Doxycycline 100 mg is a widely used antibiotic in Australia, prescribed for a variety of bacterial infections and preventive treatments. As a member of the tetracycline class, it is valued for its broad-spectrum activity, ease of use, and effectiveness. This blog post offers a clear and up-to-date overview of doxycycline 100 mg, including its common uses, dosing guidelines, and important considerations for Australians in 2025.
What Is Doxycycline 100 mg?
Doxycycline is an oral antibiotic that works by inhibiting bacterial protein synthesis, which stops bacteria from growing and multiplying. The 100 mg tablets are commonly prescribed for many infections and are available in both immediate-release and delayed-release forms.
Common Uses of Doxycycline 100 mg in Australia
Doxycycline 100 mg is prescribed for a wide range of conditions, including:
- Respiratory tract infections: Such as pneumonia, bronchitis, sinusitis, pharyngitis, and tonsillitis, especially those caused by atypical bacteria like Mycoplasma pneumoniae and Chlamydophila pneumoniae.
- Sexually transmitted infections (STIs): Including chlamydia and lymphogranuloma venereum, with doxycycline often used as first-line treatment.
- Skin conditions: Management of moderate to severe acne and rosacea, where its anti-inflammatory properties help reduce symptoms.
- Tick-borne and zoonotic infections: Such as Queensland tick typhus, scrub typhus, murine typhus, and Q fever, which are more prevalent in Australia’s environment.
- Malaria prevention: Used as chemoprophylaxis for travelers visiting malaria-endemic areas, starting 1-2 days before travel and continuing for 4 weeks after leaving the region.
- Other infections: Including psittacosis, brucellosis, cholera, and syphilis.
Dosage Guidelines for Adults
- For infections: The typical dosing starts with a loading dose of 200 mg on the first day (usually 100 mg twice daily), followed by 100 mg once or twice daily depending on the severity of the infection. For more serious infections, 100 mg twice daily is recommended.
- For malaria prophylaxis: 100 mg once daily, beginning 1 to 2 days before entering the malaria area and continuing for 4 weeks after leaving.
- For skin conditions: Lower doses such as 40 mg once daily or 20 mg twice daily may be prescribed for acne or rosacea.
It is important to take doxycycline with a full glass of water and remain upright for at least 30 minutes afterward to prevent irritation of the esophagus.
Important Considerations
- Side effects: Common side effects include nausea, diarrhea, and increased sensitivity to sunlight, so sun protection is essential.
- Drug interactions: Doxycycline absorption can be reduced by calcium, iron supplements, antacids, and some other medications, so doses should be spaced accordingly.
- Not recommended for young children: Generally avoided in children under 8 years unless benefits outweigh risks.
- Pregnancy and breastfeeding: Should be used cautiously and only if clearly needed.
- Complete the full course: Even if symptoms improve early, to prevent resistance and relapse.
How to Take Doxycycline 100 mg
Swallow tablets whole with plenty of water. Avoid lying down immediately after taking the medication to reduce the risk of throat irritation or esophagitis. If you miss a dose, take it as soon as you remember unless it is close to the next dose; never double up doses.
Doxycycline 100 mg remains a versatile and effective antibiotic widely used in Australia in 2025 for treating a variety of bacterial infections and preventing malaria. Proper adherence to dosing instructions and awareness of potential side effects will help ensure safe and successful treatment. Always consult your healthcare provider for personalized advice and before starting or stopping doxycycline.