Aani Micro: Drugs- Antivirals and Antimicrobials Flashcards
How does acyclovir work?
Guanosine analogue - blocks viral thymidine kinase
How to treat CMV?
- ganciclovir (nucleoside analogue)
- foscarnet
- cidofovir
Why does acyclovir not work for CMV?
It doesnt have thymidine kinase enzyme
How to treat HSV?
Act Very Fast
Acyclovir
Valacyclovir
Famcyclovir
Sideeffect of Ganciclovir?
Bone marrow toxicity
How high should HBV levels be before you treat the patient?
> 2000 HBV DNA serum levels
What is Palivizumab used for?
RSV
What can treat RSV?
Palivizumab
OR
Ribavirin (guanosine analogue)
How to treat Hep C?
Peg IFN Alpha
Or
Ribavarin
Which types of Hep C are most successfully treated?
Genotypes 2 and 3
Which types of Hep C are least successfully treated?
Genotypes 1 ,4,5 and 6
Sideeffect of Ribavarin?
Haemolytic Anaemia
Name some influenza neuraminidase inhibitors
Oseltamivir, Zanamivir and Sialic Acid
Name an influenza drug that isnt a neuraminidase inhibitor- what does it do?
Amantidine - blocks M2 ion channel
MAN
M2
Why is the risk of getting CMV higher in BM transplant if the pt already has CMV (seropositive)?
So basically the recipient is seropositive so already has CMV.
The recipient can control it but is getting BM transplant so losing their protective Abs. Because the donor is seronegative they don’t have protective Abs against CMV so the recipient doesnt get new ones and so they contract CMV.
If the donor was seropositive they’d likely be also donating protective Abs!
Name the types of antimicrobials
- Cell wall synthesis inhibitors
- Protein synthesis inhibitors
- DNA synthesis inhibitors
- RNA synthesis inhibitors
- Cell membrane toxins
- Folate inhibitors
What are the cell wall synthesis inhibitor groups and how do they work?
B lactams and Glycopeptides
B lactams inactivate transpeptidase enzymes that are needed for peptide cross links in the cell wall.
Glycopeptides inhibit transglycosidase enzymes
Name the B lactams
PEN CAR SEF MON Penicillins Carbapenems Cephalosporins Monobactams
What are the penicillins and talk about each key feature
In general the penicillins have good aerobic and anaerobic cover.
Penicillin - gram +. broken down by B lactamases
Amoxicillin - broad spec gram + and -. Also broken down by B lactamases.
Clavulanic acid - add to amoxicilin to protect against B lactamased = augmentin.
Flucloxacilin - Less active but resistant to B lactamases.
Piperacilin - Same as amoxicilin but with pseudomonas cover too
What are the Carbapenems?
Meropenem and ertapenem
Stable to extended spectrum B lactamases but worried about carbapenemase enzymes building resistance.
What are the Cephalosporins?
In general they are good for Gram - and cover pseudomomas. Cephtriaxone - for meningitis Cefuroxime Ceftazidime BUT B lactamases are resistant to these AND you need to add metronidazole for anaerobic cover
What are the positives and negatives about B lactam antibiotics?
+ Not v toxic
+ Can cross inflamed meninges
- Renally excreted
- Cross allergenic - anaphylaxis
- Short half life
What are the glycopeptides?
Vancomycin and Teicoplanin
what the glycoPLANIN on TV
Benefits of glycopeptides?
Gram + cover
Good for MRSA as resistant to B lactamases
Negatives of glycopeptides?
- Only work against gram + cos too big to get through outer cell wall of gram -
- Nephrotoxic
- Slow
What are the Protein Synthesis inhibitor antimicrobial drugs?
ATM CO Aminoglycosides Tetracyclins Macrolides Chloramphenicol Oxazolidinones
Which ribosomal subunit to the Protein synthesis inhibitors each bind to?
Aminoglycosides - 30s Tetracyclines - 30s Macrolides - 50s Chloramphenicol - 50s Oxazolidinones -23s of 50s to prevent 70s
Side effect of chloramphenicoles?
Grey baby syndrome and risk of aplastic anaemia
What is chloramphenicole used for?
Eye drops
What are the macrolides?
Erythromyciin/Clarithro/azithromycin
What are the macrolides used for?
Intracellular organisms such as campylobacter and legionella
What is a common tetracycline?
Doxycyclin
What is doxycyclin used for?
Broad spec against intracellular pathogens e.g. Chlamydia and mycoplasma and Rikettsia
What are the inhibitors of DNA synthesis antimicrobials?
Nitroimidazoles e.g. metronidazole
And Quinolones e.g. Ciproflox - all the FLOX.
What are the Nitroimidazoles used for?
Good anearobic cover and against protozoa e.g. giarda
What are the RNA synthesis inhibitor antimicrobials?
Rifamycins e.g. Rifampicin and Rifabutin
How do RNA inhibitors work?
Bind to the DNA dependent RNA polymerase
How do we use the RNA synthesis inhibitors?
NEVER alone as they develop resistance quickly. used for mycobacteria
S/E of RNA synthesis inhibitors?
Orange secretions
What are the cell membrane toxin antimicrobials?
Daptomycin and Colistin
Dapto for gram + and colistin for gram -
When can you not used daptomycin?
Pneumonia- it is broken down by lung surfactant
What are the inhibitors of folate metabolism? Give an example each and how they’re used.
Sulphonamides e.g. sulfamethoxazole and Diaminopyrimidines e.g. trimethoprim.
They are both combined to treat PCP
How do you treat community vs hospital acquired UTIs?
Community- trimethoprim x 3
Hospital - Co-amoxiclav (augmentin)
How to treat mild community acquired pneumonia?
Amoxicililin (Penicillin B lactam)
How to treat severe community acquired pneumonia?
Cefuroxime (cephalosporin B lactam) AND clarithromycin (Macrolide- protein synthesis inhibitor)
How to treat hospital acquired pneumonia?
Cefuroxime (cehalosporin B lactam)
Which skin pathogen is most common?
Staph Aureus
How to treat Staph A skin infections?
Flucloxacillin (a norrow spec penicillin B lactam)
Which organism causes Bacterial meningitis?
Meningiococcus/streptococcus
How to treat bacterial meningitis in adults?
cafriaxone - think you want to shop the treee down if you have meningitis TREE-AXE.
Ceftriaxone IV 2g bd
Give amoxicillin instead if immunocompromised
How to treat someone who has meningitis with encephalitis?
Cetfriaxone 2g bd AND acyclovir 10mg/kg tds
How to treat C.Diff?
Metronidazole (stop offending Abx e.g. ceph)
How to treat severe sepsis?
Cefuroxime, metronidazole and gentamicin
How to treat neutropaenic sepsis?
Tazocin and gentamycin
How to treat B haemolytic strep?
Benzylpenicillin
Which organisms cause early onset sepsis in babies?
Group B strep
E.Coli
Listeria
How to treat meningitis in kids?
<3 months : Cefotaxime AND amoxicillin - babies a taxing amo
3 months - 5 years: Caftriaxone
6 years +: Cefrtriaxone + Clarithromycin
Which organisms cause meningitis in kids?
N.meningitidis all ages
Strep Pneumonia all ages esp < 2 years
HIB <3 months
