Tetracyclines Flashcards
Give some examples of tetracyclines.
Tetracycline, doxycycline, minocycline (broad spectrum).
What is the mechanism of action of the tetracyclines?
Taken into bacterial cells and prevent binding of aminoacyl tRNA, preventing protein synthesis and halting cell growth.
Give some indications tetracyclines are used to treat.
Chlamydia, rickettsia, acne, rosacea.
For how long are tetracyclines used to treat acne?
Up to 6 months.
What important advice is required when counselling patients being treated with tetracyclines for acne?
An improvement may not be seen for 8 weeks, persist with treatment.
What are the side effects of the tetracyclines?
Nausea, vomiting, diarrhoea, antibiotic-associated colitis, dysphagia, oesophageal irritation, hepatotoxicity, blood disorders, photosensitivity, hypersensitivity.
What may a headache and visual disturbances whilst a patient is being treated with tetracyclines suggest?
Benign intracranial hypertension. Discontinue treatment.
Tetracyclines may increase muscle weakness in which patients?
Myasthenia gravis.
Which autoimmune condition may tetracyclines exacerbate?
Lupus erythematosus.
In which groups are tetracyclines contraindicated due to deposition in growing bones and teeth?
Children under 12 years, pregnant and breastfeeding women.
Are tetracyclines contraindicated in patients with renal and hepatic impairment?
Yes.
Which substances decrease the absorption of the tetracyclines?
Antacids, aluminium, calcium, iron magnesium, zinc salts.
Which food/drink decreases the absorption of demecycline, oxytetracycline and tetracycline?
Milk.
How should tetracycline tablets, doxycycline capsules, minocycline tablets or capsules be taken?
Swallowed whole with plenty of water, stood up or sitting.
