What are they?
Tetracyclines are a class of antibiotics, comprising plain tetracycline as well as modified tetracyclines such as doxycycline and minocycline, which are used to treat skin and other infections. Because of their anti-inflammatory properties, they are also used to treat a range of skin conditions including acne, rosacea, periorificial dermatitis and bullous pemphigoid.
What precautions are needed when taking them?
Tetracyclines should be avoided in cases of:
- Allergy to this medication
- Those under eight years of age (affects teeth and bones)
- Severe liver and kidney disease
Tetracyclines also interact with medications including:
- Retinoids (isotretinoin, acitretin)
- Vitamin A
- Oral contraceptives (tetracyclines may possibly reduce effectiveness of the pill)
- Warfarin (a blood thinner)
One should avoid supplements containing iron and calcium as well as antacids containing aluminium, magnesium or zinc since these can reduce the absorption of tetracyclines. It is advisable to take the medication with a big glass of water, especially plain tetracycline.
Other drug interactions are possible and it is important to check with your doctor prior to taking any new medications.
What to expect while taking these and possible side effects
Most people tolerate this medication well but there are some uncommon side effects including:
- Gastric upset causing nausea, vomiting diarrhoea or abdominal burning
- Greater risk of sunburn
- Oral or vaginal thrush
- Yellowing of the teeth in people less than 8 years of age
- Skin rash
- Skin pigmentation with long-term use
- Intracranial hypertension
They can rarely cause a severe allergic reaction including hives, swelling of lips and tongue as well as breathing difficulty or inflammation of the liver.
What monitoring is required when taking these?
Blood test monitoring is not usually required. Liver function tests may be needed in some cases, depending on the individual’s medical history.
This information has been written by Dr Elizabeth Dawes-Higgs and Dr Ajay Kumar
Last updated 27/04/2017