What penicillin is used for gram positive?
Benzyl Penicillin
What penicillin is used for gram negative?
Amoxicillin
What penicillin is used for beta-lactamase producing coliforms?
Co-amoxiclav
What penicillin is used for staph infections?
Flucloxacillin
What penicillin is used for extended gram negative cover?
Piperacillin
What penicillin is used for all active bacteria?
imipenem
What do cephalosporins work against?
Gram negative
What decrease gram positive activity?
Proportionally through first to third generation drugs.
What is the cheapest and most common aminoglycoside?
Gentamicin
What must be monitored when using gentamicin?
Serum levels because of toxicity.
What must be monitored when using glycopeptides?
Vancomycin levels as toxic.
What do quinolones provide the only oral therapy for?
Pseudomonas infections
Quinolones against strep is good/bad.
Bad
What is metronidazole effective against?
Anaerobes (Positive and negative).
What is fusidic acid used for?
Anti-staph
What is the thing to ensure doesn’t happen when using trimethoprim?
That it does not predispose to C.Diff
What do tetracyclines inhibit?
Bacterial protein synthesis.
Where are tetracyclines deposited?
Teeth and bones
What type of antibiotics are clindamycin?
Lincosamide
What do clindamycin work against?
Gram postive
What new agent has activity against MRSA?
Linezolid
What can linezolid cause?
Bone marrow suppression
What new agent has activity against gram positive organisms?
Daptomycin
What new agent is active against C.Diff?
Fidaxomicin
What two agents are there for UTIs?
Nalidixic acid
Nitrofurantoin
What are antimicrobials associated with?
Adverse reactions
Approx. __% of hospitalised patients will develop adverse reactions to antimicrobials.
5
What are most adverse reactions upon withdrawal of antimicrobial?
Reversible
What are the 3 allergic reactions?
Immediate hypersensitivity
Delayed hypersensitivity
GI side effects
Immediate hypersensitivity is Ig_ mediated.
E
What is a common sign of delayed hypersensitivity?
Skin rash
What is Stevens-Johnson syndrome related to?
Sulphonamides
What are common side effects associated with GI?
Vomiting
Nausea
What is associated with toxin production by C.Diff?
Diarrhoea
How does C.Diff produce toxins?
Overgrow normal flora during antibiotic therapy.
How is C.Diff diagnosed?
Toxins in stool sample. Use enzyme immunoassay.
What causes thrush?
Candida albicans
What can happen to the liver?
Elevation of liver enzymes
Severe hepatitis
Where are all the drugs metabolised?
Liver
What is the most important route of drug excretion?
Kidney
What is dose related and common in patients with preexisting renal disease?
Nephrotoxicity
When does ototoxicity occur?
Following aminoglycoside or vancomycin use
What causes optic neuropathy?
Ethambutol
What causes encephalopathy and convulsions?
High dose penicillin, especially if dose isn’t reduced.
What causes peripheral neuropathy?
Metronidazole
What are the 2 things haematological toxicity can cause?
Toxic effect on bone marrow resulting in selective depression of one cell line
Unselective depression of all bone marrow elements.
How do co-trimoxazole act?
Competitive inhibition
How can we minimise adverse reactions?
Only use antimicrobials when indicated, with the minimum dose and duration necessary.
Who needs to be treated carefully in prescription?
Extremes of age
Pregnant
Liver/renal insufficiency
What must the therapeutic margin be?
Low
Where should adverse reactions be reported?
Committee on safety of medicines.
Define prophylaxis.
Administration of antimicrobials to prevent the future occurrence of infection.
What can mutagenic antimicrobials do to foetus?
Induce mutation
What can teratogenic antimicrobials cause?
Congenital abnormalities.
What type of operation would prophylaxis be used for?
Abdominal
What might have to happen if the organism causing infection is unknown?
Antimicrobial therapy
What should be taken into account in therapy?
Site of infection
Type of infection
Why may you have to use combined antimicrobials?
To cover mixed infection
Two have an enhanced effect
Minimise development of resistant strains
What are the 3 outcomes of using combination antimicrobials?
Additive
Antagonistic
Synergistic
Combination of two cidal drugs or two static drugs is…
Additive
Synergistic
Combination of one static and one cidal drug is…
Antagonism
What is of little use in clinical practice?
Antimicrobial which is unable to penetrate the site of infection.
Gentamicin and vancomycin have ______ therapeutic index.
Low
The difference between a therapeutic and toxic dose is small/large.
Small
What are the considerations of dose and duration of therapy?
Seriousness of infection Expert opinion Age/liver or renal failure Time Intravenous therapy
Who gives advice on urgent treatment?
Medical microbiologists
What are the 2 reasons for monitoring serum levels?
Ensure therapeutic levels are achieved
Ensure levels are not high enough to be toxic.
What is the simplest way to measure MIC?
E-test
What is an E-test?
Paper strip with gradient of antibiotic conc.
MIC can be read where organism growth intersects the strip.
In vitro lab tests only give a ______
Prediction
What factors influence outcome of E-test?
Route of admin
Dosing schedule
Penetration
Interactions with other drugs