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Oral tetracycline antibiotic (anti-acne / anti-rosacea)

Doxycycline 100mg (Acne / Rosacea)

Brand names: Efracea (40mg MR — rosacea), Vibramycin-D, Doxycycline (generic)

Used in: Pneumonia COPD

Doxycycline is a tetracycline antibiotic used for respiratory and atypical/zoonotic infections, malaria prophylaxis, and at lower doses for inflammatory acne and rosacea.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

DOSAGE AND ADMINISTRATION The usual dosage and frequency of administration of doxycycline differs from that of the other tetracyclines. Exceeding the recommended dosage may result in an increased incidence of side effects. Adults: The usual dose of oral doxycycline is 200 mg on the first day of treatment (administered 100 mg every 12 hours) followed by a maintenance dose of 100 mg/day. In the management of more severe infections (particularly chronic infections of the urinary tract), 100 mg every 12 hours is recommended. Pediatric Patients: For all pediatric patients weighing less than 45 kg with severe or life-threatening infections (e.g., anthrax, Rocky Mountain spotted fever), the …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2026-05-01. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

It inhibits bacterial protein synthesis at the 30S ribosomal subunit (bacteriostatic); in acne it also has anti-inflammatory effects.

Prescribing in practice

  • Avoid in pregnancy and in children under 12 (dental staining and effects on developing bone).
  • It causes photosensitivity (advise sun protection) and oesophageal irritation — take it with plenty of water and stay upright.
  • Absorption is reduced by calcium, iron, antacids and dairy — separate their timing.

Monitoring

Short courses need no routine monitoring; for longer acne courses review response and adverse effects.

Counselling the patient

  • Take it with a full glass of water and stay upright; not just before lying down.
  • Use sun protection, as you may burn more easily.
  • Separate it from milk, antacids and iron supplements.

Evidence & guidelines

Used for respiratory and atypical infections and as an option for inflammatory acne/rosacea per NICE/PHE guidance.

Reference: NICE CG184 Acne Vulgaris; BAD Acne Guidelines 2021; BAD Rosacea Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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