tetracyclines Flashcards
how many rings do tetracycline has
4 rings that are fused together with alternating double bonds
moa of tetracyclines
The drugs bind reversibly
to the 30S subunit of the bacterial ribosome. This action prevents
binding of tRNA to the mRNA–ribosome complex, thereby inhibiting bacterial protein synthesis
how does tetracycline enter the bacterial cell
passive diffusion
OR
energy dependent transport protein mechanism
tetracyclines are bacteriostatic or bactericidal?
bacteriostatic
spectrum of tetracycline
gram-positive and gram-negative
bacteria, protozoa, spirochetes, mycobacteria, and atypical species
resistance against tetracycline
efflux pump
enzymatic inactivation
Uses of tetracycline
Cholera: → Vibrio cholera (Doxycycline).
2) Lyme disease: → Borrelia burgdorferi (tick bite)→doxycycline 200mg.
3) Rocky mountain spotted fever→ Rickettsia ricketsii.
4) Chlamydial infections: → Chlamydia Trachomatous (sexually transmitted).– doxycycline or azithromycin
5) Mycoplasma pneumonia: → also with Macrolides or DOXYCYCLINE
TETRACYCLINES ORAL OR IV
tetracyclines are absorbed orally
Doxycycline and minocycline are available as oral and IV
should tetracycline be used with Milk?
NO– THE reason being that calcium( or any divalent or trivalent ion) form chelates with tetracycline and dec absorption
should tetracycline be given to pregnant women?
NO they cross the placental barrier
Are tetracycline and doxycycline metabolized by liver?
No
is minocycline metabolized by liver?
Yes
how is tetracycline eliminated
excreted unchanged in urine
how is doxycycline eliminated
eliminated in feces via bile.
it can be used in renally compromised pts
adrs of tetracyclines
Gastric discomfort
hepatotoxic
phototoxic
vestibular dysfuntion
benign intracranila htn may occur in adults– pseudo tumor cerebri
