Doxycycline (oral)
Orals / systemic · Rx
Trade namesVibramycin, Oracea (40 mg MR), Doryx, Monodox
Drug classTetracycline antibiotic, systemic (anti-inflammatory at sub-antimicrobial dose)
Strength20 mg, 40 mg modified-release, 50 mg, 100 mg
AvailabilityRx
Mechanism of actionInhibits the bacterial 30S ribosome; independently of any antibacterial effect it suppresses MMP-8/-9, bacterial lipases and pro-inflammatory cytokines, which is the basis for low-dose use in lid and ocular surface disease.
Indication / reason for useInternal hordeolum / acute chalazion and preseptal cellulitis (adjunct, or first choice in penicillin allergy / MRSA risk); meibomian gland dysfunction and posterior blepharitis, ocular rosacea, phlyctenular and marginal keratitis, recurrent corneal erosion.
Usual adult dosingInfection (internal hordeolum, preseptal cellulitis): 100 mg PO twice daily for 7-10 days. Lid / ocular surface disease: 100 mg daily, or 40 mg modified-release daily, or 20 mg twice daily, for 6-12 weeks then taper.
PreservativeN/A (oral) , a preservative-free option exists
Contact lensesNo direct lens interaction; counsel outdoor lens wearers on photosensitivity.
Common / important adverse effectsGI upset, pill oesophagitis (take upright with water, well before lying down), photosensitivity, vaginal candidiasis; rare idiopathic intracranial hypertension, do not combine with isotretinoin or high-dose vitamin A.
Contraindications & cautionsPregnancy and breastfeeding; children under 8 years (dental staining, enamel hypoplasia); separate doses from dairy, antacids, iron and calcium by about 2 h; may reduce oral-contraceptive reliability.
Pregnancy / lactationContraindicated in pregnancy and lactation. Use erythromycin or azithromycin if a systemic agent is needed.
Practice notesFor preseptal cellulitis the primary cover is Staph / Strep (amoxicillin-clavulanate or cephalexin); doxycycline is the alternative in penicillin allergy or MRSA risk and adds an anti-inflammatory effect. Refer any post-septal (orbital) signs, proptosis, pain on eye movement or restricted motility, urgently.
Chair-side reference only. Dosing, contraindications and pregnancy guidance here are not exhaustive. Confirm against the current prescribing information and the patient’s full history before prescribing or advising.