macrolides

Question 1

dose of clarithromcyin in CAP

Answer 1

500mg BD for 5 days

Question 2

dose of clarithromcyin in HAP

Answer 2

500mg BD for 5 days then review

Question 3

dose of clarithromycin in acute exacerbation of COPD

Answer 3

500mg BD for 5 days

Question 4

caution for all macrolides (IV and oral)

Answer 4

• electrolyte disturbances - predisposition to QT interval prolongation
• may aggravate MG
• predisposition to QT interval prolongation

Question 5

common SE

Answer 5

• appetite decreased
• d,n,v
• GI discomfort
• dizzy
• headache
• hearing impairment
• insomnia
• nausea
• skin reactions
• vision disorders

Question 6

clarithromcyin is a inhibitor or inducer? what does this mean

Answer 6

inhibitor
this means it increases the exposure of drugs that are normally metabolised by CYP enzymes, which can lead to toxicity

Question 7

azithromycin interactions with warfarin, acenocoumarol, pheninidone

Answer 7

increases risk of bleeding events
monitor

Question 8

azithromycin interaction with colchicine

Answer 8

predicted to increase exposure to colchicine
avoid or adjust colchicine dose to half

Question 9

azithromycin interaction with chloroquine

Answer 9

Azith might increase risk of serious CV adverse effects when given with this, MHRA advised caution

Question 10

azithromycin interaction with DOACs

Answer 10

predicted to increase exposure to DOACs

Question 11

azithromycin interaction with digoxin

Answer 11

increases conc of digoxin, monitor

Question 12

azithromycin interactions with theophylline

Answer 12

predicted to increase exposure
adjust dose

Question 13

a script comes in for a prescription for azithromycin. the pt also regularly takes a statin. what do you do

Answer 13

no interaction so just dispense as normal

Question 14

a script comes in for clarithromcyin. the pt also regularly takes a statin. what do you do

Answer 14

tell pt to stop statin while taking abx as there is increased risk of rhabdomyolysis

Question 15

macrolides and colchicine interaction

Answer 15

macrolides increase the exposure to colchicine
avoid or adjust colchicine dose

Question 16

a script comes in for clarithromcyin for a pt with type one diabetes. what do you do

Answer 16

clarithromcyin reported to cause hypo when given with insulin
monitor BG

Question 17

use of clarithromcyin in pregnancy

Answer 17

avoid unless potential benefit outweighs risk esp in 1st trimester

Question 18

important safety info with erythromycin - MHRA (cardiac risks)

Answer 18

• QT interval prolongation
• do not give in pt with Hx QT interval prolongation or ventricular arrhythmias (including TDP), or in pt with electrolyte disturbances

Question 19

MHRA important safety info with rivaroxban and erythromycin

Answer 19

increased risk of bleeding
caution

Question 20

should erythromycin be prescribed to a pt taking rivaroxaban

Answer 20

can be but with caution as increased risk of bleeding

Question 21

erythromycin MHRA advice - infantile hypertrophic pyloric stenosis associated with use of erythromycin in infants

Answer 21

• this is then there is abnormal thickening of the pyloric muscles in the stomach leading to gastric outlet obstruction
• 2-3 fold increase in risk after exposure to erythromycin during infancy
• risk highest in first 14 days after birth
• seek medical attention if vomiting or irritability with feeding occurs in infants during treatment
• benefit-risk balance of precribing in infants

Question 22

which abx holds a 2-3 fold increase in the risk of infantile hypertrophic pyloric stenosis after exposure of the abx during infancy? - azithromycin, clarithromcyin, erythromycin, doxycycline, co-amoxiclav

Answer 22

erythromycin

Question 23

erythromcyin is an enzyme…. and what does this mean

Answer 23

inhibtior
this means it leads to increased levels of drugs that are normally metabolised by CYP enzymes, which can lead to toxicity

Question 24

what is in common with the following drugs amiodarone, sotalol, domperidone, fluconazole and amisulpride
and what do you need to consider if prescribing macrolides to these pt

Answer 24

they prolong QT interval, as do erythromycin and clarithromcyin
- this increases risk of TDP

Question 25

which statin is not associated with CYP interactions?

Answer 25

rosuvastatin

Question 26

a pt who is on carbamazepine has been given clarithromcyin for an infection. what do you do

Answer 26

clarithromcyin can increase carb levels, causing toxicity (nav, ataxia, drowsiness)
monitor carb levels within 3-5 days of starting abx and adjust dose

Question 27

clarithromcyin and RI

Answer 27

if EGFR is below 30 do not use MR preps

Question 28

azithromycin dose for uncomplicated gonorrhoea

Answer 28

2g for one dose

Question 29

azithromcyin dose for uncomplicated genital chlamydia, uncomplicated non-gonococcal urethritis

Answer 29

take 1g once daily for 1 day then 500mg once daily for 2 days

Question 30

erythromycin GR tabs labelling requirements (apart from space doses evenly, keep taking until course finished) - 2

Answer 30

do not take indigestion remedies 2 h before or after
swallow whole, do not chew or crush

Question 31

azithromycin labelling requirements (apart from space dose evenly, keep taking until course finished) - 1 (+1 for capsules)

Answer 31

do not take indigestion remedies 2h before or after
CAPSULES : take on empty stomach - 1 hour before or 2 hours after food

Question 32

which form of azithromycin needs to be taken on empty stomach (1h before or 2h after food)

Answer 32

azith capsules only

Question 33

With form of clarithromycin needs to be taken with or after food

Answer 33

clarithromycin MR

Question 34

broad or narrow spectrum?

Answer 34

broad

Question 35

bacteriostatic or bactericidal?

Answer 35

bacteriostatic - prevents bacterial growth

Question 36

MOA

Answer 36

inhibit the growth of bacteria by binding to the 50S ribosomal subunit of bacterial cells and preventing protein synthesis

bacteriostatic