Tetracycline

How it works

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

Prescribing in practice

• It is contraindicated in pregnancy, breastfeeding and young children because it is deposited in growing bone and teeth, causing permanent discolouration and enamel hypoplasia.
• Absorption is markedly reduced by milk, antacids and iron or other multivalent cations, which should be separated from dosing.
• It can cause photosensitivity, so patients should avoid excessive sun exposure during treatment.

Monitoring

Monitor renal and hepatic function with prolonged or high-burden therapy, particularly in those with pre-existing impairment.

Counselling the patient

• Take it on an empty stomach with water and avoid milk, antacids and iron around the dose.
• Use sun protection as your skin may burn more easily.
• It must not be used in pregnancy or in young children.

Evidence & guidelines

The class effect on bone and dental development underpins long-standing contraindications in pregnancy and early childhood reflected in UK prescribing references.