C.12. Tetracyclines and Glycylcyclines Flashcards
list the mechanisms of action of Tetracyclines
- binds to the 30S ribosomal subunit–> inhibit binding of charged tRNA to the acceptor site
- act as chelators. they bind to divalent cations (Ca², Mg², Fe²)–> ↓ their absorption
- accumulation in bone and teeth (due to ↑ Ca² content)
- bacteriostatic effect
do Tetracyclines enter the CNS?
no
list the tetracyclines
Tetracycline
Minocycline
Doxycycline
Demeclocycline
what is Tigecycline?
a Glycylcycline
derived from tetracycline
contraindications of Tetracyclines
children<10 years of age
pregnancy
pre-existing liver disease
which tetracycline is safe to use in renal dysfunction?
Doxycycline
how is Tigecycline given?
IV only
how are tetracycline, Minocycline and Demeclocycline given?
orally
what is the T1/2 of Tigecycline?
40 hours
how is Tigecycline excreted?
in the bile
how is Doxycycline excreted?
in the feces
what are the side effects of Tetracyclines and Glycyclcyclines?
- GI distress (superinfections may lead to severe colitis or candidiasis)
- Enamel dysplasia, bone growth abnormalities
- Hepatotoxicity
- Nephrotoxicity (RTA,Fanconi syndrome)
- Photosensitivity
- Vestibular toxicity (dose-dependent, reversible)
- Teratogenic
spectrum and clinical use of Tetracycline
broad:
- gram - and + aerobes, anaerobes, intracellular, spirochetes
- chlamydia (3rd choice) & mycoplasma
- Rickettsia, Vibrio, H. pylori
clinical use of Minocycline
Meningococcal carrier state
Dental procedures
clinical use of Doxycycline
- alternative treatment to macrolides in community-acquired pneumonia
- 2nd line for campylobacter enteritis (1st is macrolides)
- Gonorrhea, chlamydia
- zoonotic diseases
- acne treatment (propionibacterium acne)
