Tetracyclines

Question 1

Tetracycline

Mechanism

Answer 1

Bacteriostatic

Binding to 30 S ribosomal subunit and inhibit protein synthesis

Question 2

Tetracycline

Spectrum

Answer 2

Spirochete
Mycoplasma
Chlamydia
Rickettsial
Pseudomonas
Proteus

Resistance has been produced in
Shigella
Staphylococcus 
Streptococci
Pneumococci

Question 3

Tetracycline

Indications

Answer 3

Rickettsial (rocky mountain fever)
Chlamydial inf.
Amebiasis

Bacillary inf such as
Cholera
Brucellosis
Tularemia

Salmonella and shigella inf
Alternative to penicillin for anthrax syphilis gonorrhea lyme disease nocardiosis & H influenzae

Doxycycline : prophylaxis traveler’s diarrhea
Demeclocycline: SIADH adjunct

Question 4

Tetracycline

Side effects

Answer 4

GI distress most common (taking with food helps)
Hypersensitivity
Phototoxic recations
Hepatotoxic (especially p women)
Renally impaired patient high BUN
Permanent tooth discoloration, retarded bone growth in children
Minocycline  vestibular toxicity
IV tetracycline phelibitis

Question 5

Tetracycline

Interactions

Answer 5

Dairy products
Iron supp
Antacids
Laxative
Anything containing Al, Ca, Mg

All these can retard tetracycline absorption

Methoxyflurane (Nephrotoxicity)
Barbiturates & phenytoin (decrease antibiotic effect)

Demeclocycline antagonizes ADH so maybe given as a diuretic in SIADH patients