Pharm Antimicrobials Flashcards
Properties of Tetracyclines
Poorly water soluble
Decreased GI absorption when taken with food except doxycycline and methacycline
High pH decreases absorption
How do tetracyclines work?
Reversibly inhibit the 30s of ribosome preventing charged amino acids from binding to mRNA
What does tetracycline treat?
Chlamydiae, mycoplasmas, rikettsiae, and amebas
What tetracyclines are not effected by efflux pumps?
Doxycycline, minocycline, tigecycline
Three resistance mechanisms for tetratcclines
1) Protein Pumps
2) 30s protection
3) Ezymatic inactivation
Tet A
Efflux expressing gram negative strains that are resistant to all tetracyclines except tigecycline
Tet K
In staphylococcus confers resistance to tetracyclines except doxy, mino, tige
Tet M
Ribosomal protection in Gram + that confers resistance to tetracylines except tige
GI absorption of tetracyclines are impaired by?
Food, dairy products, antacids, higher pH, and cations
Where are tetracyclines distributed in body?
Widely distributed throughout whole body except in the CNS
Can cross placenta, found in breast milk
Why dont you give tetracycline to children?
Prevents long bone growth and teeth deformities in children younger than 8
Metabolism of Tetra
Undergo enterohepatic circulation
Doxy and tige are eliminated through non-renal mechanisms
Proton pump inhibitor with tetra
Used to treat helicobacter pylori induced ulcers. Give proton pump after drug othewise increased pH will inhibit tetra
Demeclocycline
Used in certain ADH secreting tumors
Causes photosensitivity
Adverse effects of kidneys
All tetra cause nitrogen retention and accumulate during renal insufficiency except doxy and tige
