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Tetracycline antibiotic

Doxycycline 100mg Capsules (Sinusitis — Penicillin Allergy)

Brand names: Vibramycin-D, Efracea (acne — different indication)

Used in: Pneumonia COPD Cellulitis & Skin Infection

Oral doxycycline, a tetracycline antibiotic, used here as an alternative agent for bacterial sinusitis in patients with penicillin allergy.

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.

Clinical monograph

How it works

It is a bacteriostatic tetracycline that binds the bacterial 30S ribosomal subunit and inhibits protein synthesis, covering common respiratory pathogens implicated in sinusitis.

Prescribing in practice

  • Contraindicated in pregnancy, breastfeeding and in children because tetracyclines deposit in growing bone and teeth, causing permanent discolouration and enamel defects.
  • It can cause photosensitivity and oesophageal irritation or ulceration, so it should be taken with plenty of fluid and the patient kept upright after dosing.
  • Absorption is reduced by calcium, iron, magnesium and antacids, which should be separated in time from the dose.

Monitoring

Routine laboratory monitoring is not generally required for a short sinusitis course; review clinically if symptoms fail to improve.

Counselling the patient

  • Swallow with a full glass of water while sitting or standing and do not lie down straight afterwards.
  • Avoid taking it at the same time as indigestion remedies, iron or calcium supplements, or dairy.
  • Use sun protection as your skin may burn more easily.

Evidence & guidelines

NICE guidance on acute sinusitis supports a tetracycline such as doxycycline as an antibiotic option when treatment is indicated in penicillin-allergic adults.

Reference: NICE NG120 Sinusitis; PHE Antibiotic 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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