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Tetracycline antibiotic Pregnancy: Should not be used during pregnancy unless considered essential. Tetracyclines cross the placenta and may have toxic effects on foetal tissue, particularly on skeletal development. The use of tetracycline compounds during pregnancy has been associated with reports of maternal liver toxicity. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be appraised of the potential hazard to the foetus. Breast-feeding: tetracyclines are also excreted in breast milk and are therefore contra-indicated in nursing mothers. Use in newborns, infants and children: all tetracyclines form a stable calcium complex in any bone-forming tissue; a decrease in fibula growth rate has been observed in premature infants given oral tetracycline, and this reaction was reversed when the drug was discontinued. (SPC §4.6)

Oxytetracycline

Brand names: Imperacin

Oxytetracycline is a tetracycline antibacterial used for infections such as acne, rosacea, respiratory and genital infections including those caused by Chlamydia.

Adult dose

Dose: Adults: infections caused by oxytetracycline-sensitive organisms (the SPC lists chronic bronchitis, pneumonia, urinary tract infections, brucellosis, pertussis, rickettsial fevers and psittacosis) - one 250 mg tablet (oxytetracycline dihydrate 250 mg) four times a day; this may be increased to 6 or 8 tablets daily in severe infections. Continue therapy for up to three days after symptoms have subsided. Children: use a children's formulary (contraindicated under 12 years).
Route: Oral
Frequency: Four times a day, one hour before or two hours after meals
Product: UK SPC via MHRA Products - OXYTETRACYCLINE TABLETS BP 250MG (PL203950134), Relonchem Limited. SPC §2: 'Each tablet contains oxytetracycline dihydrate 250 mg'. §4.1 (verbatim): 'Oxytetracycline tablets are indicated in the treatment of infections caused by oxytetracycline-sensitive organisms. These include chronic bronchitis, pneumonia, urinary tract infections, brucellosis, pertussis, rickettsial fevers and psittacosis.' The SPC does NOT print an acne or rosacea regimen (the page also carries Dermatology), so none is written. §4.2 (verbatim): 'Oxytetracycline should be given one hour before or two hours after meals, since food and some dairy products interfere with absorption. Therapy should be continued for up to three days after symptoms have subsided. Route of administration: Oral. Adults and children over 12: One tablet four times a day. This may be increased to 6 or 8 tablets daily in severe infections. Children: Not recommended for children under 12 years. Elderly: Oxytetracycline tablets 250 mg should be used with caution in the treatment of elderly patients where accumulation is a possibility.' The SPC heading also names children over 12; that age group is deliberately not reproduced here - under-18s: use a children's formulary. The SPC prints no separate maximum dose; the highest regimen printed is 8 tablets daily in severe infections. §4.3: 'Must not be given to children under 12 years.' §4.4: tetracyclines may cause permanent tooth discolouration if administered during tooth development, in the last half of pregnancy and in infancy up to twelve years of age; enamel hypoplasia has also been reported. If GI irritation occurs, tablets should be taken with food (§4.8). Excipients: the tablets contain sucrose (191.18 mg) and sodium benzoate; patients with fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency should not take this medicine (§2, §4.4). Care is advised in myasthenia gravis (§4.4).

Dose adjustments

Renal

No dose-reduction schedule is printed. Chronic renal dysfunction is a contraindication (SPC §4.3); §4.4: 'The use of tetracyclines in general is contraindicated in renal impairment due to excessive systemic accumulation'; in significantly impaired renal function higher serum levels may lead to azotaemia, hyperphosphataemia and acidosis. Elderly: use with caution where accumulation is possible (SPC §4.2).

Hepatic

No dose-reduction schedule is printed. Chronic hepatic dysfunction is a contraindication (SPC §4.3); SPC §4.4: use with caution in patients with hepatic impairment or those receiving drugs which may have hepatotoxic effects; high doses should be avoided.

Dose independently re-sourced from UK Summary of Product Characteristics (SPC) via MHRA Products — clinician-reviewed. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to any of the tetracyclines or to any of the other excipients (SPC §4.3)
  • Children under 12 years (SPC §4.3)
  • Chronic renal or hepatic dysfunction (SPC §4.3)
  • Pregnancy or breastfeeding women (SPC §4.3)
  • Systemic lupus erythematosus (SLE) (SPC §4.3)
  • Patients receiving vitamin A or retinoid therapy (SPC §4.3)

Side effects

  • Gastro-intestinal irritation: nausea, abdominal discomfort, vomiting, diarrhoea, anorexia, dysphagia - frequency not known (take tablets with food if it occurs); rare: oesophagitis and oesophageal ulceration
  • Pseudomembranous colitis; intestinal overgrowth of resistant organisms (Candida albicans in particular) causing glossitis, rectal and vaginal irritation and inflammatory lesions in the anogenital regions; resistant staphylococci may cause enterocolitis - frequency not known
  • Tooth discolouration; pancreatitis - frequency not known
  • Hepatotoxicity (hepatitis, jaundice and hepatic failure), fatty liver degeneration - frequency not known
  • Photo-erythema and macropapular / erythematous rashes - frequency not known; uncommon: exfoliative dermatitis
  • Hypersensitivity reactions: urticaria, angioneurotic oedema, anaphylaxis, anaphylactoid purpura, pericarditis, exacerbation of systemic lupus erythematosus - frequency not known
  • Benign intracranial hypertension; bulging fontanelles in infants - frequency not known (stop treatment if raised intracranial pressure occurs)
  • Haemolytic anaemia, thrombocytopenia, neutropenia and eosinophilia; renal dysfunction - frequency not known
  • Brown-black microscopic discolouration of thyroid tissue in use over prolonged periods (no abnormalities of thyroid function are known to occur)

Interactions

  • Antacids and preparations containing aluminium, calcium, iron, magnesium or zinc impair absorption - allow two to three hours between doses (SPC §4.5)
  • Some foods and dairy products may interfere with absorption; kaolin-pectin and bismuth subsalicylate hinder absorption (SPC §4.5)
  • Retinoids and vitamin A: increased incidence of benign intracranial hypertension - concurrent use is contraindicated (SPC §4.5)
  • Anticoagulants: oxytetracycline depresses plasma prothrombin activity and may prolong the action of coumarin anticoagulants - a downward adjustment of the anticoagulant dose may be required (SPC §4.4/§4.5)
  • Diuretics: combination may be detrimental to renal function; methoxyflurane or other nephrotoxic drugs: nephrotoxicity and death reported (SPC §4.5)
  • Penicillins: bacteriostatic drugs may interfere with the bactericidal action - should not be given concurrently (SPC §4.5)
  • Oral contraceptives: a few cases of pregnancy or breakthrough bleeding reported - alternative contraceptive advice should be sought where necessary (SPC §4.5)
  • Insulin and sulphonylureas: hypoglycaemic effects may be increased (SPC §4.5)

Monitoring

  • In long-term therapy, periodic laboratory evaluation of organ systems including haematopoietic, renal and hepatic studies (SPC §4.4)
  • When treating venereal disease where co-existent syphilis is suspected, proper diagnostic procedures and monthly serological tests for at least four months (SPC §4.4)
  • Symptoms of benign intracranial hypertension (headache, visual disturbance) - cease treatment if they develop (SPC §4.4)
  • Photosensitivity - advise avoiding direct natural or artificial sunlight; discontinue at the first sign of skin discomfort (SPC §4.4)
  • Overgrowth of non-susceptible organisms including Candida - constant observation is essential; if a resistant organism appears, discontinue and institute appropriate therapy (SPC §4.4)

Clinical monograph

How it works

It binds reversibly to the bacterial 30S ribosomal subunit, preventing aminoacyl-tRNA binding and inhibiting protein synthesis to give a bacteriostatic effect.

Prescribing in practice

  • It is contraindicated in pregnancy, breastfeeding and in children, as deposition in developing bone and teeth causes permanent staining and enamel defects.
  • Absorption is reduced by milk, antacids and iron, calcium, magnesium or zinc salts, which should be separated from dosing.
  • It can cause photosensitivity and should be used with caution in renal impairment, where tetracyclines may accumulate.

Monitoring

Routine monitoring is not usually required for short courses; review renal function with prolonged use or in renal impairment.

Counselling the patient

  • Take it on an empty stomach with water and avoid milk, antacids or mineral supplements around the same time.
  • Use sun protection as your skin may burn more easily.
  • Do not take it if you are or might be pregnant or breastfeeding.

Evidence & guidelines

The contraindication in pregnancy and childhood from dental and skeletal effects is well established and documented in current prescribing references.

Reference: NICE NG198 acne; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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