Tetracyclines, Macrolides, Clindamycin, Chloramphenicol, Streptogramins and oxazolidinones Flashcards
A 4 year old child is brought to the hospital after ingesting pills that a parent hasd used for bacterial dysentery. The child has been vomiting for more than 24 h and had diarrhea with green stools. She is now lethargic woth ashen color. Other signs and symtpoms include hypothermia and hypotension, and abdominal distention. The drug most likely to caue this problem is
Chloramphenicol
Tetracycline are the DOC for RMSF and lyme disease. the mechanism of antibacterial action involves _______
Interference with binding of aminoacyl-tRNA to bacterial ribosomes
Peptidyl transferase is inhibited by _________
cholramphenicol
Clarithromycin and erythromycin have very similar spectra of antimicrobial activity. The major advantage of clarithromycin is that it
Has greater activity against H. pylori
- M. avium complex
- T. gondii
- Clarithromycin is adminsitered less frequently than erythromycin
The primary mechanism of resistance of gram positive organisms to macrolide antibiotics including erythromycin is
Methylation of binding sites on the 50S ribosomal subunit
A 26 year oold woman wsa treated for a suspected chlamydial infection at a neighborhood clinic. She was given a prescription for oral doxycline to be taken for 14 days. However patient was non compliant. whats the next step of management?
Treat her in the clinic with a single dose of oral dose of azithromycin
A 55 year old patient with a prosthetic heart valve is to undergo periodontal procedure. What is prophylaxis of choice if the aptient is allergic to Penicillin G?
Clindamycin 1 h before the procedure
____________ sometimes with gentamicin is recommended for prophylaxis in high risk penicillin-allergic patients undergoinf genitourinary and lower GI surgical procedures?
IV vancomycin
Eythromycin can cause cardiac or CNS toxicity with excessive ingestion of _________
caffeine
A 5-d course treatment for CAP would be effective using _______________
Azithromycin
____________ is an effective drug in treament of MDR streptococcal infections
Quinupristin-dalfopristin
- E. Faecium
- Bactericidal
- Not hepatotoxic
Tetracyclines
(Tetracycline, Doxycycline,Minocycline,Tigecycline)
Binds to 30S ribosomal subunit; Bacteriostatic; tigecycline has the broadest specturm adn resitance is less common (too large for efflux pum)
USed in infections due to chlamydiae, mycoplasma, rickerssiae, spirochetes, and H. pylori; treatment of acne (low dose)
Oral, IV. renal and biliary clearance. Doxycycline main GI elimination and long half life
SE: GI upset, deposition in developing bones, and teeth, photosensitivity, superinfection
Macrolides
(Erythromycin, Azithromycin, Clarithromycin, telithromycin)
Bind to 50S ribosomal subuniut; bacteriostatic. Least resistance to telithromycin (too large for efflux pump)
Used in CAP, pertussis, corynebacteria, and chlamydial infections
Oral. IV for erythromycin, azithromycin. Hepatic clearance, azithromycin long half life (>40h)
SE: GI upsets, hepatic dysfunction. QT prolongation, CYP450 inhibition (not azithromycin)
Lincosamide
(Clindamycin)
Bind to 50s ribosomal subunit. bacteriostatic
Used in skin, soft tissue, and anaerobic infections
Oral. IV. hepatic clearance
SE: GI upsets. C. Difficile colitis
Streptogramins
(Quinupristin-dalfopristin)
Binds to 50s ribosomal subunit. bactericidal
Used in staphylococcal infections, vancimycin-resistant E.faecium
IV. renal clearance
SE: infusion related arthralgia and myalgia. CYP450 inhibition
