Antibiotics Flashcards
what is the mode of action for tetracyclines?
Inhibit bacterial protein synthesis, binds to ribosomal 30s subunit
what is the spectrum of activity for tetracyclines?
Broad spectrum and bacteriostatic
what are tetracyclines used for?
Lower RTI, acne, rosacea, malaria and Chlamydia
what are the following tetracyclines used for: Democlocyline Doxycycline Lymecycline monocycline oxytetracycline tetracycline tiegracycline
Democlocyline :
Doxycycline: used in malaria and chlamydia:OD
Lymecycline: acne
monocycline: broader spectrum, rarely used
oxytetracycline
tetracycline
tiegracycline: antibiotic structually related
what are side effects of tetracylines?
benign intercranial hypertension
Photosentisation particularly with demclocycline and doxycycline
Discolour teeth under 12
Angioedema • Headache • Nausea, Diarrhoea & vomiting • Hypersensitivity • Photosensitivity reaction • Skin reactions • Systemic Lupus Erythematosus
name 2 patient groups for which tetracyclines are contraindicated
children under 12
Pregnant and breastfeeding - deposits in growing teeth and bones - discolours enamel
how are tetracyclines used in renal impairement?
how are tetracyclines used in hepatic impairement?
renal: avoid all execept doxycline and minocycline
Hepatic : avoid or use with caution
what counselling points must be given when providing tetracyclines
avoid exposure to sunlight/sunlamps, (doxycycline, demecycline )
decreased absorption of : Al, Ca2I,Mg2+ and zinc sales
DOT- democycline,
oespahageal irritation - DMT - doxycycline
minocycline, tetracycline
Give examples of aminoglycosides
Amokacin gentamicin, tobramycin, neomycin,streptomycin
What are common indications of aminoglycosides
Sepsis, meningitis, endocarditis, pneumonia and surgical prophylaxis
Common side effects of aminoglycosides
Nephrotoxicity and ototoxicity
What is a key consideration when prescribing aminoglycosides
Can the patient monitor changes in hearing?
What needs to be monitored for a patient taking an aminoglycosides
Before and during Renal function -caution in renal failure
During Auditory and vestibular function
Serum concentration- monitor to avoid excessive and sub therapeutic levels and prevent toxicity
Must be monitored in parental admin and determined in elderly obese in CF, high doses of renal impairment
Administration of aminoglycosides
Once daily has superseded multiple daily dose
When should concentration be measured
After 3 of 4 doses of a multiple daily dose regimen or after a dose change
How are aminoglycosides excreted
Primarily Renally
When should bloods be taken for aminoglycosides for multiple daily dose regimens
1 hour after IV or IM admin (peak conc )
Just before next dose (trough)
If trough is high then the interval between doses must be increased
If peak is high the dose must be decreased
Mhra aminoglycosides info
Rare cases of ototoxicity- increased risk of deafness in patients with mitochondrial mutations - even for patients where concentration was in range
Must consider the need for aminoglycosides in patients at risk
Genetic testing needed but treatment shouldn’t be delayed
Those with mitochondrial mutations or family history Of ototoxicity should inform doctor or pharmacist before use
Continuous monitoring of auditory and renal function required
Dosing of gentamicin
Loading dose based of patient weight and renal function
Multiple daily dose regimen :
One hour peak conc : 5-10 mg/L
Pre dose trough conc: less than 2mg/l
Endocarditis peak conc: 3-5 mg/l
Endocarditis trough less than 1mg/L
Describe aminoglycosides spectrum of activity
Broad spectrum bacteriacidal
Describe carbapenams spectrum of activity
Broad spectrum
Beta lactase
Many gram positive and gram negative bacteria and anaerobes
carbapenams side effects
Antibiotic associated colitis CNS toxicity (renal impairment) Diarrhoea Rash Injection site reactions
carbapenams indications
Severe or complicated resistant organisms
Which carbapemens are active against a significant organism
Imapenam and meropenem active against pseudamonas aurigonosa
carbapenams are not active against which serious infection
MRSA
Renal and hepatic impairment: carbapenams
Ertapenam- risk of seizures in renal impatient - dose limited to 500mg if eGFR is <30 ml/min
Imipenam - risk of CNS side effects dose reduced if CrCl <90ml/min
Meropenem-dose adjustments in renal impairment
When should carbapenams be avoided
When there is an immediate history of hypersensitivity to beta lactams
Cephalosporins spectrum of activity
Broad spectrum
first gen Cephalosporins indications
Septacemia, UTI ,Skin reactions ,respiratory tract infections (pneumonia and meningitis)
First gen
Gram positive
Staphylococci
Streptococci
First gen Cephalosporins
Cefalexin
Cefradine
Cefadroxil
Side effects of Cephalosporins
Diarrhoea and hypersensitivity
Cross sensitivity
10% in first gen cephlasporins
3-5 % in fourth gen
Patients wit history of immediate hypersensitivity to penicillin and other beta lactams should not receive a cephalosporins
Indications of second gen Cephalosporins
Meningitis
UTI
RESPIRIATIORY
SKIN
Activity of second gen
More gram negative than 1st gen and less gram positive
Examples of second gen Cephalosporins
Cefaclor
Cefoxotin
Cefuroxime
Side effects of second gen Cephalosporins
Antibiotic associated colitis
Hypersensitivity
How to advice someone experience
Severe diarrhoea or longer than 24 hours of contains blood seek medical attention
Examples of third gen Cephalosporins
cefixime, cefotaxime, ceftazidime, ceftriaxone
Side effects of Side effects of second gen Cephalosporins
antibiotic associate colitis, hypersensitivity
indications : third gen Cephalosporins
meningitis, GI infections, UTI, respiratory and skin infection
third gen cephlasporins spectrum of activity
enhanced activity against gram negative bacteria
glycopepticdes spectrum of activity
bactericidal activity against aerobic and aerobic gram positive bacteria including MRSA
no activity against gram negate bacteria
glycopeptides indications
endocarditis, pneumonia, meningitis, skin infections, MRSA and antibiotic associated colitis
glycopeptides side effects
Nephrotoxicity
blood disorders
red man syndrome
ototoxicity
glycopeptides monitoring
auditory function and plasma concentrations
vancomycin dosing based on what initially and following this
initial dosing based on bodyweight
following does adjusted based on serum concentration
duration of action :glycopeptides
teicoplanin is similer but has significantly longer duration of action vancomycin, so can be dosed once daily
vancomycin dosing and monitoring
Trough target
initial dosing based on bodyweight
following does adjusted based on serum concentration
all patients require serum levels measured on second day of treatment before the next dose if renal function is normal and earlier if there is renal impairment
pre dose conc : 10-20 mg/l
IV monitoring :
periodic testing of auditory function
blood counts, urinalysis, hepatic and renal functions periodically
monitor leukocyte cont regularly esp with other drugs causing neutropenia or agrunulocytosis
monitor vestibular and auditory function during and after in elderly - avoid concomitant use with other ototoxic drugs
oral monitoring
serial testing of auditory function to minimise risk of ototoxicity esp in patients with underlying hearing loss
What are the main indications for quinolones
UTI
Respiratory
Eye infections
GI INFECTION
What are the main side effects of quinolones
Nausea and vomiting Diahorrea Hypersensitivity Psychiatric Inc risk of convulsions with NSAIDs Tendonitis - tendon rupture - corticosteroids
small increased risk of aortic aneurysm and dissection
small risk of heart valve regurgitation; consider other therapeutic options first in patients at risk
Quinalone cautions
Seizures G6pd deficiency Qt prolongation exposure to excessive sunlight and UV radiation should be avoided during treatment and for 48 hours after stopping treatment; Myasthenia gravis Diabetes
Common interactions with quinolones
Milk or antacids or vitamin supplements containing iron or zinc
Avoid NSAIDS
Which antibiotic is most associated with antibiotic associated colitis
What other groups can cause it
Clindamycin Broad spectrum (penicillins ,cephalosporin, fluoroquinalones )
Warning sign for antibiotic associated colitis
If diahorrea develops stops
Who are most likely to develop antibiotic associated colitis
Women elderly and those who have just had surgery
Antibiotics used against MRSA
Vancomycin and linezolid
Linezolid side effects
Blood disorders
Optic neuropathy if used greater than 28 days
Possible hypertensive crisis
Antibiotic for CDIFF infection
Vancomycin 125 mg every 6 hours for 10 days; increased if necessary to 500 mg every 6 hours for 10 days, increased dose if life-threatening or refractory infection.
Fidoxomicin
contraindications with aminoglycosides
myasthenia gravis
interactions with ahminoglycosides
cisplatin and furosemide
monitoring aminoglycosides
renall function
auditory and vestibular function -
serum concentration
examples of glycopeptides
vancomycin, teicoplanin , telavancin
mode of action of glycopeptide
bacteriacidal inhibit cell wall synthesis
spectrum of coverage for glycopeptides
gram positive( aerobic and anaerobic )
enterococci, staphylococci, streptococci
patient groups that should avoid use of aminoglycosides
elderly and those with history of auditory problems
how are aminoglycosides and glycopeptides used together in treatment of infective endocarditis
aminoglycosides have mainly gram negative coverage and so cover those organisms and glycopeptides cover gram positive broadly
drugs to avoid using with
ototoxic drugs- furosemide
ciclosporin, ahminoglycosides, polymixin antifungals
