12. Tetracyclines and glycylcyclines

Question 1

Tetracyclines

Answer 1

**Tetracycline

Oxytetracycline

Doxycycline

Minocycline
——————————————————————————–**

• bind irreversibly to 30s ribosomal subunit
• broad spectrum
• activity against MRSA

-activity against tick borne bacteria
(Rickettsia, Erlichia, Francisella, Borrelia)

• activity against Brucella
• treats culture negative endocarditis caused by coxiella
• activity against yersenia
• treats chlamydial cervicitis and urethritis
• treats chlamydial pelvic inflammatory disease
• treats chlamydial bronchitis and atypical pneumonia
• treats atypical “walking” pneumonia by Mycoplasma
• treat acne
• Causes tooth discoloration in young children
• deposits in fetal teeth and **bone
• ——————————————————————————-**
• multivalent cations (calcium, iron, magnesium) decrease absorption
• GI side effects (nausea, vomiting, diarrhea)
• Photosensitivity
• Fanconi syndrome (type 2 RTA) associated with use of expired tetracycline’s
• resistance via efflux pumps, and alteration of ribosome
• eliminated fecally, safe in renal failure patients

Question 2

Glycyl-cyclines

Answer 2

Tigecycline - Minocycline derivative

• Protein synthesis inhibitor S​ 30 subunit​ - r​eversible​ inhibition
• Bacterio​static
• ​MRSA, VRE, tetracycline resistant
• IV
• l​arge Vd, low plasma concentration
• B​ile (long elimination half-life)
• similar to tetracyclines →Pancreatitis (may be fatal)