Doxycycline

Doxycycline is taken by mouth, as a capsule or tablet.

Typical adult dose for sinusitis:

• 200 mg on the first day, followed by
• 100 mg once daily for 4 more days (total 5-day course)

Some clinicians may prescribe 100 mg twice daily for 5 to 7 days depending on local guidance and clinical judgment.

Usage instructions:

• Take with a full glass of water while sitting or standing upright
• Take with food if it causes stomach upset, but avoid dairy close to the time of dosing
• Do not lie down for at least 30 minutes after taking
• Avoid taking iron, calcium, or antacid supplements at the same time, as they may reduce absorption
• Complete the full course, even if symptoms improve earlier

• Do not use in pregnancy or in children under 12, due to risk of tooth discolouration and effects on bone growth
• Use with caution in:
• People with liver disease
• Those taking photosensitising medications or with a history of sun sensitivity
• Avoid excessive sunlight or sunbeds during treatment, as doxycycline increases sun sensitivity

Yes. Doxycycline is generally safe and effective when used as directed. It is suitable for adults and children over 12 years, especially those who are penicillin-allergic.

It is often preferred for its once-daily dosing and broad spectrum of activity.

Common side effects include:

• Nausea
• Diarrhoea
• Abdominal pain
• Headache
• Increased sensitivity to sunlight (photosensitivity)

Less common but serious effects:

• Oesophageal irritation or ulceration (if not taken with water or if lying down after dose)
• Allergic reactions (rash, itching, swelling)
• Intracranial hypertension (very rare)

Seek medical attention if you experience severe headache, visual changes, difficulty swallowing, or signs of an allergic reaction.