Protien Synthesis Inhibitors Flashcards
Which are the antibiotics that bind to 30S ribosome
Aminoglycosides, tetracycline
What are the antibiotics that bind to 50s ribosome
CELLS
Chloramphenicol
Erythromycin
Lincosamide
Linezolid
Streptogramins
What is the mode of action for aminoglycosides
Bactericidal
Explain the pharmacokinetics of aminoglycosides
Not well absorbed orally so must be given IV or IM
Limited distribution due to polarity
What is the mechanism of action for aminoglycosides
Inhibit protein synthesis by binding to the 30S ribosome, leading to mRNA misreading causing production of abnormal proteins and causing bacterial cell death
Explain why bacterias are resistant to aminoglycosides
Production of inactivating enzymes called group transferases
Or due to decreased penetration of aminoglycosides
What are the adverse effects of aminoglycosides
Ototixicity- damage to cochlea and vestibular apparatus results in impaired hearing and balance
Nephrotoxicity- tubular damage resulting in LOW GFR and loss of urinary concentrating capacity
Neuromuscular juntion blockade
Gentamicin is an aminoglycoside. What is its clinical use
Enterococci
What is gentamicin and tobramycin used for?
Conjunctivitis caused by gram negative bacteria
What is streptomycin( aminoglycoside) used against
Tuberculosis
What is neomycin used against
Given orally to suppress the gut flora in hepatic encephalopathy
What is spectinomycin (aminoglycoside) used for?
backup for TB and gonorrhea
What is the mode of action for tetracycline
Bacteriostatic
What is the spectrum of tetracycline
Broad
What are the short acting tetracycline drugs
Tetracycline, Oxytetracyline
What are the intermediate acting tetracyclines
Demeclocycline, methocycline
What are the long acting tetracycline drugs
Doxycycline, minocycline
What is the mechanism of action for tetracyclines
Binds to 30S ribosomal subunit and prevents binding of tRNA to mRNA, which prevents the addition of amino acids to the growing peptide
What is the mechanism of resistance for tetracyclines
Efflux pumps develop that cause decreased uptake
What are the clinical uses of tetracycline
Primary uses include:
In infections caused by mycoplasma pneumoniae, chlamydiae, rickettsia spirochetes, legionella
Secondary uses: alternative drug used in syphillis
Treatment of leptospirosis
Treatment of propionibacterium acne
What is doxycycline used for
Used to treat periodontal disease
Also for prostatitis
What are the adverse effects of tetracycline
Pseudomembranous colitis , superinfection caused by C. Difficile
Tetracyclines decrease absorption of iron, magnesium, aluminium and zinc
Irritation of GI tract
Hepatic toxicity due to high doses (lead to necrosis especially in pregnant women)
Renal toxicity by using outdated tetracyclines
Photosensitivity
(especially caused by demeclocycline and doxycycline)
Vestibular toxicity
What is the mode of action of macrolides
Bacteriostatic
Give some examples for macrolides
Erythromycin, clarithromycin, azithromycin
What is the mechanism of action of macrolides
Binds to 50S subunit
Inhibits polypeptide chain elongation and protein synthesis inhibitors which then inhibits bacterial growth and multiplication
What are the clinical uses of macrolides
Treatment of
-Legionnaires disease
-Diphtheria
-Whooping cough
-Chlamydial infections
-Syphilis
Drug of choice for community acquired pneumonia caused by mycoplasma legionella and chlamydia
What is the adverse effect of macrolides
GI disturbances
Hepatic elimination ( contraindicated in patients with liver disorders)
What is clindamycin used for?
Used for bacteroides fragilis
Prescribed for prophylaxis of endocarditis
What are the adverse effects of lincosamides
Bleeding tendencies such as agranulocytosis and hypersensitivity
What is the mode of action for chloramphenicol
Broad spectrum antibiotics
What is the spectrum of chloramphenicol
Broad spectrum
What is the mechanism of action
Binds to bacterial 50S subunit and blocks transpeptidation and prevents protein synthesis
What is the therapeutic use for chloramphenicol
Alternative for cephalosporin in meningitis, brain abcess
Alternative for tetracycline in rocky mountain spotted fever
Enteric fever
What are the adverse effects of chloramphenicol
Fatal aplastic anemia
Grey baby syndrome
What is the therapeutic use of spectinomycin
Anogenital gonorrhoea
What is the adverse effects of spectinomycin
Urticaria, dizziness, nausea, chills, fever, insomnia
What is the therapeutic use for streptogramins?
Methicilin resistant S. aureus and VRSA
What are the adverse effects of streptogramin
Hepatotoxic, so bilrubin test should be performed twice
What is the mode of action for linezolid
Bacteriostatic
What is the mechanism of action for linezolid
Binds to 50S and prevents protein synthesis, inhibits formation of the initiation in translation
Therapeutic use of linezolid
Vancomycin resistant E. faecium
Adverse effects of linezolid
Headache and GI Distress
