DR. MABANAG - MACROLIDES, CLINDAMYCIN, CHLORAMPHENICOL, STREPTOGRAMINS & OXAZOLIDINONES Flashcards
A group of closely related compounds characterized by a long macrocyclic lactone ring (usually containing 14 or 16 atoms) to which deoxy sugars are attached.
MACROLIDES
● Prototype drug consists of 2 sugar moieties attached to a 14-atom lactone ring
● Obtained in 1952 from Streptomyces erythraeus now called as Saccharopolyspora erythraea
ERYTHROMYCIN
discovered in Iloilo City by Dr. Abelardo Aguilar but not given the credit
Streptomyces erythraeus
first brand name of Erythromycin because it was discovered in Iloilo City.
ILOSONE
are semi-synthetic derivatives of erythromycin
CLARITHROMYCIN
AZITHROMYCIN
○ Inhibition of protein synthesis occurs via
binding to the 50S ribosomal RNA
- Activities enhanced at alkaline pH
ERYTHROMYCIN
● Active against susceptible strains of G(+) organisms especially pneumococci, streptococci, and the corynebacteria.
○ Mycoplasma pneumoniae
○ Legionella pneumophila
○ Chlamydia trachomatis
○ Chlamydophila psittaci
○ Chlamydophila pneumoniae
○ H. pylori
○ Listeria monocytogenes
ERYTHROMYCIN
● Certain mycobacteria are also susceptible
(non-tuberculous mycobacteria):
○ Mycobacterium kansasii
○ Mycobacterium scrofulaceum
ERYTHROMYCIN
● Gram-negative organisms susceptible strain
○ Neisseria sp
○ Bordatella pertussis
○ Bartonella henselae
○ Bartonella quintana
ERYTHROMYCIN
● Rickettsia species
○ Treponema pallidum
○ Campylobacter species
● Haemophilus influenzae is somewhat less
susceptible
ERYTHROMYCIN
MACROLIDES PHARMACOKINETICS
- DESTROYED BY STOMACH ACIDS
- FOOD INTERFERES WITH ABSORPTION
- NOT REMOVED BY DIALYSIS
- BILE EXCRETION
- CAN CROSS PLACENTA
MACROLIDES ADVERSE REACTIONS
- GI SYMPTOMS
- GI INTOLERANCE
- ACUTE CHOLESTATIC HEPATITIS
- INHIBITS CYP450
= ↑ serum concentration of theophylline, warfarin, cyclosporine, and methylprednisolone so decrease the dose
Inhibits CYP450 system
MACROLIDES
for cardiac rhythm abnormalities
DIGOXIN
● Derived from erythromycin by addition of a methyl group with ↑ stability in oral absorption
● Same mechanism of action and spectrum activity with erythromycin, except: clarithromycin is more active vs Mycobacterium avium complex
CLARITHROMYCIN
Major metabolite: 14-hydroxyclarithromycin; has antibacterial activity and is eliminated in the urine
CLARITHROMYCIN
● A 15-atom lactone macrolide ring compound derived from erythromycin by addition of a methylated nitrogen into lactone ring
AZITHROMYCIN
do not alter bioavailability but delay absorption and ↓ peak serum concentrations
Al- and Mg3 (Aluminum and magnesium) antacids
Does not inactivate CYP450 compared to
erythromycin and clarithromycin (lesser
drug interactions)
AZITHROMYCIN
Semisynthetic, 14-membered-ring macrolides, differing from erythromycin by substitution by substitution of a 3-keto group for the neutral sugar L-cladinose
KETOLIDES
● Active in vitro vs
○ Streptococcus pyogenes
○ S. pneumoniae
○ S. aureus
○ H. influenza
○ Moraxella catarrhalis
○ Mycoplasma spp.
○ L. pneumophila
○ Chlamydia sp.
○ H. pylori
○ Neisseria gonorrhoeae
○ B. fragilis
○ T. gondii
○ Certain nontuberculous bacteria
KETOLIDES
causes QT prolongation
Erythromycin, Clarithromycin, Azithromycin, & Ketolides (Telithromycin)
● More widely used
● Chlorine-substituted derivative of Lincomycin
CLINDAMYCIN
** parent compound of clindamycin
LINCOMYCIN
○ Interfere with: formation of initiation complexes; aminoacyl translocation
reactions
○ 50s binding site
CLINDAMYCIN
○ Susceptible: Streptococci, staphylococci,
pneumococci inhibited by clindamycin
○ Resistant: Enterococci and Gram-negative
aerobic organisms
CLINDAMYCIN
○ Penetrates well into abscesses - actively
taken up and concentrated by phagocytic cells
CLINDAMYCIN