Penicillin Flashcards
what drug class is penicillin?
beta lactam
how does penicillin kill bacteria?
interferes w/ cell wall synthesis
spectrum of activity?
narrow
what bacteria does penicillin target?
mostly gram positive cocci
also:
gram negative bacilli
some negative cocci
potentially anarobes - fuso spp, clostridium, anarobic strep
what does killing of bacteria depend on?
time - takes time for inhibition process and eventual rupture of microorganism
name 3 penicillin preparations
Pen G - benzylpenicillin (IV)
Pen V - phenoxymethylpenicillin (oral)
Procaine/benzathine penicillin
how are the 3 preparations delivered?
pen G = IV form, destroyed by gastric acid
pen V = oral form, gastric acid stable
procaine/benzathine = IM form, named pt basis only
when is pen G indicated?
Pen G is reserved for severe infection or if oral route comprimised i.e. malabsorption, vomiting
what % of population will have a penicillin reaction?
8%
symptoms of penicillin reaction
maculopapular or urticarial rash
most likely age group for penicillin reaction
20-49yrs
fatal reactions more likely in elderly
list symptoms of immediate penicillin reaction
nausea/vomiting
prutisis
erythema, urticaria, rash
wheeze
laryngeal oedema
angioedema
bronchospasm
hypotension
CV collapse
list symptoms of delayed penicillin reaction
rash:
vesicular
maculopapular
bullous
urticarial
scarlatiniform
blood dyscrasias
haemolytic anaemia
leukopenia
thrombocytopenia
aplastic anaemia
should penicillin use be avoided when previous reaction?
not if minor delayed reaction - as are short lived and do not show long lasting penicillin hypersensitivity
list obscure autoimmune conditions that can occur from penicillin adverse reaction
Eosinophilia
Steven johnson syndrome
Exfoliative dermatitis
DRESS syndrome
list risk factors for penicillin reaction
multiple drug allergies
atopic disease - sensitive to allergens
asthma
allergic rhinitis - inflamm. of the inner nose
nasal polyps
how much more likely is hypersensitivity to penicillin when re-exposure compared to negative history?
4-6x greater
what should be filled out when an ADR occurs?
yellow card
provides early warning that the safety of a product may require investigation
pen V dose
500mg every 6hrs (4x a day)
pen v course
over 3-5 days
pen v administration
oral
pen v loading dose?
yes
pen v fasting required?
yes
pen g dose
1.2g every 6hrs
