Tetracyclines Flashcards
1
Q
Give an example + what spectrum of activity do they have
A
Doxycycline
- broad
2
Q
What are the indications for use
A
- Acne vulgaris esp. inflamed papules/pustules
- LRTI - infective exacerbation COPD (H. influenza), pneumonia + atypical pneumonia
- Chlamydia infection (including pelvic inflammatory disease)
- Typhoid, antrax, malaria, lyme disease
3
Q
What is the mechanism of action
A
- Inhibit bacterial protein synthesis by binding to 30S ribosomal subunit
- Prevents binding of transfer RNA to mRNA –> preventing addition new AAs to polypeptide chains
- BACTERIOSTATIC.
4
Q
What are the side effects
A
- N/V, diarrhoea
- Hypersensitivity reactions
- oesophageal irritation/ ulceration
- Dysphagia
- Photosensitivity
- Discolouration/ hypoplasia of tooth enamel (esp children)
- Intracranial HTN (headache, visual disturbance)
5
Q
What are the contra-indications
A
- Pregnancy, breastfeeding
- Children <12
- Renal impairment (anti-anabolic effects raise plasma urea & reduce excretion can inc risk of SE)
6
Q
What are the interactions
A
- Bind to divalent cations –> not given w. ANTACIDS, CALCIUM, IRON (prevent antibiotic absorption)
- can enhance effects WARFARIN by killing normal gut flora that synthesise vitamin K
