pharmacology lectures Flashcards
what do you prescribe for streptococcal pharyngitis?
penicillin V 500mg qds for 10 days
how do antibiotics work?
antibiotics are molecules that work by binding a target site on bacteria
these target sites are defined as points of biochemical reaction crucial to the survival of the bacterium
the crucial binding site will vary with antibiotic class.
how do penicillins work?
they act on the cell wall of the bacteria and inhibits cell wall synthesis.
what are beta lactams?
penicillins
cephalosorins (cefalexin, cefuroxime, cefotaxime, cerftriaxone)
carbapenems (meropenem, ertapenem)
monobactams (aztreonam)
what types of antibiotics prevent nucleic acid synthesis?
quinolones
rifampin
what antibiotics prevent protein synthesis?
aminoglycosides (gentamicin)
tetracyclines (doxycycline)
Lincosamides (clindamycin)
macrolides (erythromycin, clarithromycin, azithromycin)
what antibiotics inhibit the metabolic pathways?
they do this by inhibiting folate synthesis
sulphonamides - sulphamethoxazole
trimethoprim - co-trimoxazole
what are some gram positive resistant organisms
MRSA - methicillin resistant stahylococcus aureus
VRE - vancomycin resistant enterococci (caused by cephalosporin use)
what causes resistance to certain penicillins?
what has been done to get around this resistance?
the production of beta lactase enzymes which hydrolyse penicillins
we add something that inhibits the beta lactamase eg clavulanate or tazobactam
amoxicillin plus clavulanate = co-amoxiclav
pipericillin plus tazobactam = tazocin
what antibiotics can be used when there is resistance to all other antibiotics?
carbapenems
however there is now also resistance to this
if someone has suspected sepsis what should you prescribe within the hour?
antibiotics
piperacillin/tazobactam and clindamycin
what should you treat group a beta haemolytic streptococcus skin infection with?
benzyl penicillin and clindamycin
what things do you need to consider when deciding if antibiotics are safe for the patient?
intolerance allergy and anaphylaxis side effects age renal and liver function pregnancy and breast feeding drug interaction risk of C.diff
what are cephalosporins good for?
good for people with penicillin allergy
work against some of the penicillin-resistant bacteria
they can get into different parts of the body e.g. meningitis
why are beta-lactams good for gram-positive bacteria?
because gram-positive bacteria have a thick cell wall and beta-lactams inhibit cell wall synthesis
what is the first line agent for cellulitis ?
flucloxacillin
what is the first line for strep throat?
PO penicillin V
IV benzylpenicillin
what is first line for pneumonia?
PO amoxicillin
IV benzylpencillin
what are forms of glycopeptides?
when are they used?
vancomycin
teicoplanin
only used for gram positive bacteria
use in MRSA
can be used in penicillin allergy
have to be used with caution because can cause renal impairment
when would you use a macrolide?
clarithromycin and erythromycin
s. aureus
beta haemolytic strep
atypical pneumonia pathogens (e.g. legionella, mycoplasma)
can be used in penicillin allergy
and in severe pneumonia
they work just as well orally and intravenously
when is it good to use clindamycin?
gram positive
can be used in cellulitis if penicillin allergic
can be used for necrotising fasciitis (turns off nasty towns made by gram positive bugs)
when is it good to use tetracyclines ?
e.g. doxycycline
broad spectrum but mainly for gram positive
can use in cellulitis is penicillin allergy
can be used in chest infections
what type of infections are caused by gram negative bacteria?
UTIs
diarrhoea
intra-abdominal infections
gall bladder infections - billiard sepsis
what is the main draw back of ciprofloxacin?
it can cause C.diff
so tend to avoid in elderly patients
why is ciprofloxacin good and when is it used ?
it gets everywhere in the body - head, bowel, skin
not many bugs are resistant to it
used for gram negative
used in UTI, gall bladder infections, abdominal infections
what is trimethoprim used for?
it is broad spectrum but is mainly used for gram negatives
used in UTIs
when is nitrofurantoin used?
gram negative - UTIs
why are penicillins not good for gram negatives?
because gram negatives produce lots of the enzymes that hydrolyse penicillin
however some beta lactams can be used for gram negatives e.g. cephalosporins
respiratory drug nomenclature
…..mab = monoclonal antibody (reslizumab)
…..sone = corticosteroid (dexamethasone)
…..terol - bronchodilators (salmeterol)
…..lone = corticosteroid (prednisolone)
….nib = kinase inhibitor (nintedanib)
what are inhaled pharmacological and what are mechanisms of administration ?
what are the delivery systems for inhaled drugs?
inhaled medicines are delivered directly to the lung via the oral or nasal route
inhaler devices allow drugs to penetrate deep into the lung and to achieve the correct dose, inhalers deliver dry powder formulation
nebulisers deliver medication in theorem of aerosols
pressurised metered-dose inhalers
spacer devices
dry powder inhalers
nebulisers