Infection Flashcards
What types of antibiotics are safest to use in pregnancy?
Penicillins and cephalosporins
Which antibiotics should be avoided in pregnancy?
Trimethoprim (folate antagonist - teratogenic)
Quinolones
Diaminopyrimidines (eg trimethoprim)
Tetracycline (dental discolouration)
Which is NOT a notifiable disease?
- TB
- Measles
- Food poisoning
- Endocarditis
- Meningitis
Endocarditis
The rest should be notified by drs to the Proper Officer of local authority
Name the aminoglycosides
Gentamicin, amikacin, neomycin, streptomycin, tobramycin
What is the mode of action of aminoglycosides?
Irreversibly bind to ribosomes and inhibit protein synthesis
‘Aminoglycosides have mainly got gram +ve action’
True or false
False - they are active against some gram +ve organisms and many gram -ve
Which condition are aminoglycosides contra-indicated in?
Myasthenia gravis - impair neuromuscular transmission
Which aminoglycoside is NOT given IV?
Neomycin
Rest must be IV as not absorbed by gut
Monitoring for aminoglycosides?
- Renal function - can be nephrotoxic especially in renal impairment
- Auditory function - can cause irreversible ototoxicity
- Serum concentrations esp in elderly/pregnant patients
‘When dosing aminoglycosides for obese patients ideal body weight should ALWAYS be used’
True or false?
True
‘Gentamicin is inactive against anaerobes’
True or false?
True, has good gram -ve activity
When should gentamicin levels be taken in multiple-daily dosing?
- At peak concentration (1 hour post-dose) and levels should be 5-10mg/L
- At trough conc (pre-dose) and levels should be <2mg/L
What are key warning signs for patients taking gentamicin?
- Dehydration
- Ototoxicity
- Nephrotoxicity
Name some antibiotics associated with ototoxicity?
- Aminoglycosides (inc gentamicin)
- Glycopeptides (inc teicoplanin + vancomycin)
How many generations of cephalosporins are there?
5 generations 1st - eg cefalexin 2nd - eg cefuroxime 3rd - eg cefotaxime 4th - eg cefepime 5th - eg ceftobiprole
Some indications for cephalosporins?
UTI, gonorrhoea, pneumonia, meningitis
What is the main side effect of cephalosporins?
Hypersensitivity
0.5-6% of patients with penicillin will also be allergic
c/i in patients with IMMEDIATE HYPERSENSITIVITY to penicillin
How are cephalosporins excreted?
Renally
Reduce doses in renal imp.
Which cephalosporin is poorly absorbed and must be taken with food?
Cefuroxime
‘Carbapenems are narrow spec antibiotics’
True or false?
False - they are broad spectrum
Active against gram +ve, gram -ve and anaerobes
Some indications for carbapenems?
Severe hospital-acquired infections
Complicated UTIs
Why is ertapenem cautioned in epilepsy?
Has seizure-inducing potential and can cause CNS disorders
‘Carbapenems are renally excreted’
True or false?
True
Name some glycopeptides?
Vancomycin, teicoplanin, telavancin
Some indications for glycopeptides?
MRSA, C diff, endocarditis, surgical prophylaxis if high risk of MRSA
Which is NOT a side effect of glycopeptides?
- Steven Johnsons syndrome
- Blood disorders
- Flushing
- Hypertension
- Ototoxicity
HTN
Name contra-indications for glycopeptides?
- Elderly
- History of auditory problems
Which antibiotic is associated with red man syndrome?
Vancomycin
signs - flushing of upper body, angioedema, hypotension
How is serum conc of vancomycin measured?
Trough level on second day of treatment
Should be 10-15mg/L
- also monitor renal + hepatic function, auditory func and blood counts
What are some warning signs for patients on Vancomycin?
- ototoxicity (inc vertigo, dizziness + tinnitus, avoid with other drugs causing this eg loop diuretics, aminoglycosides)
- flushing
- blood disorders (inc sore throat, mouth ulcers, unexplained bleeding)
- nephrotoxicity
- skin disorders
- anaphylaxis + hypotension (if administered too quickly)
What is the minimum rate for a 500g dose of vancomycin?
Not exceed 10mg/min
Which antibiotic should be discontinued IMMEDIATELY if diarrhoea develops?
Clindamycin
Risk of fatal antibiotic-associated colitis
Also C/I in existing diarrhoea
‘Clindamyin is well concentrated in bones and excreted in bile + urine’
True or false
True
Indicated in staphylococcal bone + joint infections
What patient counselling is required for clindamycin?
- Take capsule with a full glass of water
- report any diarrhoea immediately
Why is clindamycin cautioned in middle aged/elderly women?
- colitis can be more common
- especially following surgery
‘Macrolides have a similar action to penicillins’
True or false?
True - and similar spectrum
Often an alternative in penicillin allergy
Which macrolide is most likely to cause GI disturbances?
Erythromycin
Some indications of macrolides?
Respiratory tract infections, chlamydia, skin infections
When are macrolides cautioned?
Conditions that pre-dispose QT prolongation eg, electrolyte disturbances, other drug with risk of QT prolongation
Azithromycin may be sold OTC, for what indications and under what conditions?
Sold for confirmed + asymptomatic chlamydia infection
Single dose of 1g
Over 16 years
Which enzyme do macrolides inhibit?
CYP3A4
Esp clarithromycin + erythromycin
Some drugs that interact with clarithromycin + erythromycin?
- statins - risk of rhabdomylosis
- corticosteroids - risk of cushings syndrome
- CCBs - risk of hypotension/QT prolongation
- carbamazepine
- warfarin - increased anticoagulation
- PPIs - increased gastric pH
- Benzodiazepines - excess CNS depression
Which type of bacteria does metronidazole have a high activity against?
Anaerobic
Some indications of metronidazole?
- anaerobic infections
- oral infections
- leg ulcers
- pressure sores
- H pylori
Which antibiotic is the preferred treatment for tetanus?
Metronidazole
Why is metronidazole not recommended in breast feeding?
Can give milk a bitter taste