Please note: This is for information only.

Refer to local guidelines for treatment recommendations


  • A tetracycline antibiotic
  • Metabolised by liver and can be used safely in renal impairment (unlike other tetracyclines)
  • Care in hepatic disease
  • Available orally only
  • Endorse inpatient prescription with "sit upright with plenty of fluid" - small risk of oesophageal irritation/ulceration if not taken in an upright position. Can be given with food and/or milk if gastric irritation occurs; doxycycline absorption is unaffected by food or milk (unlike other tetracyclines).
  • An exaggerated sunburn reaction can occur as a photosensitivity reaction. Advise patients to avoid prolonged direct sunlight/sunbeds and to use a sunscreen that absorbs long wave UVA radiation.
  • Avoid doxycycline in pregnancy and lactation as it can affect development of teeth and skeleton.
  • Avoid antacids containing aluminium, magnesium, calcium, oral zinc, iron or bismuth preparation, or any other preparations containing these products e.g. calcium supplements, magnesium hydroxide for hypomagnesaemia. Milk does contain calcium but not in sufficient quantity to affect doxycycline absorption.
  • Care if giving to a patient stabilised on anticoagulant drugs. Rare cases of increased bleeding and PT when a tetracycline added to regime.
  • The serum levels of doxycycline are reduced and may fall below the accepted minimum inhibitory concentration in patients receiving long-term treatment with barbiturates, phenytoin or carbamazepine. Other tetracyclines do not appear to be affected. An alternative antibiotic may be advised - discuss with microbiology.

Main indications

  • Community acquired pneumonia
  • Infective exacerbations of COPD
  • Treatment of chlamydia infections (urethritis, cervicitis, pneumonia).

Active against most strains of:

  • Streptococcus pneumoniae
  • Haemophilus influenzae and Moraxella catarrhalis
  • Staphylococcus aureus including MRSA
  • Atypical pneumonia pathogens (Chlamydia, Q fever)
  • Chlamydia trachomatis

Not active against most strains of:

  • Coliforms
  • Pseudomonas
  • Anaerobes
  • Variable activity against Neisseria gonorrhoea