macrolides, clindamycin and linezolid Flashcards
what type of macrolides are there
erythromycin, azithromycin, clarithromycin
are macrolides bacteriostatic or bactericidal
bacteriostatic
What is the mechanism of action for macrolides
inhibit proten synthesis by reversibly binding to 50S ribosomal subunit
inhibit translocation step, nascent peptide chain residing at the A site of the transferase reaction fails to move to the peptidyl donor site
what is the problem with macrolide in terms of metabolism
it inhibits cp450 enzymes, therefore results in many drug drug interactions
What is erythromycin used to treat
treat community acquired pneumonia, s. pneumoniae, atypical bacteria
what is clarithromycin used to treat
higher activity against atypical bacteria than erythromycin
eg. legionella, helicobacter pylori
what is azithromycin use to treat
more active than erythromycin against respiratory infections due to H. influenzae and moraxella catarrhalis
What is azithromycin prefered for
STD caused by chlamydia trachomatis and neisseria gonorrhoea
What are the adverse effects of macrolides
GI distress and mobility
hepatotoxicity
ototoxicity
May prolong QT interval, used in caution with patients with pro arrhythmic condition
Who is contraindicated for macrolide
patients with hepatic dysfunction
clarithromycin cat C
How does erythromycin and clarithromycin affect accumulation of other compounds
they inhibit c450 enzymes, potentiating effects of these drugs like corticosteroids, digoxin and warfarin through the interference of CYP mediated metabolism of these enzymes
What is clindamycin very useful for
very useful against anaerobic infection
what is the mechanism of action for clindamycin
binds exclusively to 50s subunit of bacterial ribosomes and inhibit peptide synthesis
what is clindamycin not used with
macrolides, as they can act at sites of proximity, can antagonise each other
what can clindamycin have a high risk of causing
CDAD
what are the indications for clindamycin
MRSA, streptococcus, penicillin resistant anaerobic bacteria
anaerobic infection of skin and soft tisssue caused by bacteroides, clostridiodes perfringens
Good spectrum of activity against oral pathogens. 50% of oral pathogens caused by anaerobes, excellent alternative to penicillin for treatment of dental abscesses because of bacterial susceptibility to drug
prophylaxis against endocarditis prior to dental procedures in patients with acquired valvular damage, congenital heart disease, valve replacement, cardiomyopathy
What is resistant to clindamycin
almost all aerobic gram negative bacteria
what is the administration for clindamycin
IV and Oral, can be topical solution, gel or lotion
How is the distribution of clindamycin
excellent bone and salivary gland production
poor entry into CSF
How is clindamycin metabolised
hepatic
What are the adverse effects of clindamycin
skin rashes,
CDAD diarrhoea, take full glass of water to reduce esophageal irritation
what does linezolid covers
only gram positive
what is the mechanism of linezolid
binds to 23 S ribosomal RNA of 50s subunit, prevent formation of functional 70S inititation complex, an essential component of bacterial translation
prevents formation of initiation complex
What is linezolid good for
Staph, strep, enterococci, listeria monocytogenes
Good for penicillin resistant strain of S.pneummoniae, MRSA, VRSA, VRE
why is linezolid not good for gram negative bacteria
because efflux pump force linezolid out of cell faster than it can accumulate
How can linezolid be administered
orally and IV
How is the distribution of linezolid
widely distributed, good penetration into CSF
what are some adverse effects of linezolid
GI effect: nausea, diarrhea, headache rash
Bone marrow supression: leading to thrombocytopenia
Can have non selective monoamine oxidase inhibitor activity leading to serotonin syndrom
Irreversible peripheral neuropathies and optic neuritis associated with more than 28 days of use
