macrolides Flashcards
dose of clarithromcyin in CAP
500mg BD for 5 days
dose of clarithromcyin in HAP
500mg BD for 5 days then review
dose of clarithromycin in acute exacerbation of COPD
500mg BD for 5 days
caution for all macrolides (IV and oral)
- electrolyte disturbances - predisposition to QT interval prolongation
- may aggravate MG
- predisposition to QT interval prolongation
common SE
- appetite decreased
- d,n,v
- GI discomfort
- dizzy
- headache
- hearing impairment
- insomnia
- nausea
- skin reactions
- vision disorders
clarithromcyin is a inhibitor or inducer? what does this mean
inhibitor
this means it increases the exposure of drugs that are normally metabolised by CYP enzymes, which can lead to toxicity
azithromycin interactions with warfarin, acenocoumarol, pheninidone
increases risk of bleeding events
monitor
azithromycin interaction with colchicine
predicted to increase exposure to colchicine
avoid or adjust colchicine dose to half
azithromycin interaction with chloroquine
Azith might increase risk of serious CV adverse effects when given with this, MHRA advised caution
azithromycin interaction with DOACs
predicted to increase exposure to DOACs
azithromycin interaction with digoxin
increases conc of digoxin, monitor
azithromycin interactions with theophylline
predicted to increase exposure
adjust dose
a script comes in for a prescription for azithromycin. the pt also regularly takes a statin. what do you do
no interaction so just dispense as normal
a script comes in for clarithromcyin. the pt also regularly takes a statin. what do you do
tell pt to stop statin while taking abx as there is increased risk of rhabdomyolysis
macrolides and colchicine interaction
macrolides increase the exposure to colchicine
avoid or adjust colchicine dose
a script comes in for clarithromcyin for a pt with type one diabetes. what do you do
clarithromcyin reported to cause hypo when given with insulin
monitor BG
use of clarithromcyin in pregnancy
avoid unless potential benefit outweighs risk esp in 1st trimester
important safety info with erythromycin - MHRA (cardiac risks)
- QT interval prolongation
- do not give in pt with Hx QT interval prolongation or ventricular arrhythmias (including TDP), or in pt with electrolyte disturbances
MHRA important safety info with rivaroxban and erythromycin
increased risk of bleeding
caution
should erythromycin be prescribed to a pt taking rivaroxaban
can be but with caution as increased risk of bleeding
erythromycin MHRA advice - infantile hypertrophic pyloric stenosis associated with use of erythromycin in infants
- 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
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
erythromycin
erythromcyin is an enzyme…. and what does this mean
inhibtior
this means it leads to increased levels of drugs that are normally metabolised by CYP enzymes, which can lead to toxicity
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
they prolong QT interval, as do erythromycin and clarithromcyin
- this increases risk of TDP
which statin is not associated with CYP interactions?
rosuvastatin
a pt who is on carbamazepine has been given clarithromcyin for an infection. what do you do
clarithromcyin can increase carb levels, causing toxicity (nav, ataxia, drowsiness)
monitor carb levels within 3-5 days of starting abx and adjust dose
clarithromcyin and RI
if EGFR is below 30 do not use MR preps
azithromycin dose for uncomplicated gonorrhoea
2g for one dose
azithromcyin dose for uncomplicated genital chlamydia, uncomplicated non-gonococcal urethritis
take 1g once daily for 1 day then 500mg once daily for 2 days
erythromycin GR tabs labelling requirements (apart from space doses evenly, keep taking until course finished) - 2
do not take indigestion remedies 2 h before or after
swallow whole, do not chew or crush
azithromycin labelling requirements (apart from space dose evenly, keep taking until course finished) - 1 (+1 for capsules)
do not take indigestion remedies 2h before or after
CAPSULES : take on empty stomach - 1 hour before or 2 hours after food
which form of azithromycin needs to be taken on empty stomach (1h before or 2h after food)
azith capsules only
With form of clarithromycin needs to be taken with or after food
clarithromycin MR
broad or narrow spectrum?
broad
bacteriostatic or bactericidal?
bacteriostatic - prevents bacterial growth
MOA
inhibit the growth of bacteria by binding to the 50S ribosomal subunit of bacterial cells and preventing protein synthesis
bacteriostatic
