penicillins

Question 1

PMP 4 interactions - vit K antagonists + methotrexate

Answer 1

• aconocoumarol: PMP potentially alters AC effect, monitor and adjust dose
• MTX: PMP predicted to increase risk of toxicity. monitor
• pheninidione: PMP may increase risk of bleeding events
• warfarin: PMP potentially alters AC effect of warfarin, monitor INR and adjust dose

Question 2

name the 4 drugs that PMP interacts with

Answer 2

vit K antagonists - warfarin, acenocoumarol, pheninidione
MTX

Question 3

PMP - take with or without food

Answer 3

Take this medicine when your stomach is empty. This means an hour before food or 2 hours after food

Question 4

MOA Penicillins

Answer 4

bactericidal
act by inferring with bacterial cell wall synthesis

Question 5

can you use penicillin in CNS infections

Answer 5

penetration into CSF if poor except with meninges are inflamed

Question 6

important safety info - fluclox & hepatic disorders

Answer 6

cholestatic jaundice and hepatitis may occur rarely up to 2 months after treatment with fluclox has stopped
RF: admin for more than 2 weeks and increasing age
do not use in pt with Hx hepatic dysfunction associated with fluclox
use in caution in HI
careful enquiry should be made about hypersensitivity reactions to Beta lactam abx

Question 7

can cholestatic jaundice and hepatitis occur even after fluclox has been stopped?

Answer 7

can occur up to two months after treatment with fluclox has been stopped

Question 8

name 2 risk factors for choelstatic jaundice and hepatitis with fluclox

Answer 8

taking for more than 2 weeks
increasing age

Question 9

what is the interaction between paracetamol and fluclox

Answer 9

caution
P has been reported to cause high anion gap metabolic acidosis when given with F

Question 10

what are the 5 severe interactions with fluclox?

Answer 10

vit K antagonists - warfarin, pheninidone, acecoumarol (rosa of bleeding events/altered AC effect)
MTX (risk of toxicity, monitor)
paracetamol (caution, high anion gap metabolic acidosis)

Question 11

the following electrolyte imbalance can occur with fluxloc, esp in high doses

Answer 11

potentially life threatening hypokalaemia - can be resistant to potassium supplementation ! hence regular monitoring of serum potassium recommended when using higher doses

Question 12

diarrhoea frequently occurs during oral penicillin therapy. it is most common with …….

Answer 12

most common with BS penicillins, which can cause abx-associated colitis

Question 13

who is at higher risk of anaphylactic reactions to penicillins

Answer 13

history of atopic allergy e.g. asthma, eczema, hay fever

Question 14

patients with history of anaphylaxis, urticaria, or rash immediately after penicillin administration - should they be given a penicillin

Answer 14

no because at risk of immediate hypersensitivity

Question 15

which characteristics indicate immediate hypersensitivity to penicillin

Answer 15

history of anaphylaxis, urticaria or rash immediately after penicillin

Question 16

individuals with a history of a minor rash (non-confluent, non-pruritic rash restricted to small area of body) or rash that occurs >72h after penicillin administration - should they be given penicillin

Answer 16

probably not allergic
do not withhold unnecessarily for serious infections
however bear in mind the possibility of an allergic reaction
other beta-lactam abx including cephalosporins can be used too

Question 17

dose of pivmecillinam for acute uncomplicated cystitis

Answer 17

initially 400mg for 1 dose
then 200mg every 8 hours (TDS) for 8 tablets
total 10 tabs
(for body weight 40kg and above)

Question 18

when pivmecillinam is used orally, it must only be used in pt with the following body weight

Answer 18

40kg and above

Question 19

what are the 5 interactions of pivmecillinam

Answer 19

• vit k antagonists (warfarin, acecoumarol, phenindione - increased risk bleeding events/increased AC effect, monitor INR)
• valproate - avoid increased risk of adverse effects
• MTX - increased toxicity , monitor

Question 20

pivmecillinam - directions for administration

Answer 20

• swallow whole with plenty of water during meals while sitting or standing

Question 21

labels for pivmecillinam

Answer 21

take with or just after food, or a meal
take with a full glass of water

Question 22

this route of administration is not recommended for benzylpenicillin sodium

Answer 22

intrathecal

Question 23

are benzyl penicillin sodium and benzathine benzylpenicillin the same

Answer 23

BS is a short acting form of B and is not interchangeable with BB

Question 24

6 common side effects for all penicillins

Answer 24

• diarrhoea
• thrombocytopenia
• hypersensitivity
• nausea
• vomiting
• skin reactions

Question 25

contraindications for coamoxiclav (2)

Answer 25

• hx of co-amoxiclav associated jaundice or hepatic dysfunction
• hx penicillin-associated jaundice or hepatic dysfunction