UTIs

Question 1

What is the mechanism of action of aminoglycosides?

Answer 1

bind to 30S ribosomal sub-unit causing:

• misreading of mRNA codon, leading to aa sequence errors
• disrupt polysomes thus reducing efficiency fo protein synthesis
• inhibit translocation of tRNA between A and P ribosomal binding sites

Question 2

Name some adverse effects of gnetamicin

Answer 2

damage to cochlear and vestibular apparatus - loss of balance, tinnitus, loss of hearing.
may cause renal damage.
may cause allergic reactions.

Question 3

gentamicin is excreted unmodified byt eh kidneys so it follows “first order kinetics”. what does this mean?

Answer 3

that the drug is cleared from teh blood at a rate proportional to its concentration. So, after a dose, the level in the blood decays exponentially

Question 4

name the 2 types of dosing regimens used in the UK when prescribing gentamicin

Answer 4

• parmacokinetic

- extended interval dosing (may also be known as ‘once daily dosing’ or ‘Hartford dosing’)

Question 5

what are the first choices of antibiotic for a lower UTI in non-pregnant women aged 16yrs and over?

Answer 5

nitrofurantoin (if eGFR >45)

Trimethoprim (if low risk of resistance)

Question 6

what is the choice of antibiotic in pregnant women aged 12yrs and over

Answer 6

nitrofurantoin

Question 7

Name some first choice abx for acute pyelonephritis for non-pregnant women and men aged 16yrs and over

Answer 7

cefalexin (cephalosporin)
co-amoxiclav
trimethoprim (only if culture results available and susceptible)
ciprofloxacin