INFECTIONS- AMINOGLYCOSIDES + GLYCOPEPTIDES Flashcards
What is MOA of amino-glycosides?
Active against many gram
-ve and some gram +ve.
Binds irreversibly to bacterial ribosomes
What is spectrum of amino-glycosides?
Broad
Are amino-glycosides bactericidal or bacteriostatic?
bactericidal
What are 5 drugs within amino-glycosides class?
- Amikacin
- gentamicin
- neomycin
- streptomycin
- tobramycin
What pathogen is amikacin used for?
Gentamicin resistant Gram -ve bacilli.
What is the choice drug within amino-glycosides ?
Gentamicin
What route is toxic in neomycin administration?
Parenteral
What is neomycin used in?
Bowel sterilisation
What is streptomycin used for?
TB
What is tobramycin used for when inhaled
Pseudomonal infection in cystic fibrosis
What do amino-glycosides have a risk of in patients with mitochondrial mutations?
Ototoxicity - deafness
monitor renal + auditory function
What condition is injectable amino-glycosides contra-indicated in?
Myasthenia gravis
What are amino-glycosides used in?
Serious infections
e.g. pseudomonas aeruginosa infection
What is typical route of amino-glycosides?
Parenteral
What is therapeutic index of gentamicin POST- DOSE (peak)?
5-10mg/L
What is therapeutic index of gentamicin PRE-DOSE (trough)?
< 2mg/L
What are pre and post dose levels of gentamicin in endocarditis like?
lower
3-5 mg/l post dose (peak)
<1 mg/l pre dose (trough)
How often should gentamicin dose be monitored?
After 3-4 doses
then every 3 days + after dose change.
What is target trough amino-glycoside dose level in endocarditis?
<1 mg/l pre dose
What to do if peak levels raised in aminoglycosides?
decrease dose
What to do if trough levels raised in aminoglycosides?
increase dosing interval
What to do with aminoglycosides monitoring if renally impaired?
increase interval
What to do with aminoglycosides monitoring if severely renally impaired?
decrease dose
Which 6 types of patient groups need therapeutic drug monitoring for amino-glycosides?
Elderly*
Renal impairment
Obesity*
Cystic fibrosis*
High doses
Pregnancy
In amino-glycosides, what 2 factors determine dose?
Weight
Renal function
If post dose peak level of amino-glycosides are too high, what to do?
reduce dose
If pre-dose (trough) levels of amino-glycosides too high what to do?
Increase interval
what to do if patient has renal impairment and is on amino-glycosides?
Increase interval of dosing
what to do if patient has SEVERE renal impairment and is on amino-glycosides?
increase interval + reduce dose
What 2 types of dosing regimens exist in amino-glycosides?
Once daily
Multiple daily
What to do if patient has severe renal impairment <20ml/min + on amino-glycosides once daily regimen?
not give amino-glycosides
What to do if patient has severe renal impairment <20ml/min + on amino-glycosides once daily regimen?
Monitor RI frequent + earlier
monitor after 3-4 doses (change dose)
When is monitoring done for gentamicin and amikacin multiple daily dose regimen?
Done after 3-4 doses
1 hour after dose + just before next dose
Can amino-glycosides be used in pregnancy?
generally NO- risk of auditory or vestibular nerve damage in 2nd/3rd trimester.
Which amino-glycoside has the highest risk in pregnancy if it needed to be given?
streptomycin
What is an MRHA warning related to gentamicin from 2017?
histamine related adverse reactions with some batches
monitor
What are 4 SEs of aminoglycosides? (ONNN)
Ototoxicity
Nephrotoxicity
Neuromuscular
Neuropathy
What patient counselling points can be given for patients on aminoglycosides?
report hearing loss, dizziness, tinnitus.
What main drug class can interact with aminoglycosides to increase ototoxicity?
Loop diuretic- separate dose by long period
What 6 classes of drugs can interact with aminoglycosides to increase nephrotoxicity?
Ciclosporin , tacrolimus, NSAID, MTX, Vancomycin, platins
What 2 other chemo drugs can increase ototoxicity by interacting with aminoglycosides?
Platins
Vinca alkaloids
(vancomycin)
What is MOA of glycopeptides?
active ONLY in gram +ve e.g. MRSA
Blocks cell wall synthesis by preventing cross linking of peptidoglycan chains
Is glycopeptides bactericidal or static?
bactericidal
What are 4 glycopeptides?
- dalbavancin
2 oritavancin
3 teicoplanin
4. vancomycin
What is Dalbavancin used for?
Skin infections
What is oritavancin used for?
Skin infections
What is vancomycin similar to?
Teicoplanin
What glycopeptide has long half life?
Teicoplanin
What is the 4 uses of glycopeptide abx?
Used in C. diff, MRSA - complicated skin + soft tissue, endocarditis
What is route of glycopeptide?
Parenteral
What is therapeutic index of glycopeptides?
10-20mg/L (pre dose)
What patient groups are glycopeptide monitored in?
RI
High dose + long term
Impaired hearing
patients on other ototoxic/ nephrotoxic drugs
Can glycopeptides be used in pregnancy?
NO
What are 4 SEs of glycopeptide? (ROBN)
Red-man syndromme
Ototoxicity
Blood dyscrasias
Nephrotoxicity
What happens upon rapid IV injection of glycopeptides?
cardiogenic shock
anaphylaxis maybe
What is max infusion rate for glycopeptides?
10 mg/mL in fluid restriction but increased risk of infusion-related effects
What 3 things to monitor in patient taking glycopeptide?
Auditory function, renal, FBC
What are 2 interactions that can happen in patient taking glycopeptide?
Ototoxicity + nephrotoxicity
What is spectrum of glycopeptides?
Narrow
How to monitor glycopeptides?
trough concentration
initial doses- body weight
What is optimum trough level of glycopeptides?
15-20mg/L
What is the max cerebrospinal fluid concentration for gentamicin IV/intrathecal injection?
10mg/ L
parenteral treatment of amino-glycosides should NOT exceed —— days?
7 days
What amount should amikacin trough dose not exceed in multiple dosing regime?
pre-dose (‘trough’) concentration should be less than 10 mg/litre.
What amount should amikacin trough dose not exceed in OD dosing regime?
pre-dose (‘trough’) concentration should be less than 5 mg/litre.
