs to the tetracycline family of antibiotics and is used to treat a wide range of bacterial infections, including sexually transmitted infections (STIs) such as chlamydia, skin conditions like acne, respiratory infections, and certain tick-borne diseases.

If you have been prescribed doxycycline or are wondering whether it may be suitable for your condition, this guide explains how it works, what it treats, potential side effects, and how you may be able to obtain a prescription through telehealth.

What Is Doxycycline?

Doxycycline is a broad-spectrum antibiotic that works by preventing bacteria from producing proteins they need to grow and multiply. Rather than killing bacteria immediately, it stops them from reproducing, allowing your immune system to clear the infection.

Because it works against many different bacteria, doxycycline has become one of the most versatile antibiotics used in general practice.

What Is Doxycycline Used For?

Doxycycline is commonly prescribed for:

• Chlamydia
• Acne vulgaris
• Rosacea
• Pelvic inflammatory disease (PID)
• Mycoplasma genitalium (in combination with other antibiotics)
• Community-acquired pneumonia
• Atypical respiratory infections
• Lyme disease (where applicable)
• Tick-borne infections
• Q fever
• Certain skin and soft tissue infections
• Malaria prevention for travellers to some destinations

Your doctor will determine whether doxycycline is the most appropriate antibiotic based on your symptoms, medical history and the suspected bacteria causing the infection.

Doxycycline for Chlamydia

One of the most common reasons doxycycline is prescribed is chlamydia, one of Australia's most frequently diagnosed sexually transmitted infections.

Many people with chlamydia have no symptoms, meaning they can unknowingly transmit the infection to sexual partners.

When symptoms occur they may include:

• Pain when urinating
• Unusual genital discharge
• Pelvic pain
• Pain during intercourse
• Testicular pain or swelling
• Rectal pain or discharge

Current Australian STI guidelines recommend doxycycline as the first-line treatment for uncomplicated genital and pharyngeal chlamydia in most non-pregnant adults.

It is important to:

• Complete the entire antibiotic course
• Avoid sexual contact until advised by your doctor
• Ensure recent sexual partners are tested and treated
• Consider repeat testing approximately three months after treatment due to the risk of reinfection

Doxycycline as Post-Exposure Prophylaxis (Doxy-PEP)

In addition to treating bacterial infections, doxycycline is also being used in selected high-risk individuals as doxycycline post-exposure prophylaxis (Doxy-PEP) to reduce the risk of certain sexually transmitted infections (STIs). Doxy-PEP involves taking a single dose of doxycycline as soon as possible, and within 72 hours after condomless sexual contact, following assessment by a healthcare professional. Clinical studies have shown that Doxy-PEP can significantly reduce the risk of chlamydia and syphilis, and may also lower the risk of gonorrhoea, although effectiveness against gonorrhoea varies because of increasing antibiotic resistance. Doxy-PEP is not recommended for everyone and should only be considered for people at higher risk of recurrent bacterial STIs as part of a comprehensive sexual health plan that includes regular STI screening, HIV prevention where appropriate, and safer sex practices. If clinically appropriate, a NextClinic doctor can assess whether Doxy-PEP is suitable for you during an online consultation.

Doxycycline for Acne

Doxycycline is also widely prescribed for moderate to severe inflammatory acne.

Unlike treating infections, doxycycline helps acne by:

• Reducing acne-causing bacteria
• Decreasing inflammation
• Reducing redness and swelling
• Preventing new inflammatory lesions

Doctors often prescribe doxycycline together with:

• Benzoyl peroxide
• Topical retinoids
• Azelaic acid

Treatment usually lasts several weeks to a few months and should be reviewed regularly to minimise antibiotic resistance.

Other Conditions Treated with Doxycycline

Besides STIs and acne, doxycycline may be prescribed for several other bacterial infections.

Respiratory infections

Doctors sometimes prescribe doxycycline for:

• Atypical pneumonia
• Sinus infections caused by susceptible bacteria
• Chest infections
• Bronchitis in selected cases

Not all respiratory infections require antibiotics because many are caused by viruses.

Skin infections

Doxycycline may be used for certain bacterial skin infections, including:

• Infected wounds
• Cellulitis caused by susceptible bacteria
• Rosacea
• Some animal bites

Tick-borne Diseases

Doxycycline is commonly used to treat several infections spread by ticks, including:

• Lyme disease (where present)
• Queensland tick typhus
• Scrub typhus
• Other rickettsial infections

Early treatment significantly improves outcomes.

Malaria Prevention

Travellers visiting malaria-risk regions may be prescribed doxycycline to reduce the risk of malaria infection.

It is usually started before travel, continued throughout the trip and for several weeks after leaving the malaria-endemic area.

How Do You Take Doxycycline?

To reduce side effects:

• Take it with a full glass of water.
• Remain upright for at least 30 minutes afterwards.
• Avoid taking it immediately before going to bed.
• Follow your doctor's instructions regarding food.
• Complete the full course even if you feel better.

Taking doxycycline incorrectly can increase the risk of irritation or ulceration of the oesophagus.

Common Side Effects of Doxycycline

Like all antibiotics, doxycycline may cause side effects.

The most common include:

• Nausea
• Upset stomach
• Diarrhoea
• Increased sensitivity to sunlight
• Headache
• Vaginal thrush

Sun sensitivity is particularly important. Wearing sunscreen, protective clothing and avoiding prolonged sun exposure can help reduce the risk of severe sunburn.

Seek medical attention immediately if you develop:

• Difficulty breathing
• Swelling of the face or throat
• Severe allergic rash
• Persistent severe diarrhoea
• Vision changes or severe headache

Who Should Not Take Doxycycline?

Doxycycline may not be suitable for everyone.

Tell your doctor if you:

• Are pregnant or planning pregnancy
• Are breastfeeding
• Have liver disease
• Have difficulty swallowing
• Have previously had an allergic reaction to tetracycline antibiotics
• Take medications that may interact with doxycycline

Your doctor will determine whether another antibiotic would be more appropriate.

Can I Drink Alcohol While Taking Doxycycline?

Small amounts of alcohol do not usually interfere with doxycycline.

However, heavy or chronic alcohol consumption may reduce its effectiveness and can increase the risk of dehydration or stomach irritation.

Can I Get a Doxycycline Prescription Online?

Yes. If clinically appropriate, an Australian-registered doctor can assess your condition via telehealth and prescribe doxycycline where suitable.

Conditions that may be assessed online include:

• Chlamydia
• Acne
• Rosacea
• Some bacterial skin infections
• Selected respiratory infections

Not every condition is suitable for telehealth, and antibiotics are only prescribed when clinically indicated after an appropriate medical assessment.

Doxycycline and Antibiotic Resistance

Antibiotic resistance is a growing global health concern.

To help prevent resistance:

• Only take antibiotics when prescribed.
• Never share antibiotics.
• Finish the prescribed course.
• Do not use leftover antibiotics.
• Attend follow-up appointments if symptoms persist.

Responsible antibiotic prescribing helps preserve their effectiveness for future generations.

Disclaimer

This medical blog provides general information and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with your regular doctor for specific medical concerns. The content is based on the knowledge available at the time of publication and may change. While we strive for accuracy, we make no warranties regarding completeness or reliability. Use the information at your own risk. Links to other websites are provided for convenience and do not imply endorsement. The views expressed are those of the authors and not necessarily representative of any institutions.