Doxycycline: clinical use

Prescribing considerations

• Confirm the indication, likely susceptibility and relevant antimicrobial or travel-health guidance.
• Use caution in hepatic impairment or with potentially hepatotoxic medicines.
• Carefully justify use during tooth development, particularly in younger children; exceptional use may be appropriate for severe or life-threatening infection when alternatives are unsuitable.
• Consider oesophageal injury risk and reinforce administration with adequate fluid while upright.
• Avoid excessive sunlight or ultraviolet exposure and advise prompt review if erythema develops.
• Use caution in myasthenia gravis and systemic lupus erythematosus.
• Consider Candida or other non-susceptible organism overgrowth and antibiotic-associated colitis if compatible symptoms develop.

Contraindications and cautions

• Hypersensitivity to doxycycline, another tetracycline or a product excipient.
• Pregnancy according to the selected product information.
• Breastfeeding according to the selected product information.

Monitoring

• Monitor anticoagulation with warfarin or related anticoagulants.
• Monitor ciclosporin appropriately if co-administration is unavoidable.
• Assess liver function where clinically indicated, particularly with hepatic impairment or potentially hepatotoxic therapy.
• Urgently assess visual symptoms or a concerning headache for intracranial hypertension.
• Investigate significant or persistent diarrhoea for antibiotic-associated colitis.

Clinical pharmacology

Doxycycline is a mainly bacteriostatic tetracycline that inhibits microbial protein synthesis. It is almost completely absorbed orally, has high lipid solubility and is excreted largely unchanged in urine and faeces; clinically significant accumulation is not expected solely from renal impairment.

Formulation and product differences

• This product is an immediate-release hard gelatin capsule containing doxycycline hyclate equivalent to doxycycline.
• Doxycycline is also available in the UK in other salts and formulations, including dispersible and modified-release products. Administration instructions and licensed indications are not automatically interchangeable.

Capsule

Route: Oral

Strengths: 50 mg, 100 mg