Infections Flashcards
What parameters require monitoring when using aminogylcosides?
Drug-serum concentration and renal function
When should you avoid using once daily dose regimen of aminoglycosides?
Avoid in renal function <20ml/min
HACEK or gram-positive endocarditis
Burns covering >20% of body
When should blood samples be taken for multiple dosing regimen of aminoglycosides?
Post-dose (peak) concentrations 1 hour after administration
Pre-dose (trough) concentrations before administration of next dose
How to manage high post-dose serum concentration of aminoglycosides
Reduce dose
How to manage high pre-dose serum concentration of aminoglycosides
Increase interval
\Which classes of abx contain beta-lactam structure?
Pencillins
Carbapenems
Cephalosporins
Which antibiotics inhibit cell wall synthesis ?
Pencillins
Carbapenems
Cephalosporins
Glycopeptides
Give three examples of cephalosporins
Cefalexin (first-gen)
Cefuroxime (second-gen)
Cefotaxime, ceftazidime, ceftriaxone (third gen)
What is the MOA of macrolides?
Inhibit bacterial protein synthesis
Metronidazole is active against __________ bacteria
Metronidazole is active against anaerobic bacteria
Which abx should be taken on an empty stomach?
Flucloxacillin
Isoniazid
Phenoxymethylpenicillin
Ampicillin
Which abx should be taken with or just after food?
Metronidazole
Nitrofurantoin
What is the interaction between metronidazole and alcohol
Disulfram-like reaction causing flushing, SOB, throbbing headache
Avoid __________ during the course of metrondiazole and for _________ after ____________________________
Avoid alcohol during the course of metrondiazole and for 48 hours after completing the course.
Vancomycin has ____ gram __________ activity.
Vancomycin has no gram negative activity.
What class of abx can cross-react with pencillins?
First generation cephalosporins and early second generation of cephalosporins
Give examples of aminoglycosides and how are they used?
Gentamicin, amikacin, streptomycin
Poorly absorbed from the gut therefore given by injection for systemic infections (requires TDM) - except neomycin which is never given parenterally (too toxic)
How do you measure serum gentamicin concentrations?
After 3 or 4 doses of a multiple daily dose regimen, blood sample taken 1 hour after dose (peak) and just before dose (trough).
Measure serum-gentamicin conc at least every 3 days thereafter and after a dose change. More frequently in renal impairment.
What are the target concentrations of gentamicin in multiple daily dose regimens?
peak concentration should 5-10mg/L
trough concentrations should be less than 2mg/L
Same targets for children.
What are the target concentrations of gentamicin in endocarditis?
peak = 3-5mg/L
trough= less than 1mg/L
Same targets for children.
What are the contra-indications of all aminoglycosides ?
Myasthenia gravis (aminoglycosides may impair neuromuscular transmission)
MHRA/CHM advice around aminoglycosides..
increased risk of deafness in patients with mitochoncrial mutations.
Deafness, tinnitus, vertigo, vestibular disorders should be reported
Vancomycin and teicoplanin belong to which class of abx?
Glycopeptides
What types of symptoms may develop in patients using flucloxacillin?
Hepatic disorders - cholestatic jaundice and hepatitis can occur upto 2 months post treatment.
Which antibiotic has highest risk of antibiotic associated colitis?
Clindamycin (lincosamide) - patients should be advised to discontinue and contact doctor immediately if severe, prolonged or bloody diarrhoea develops.
What are TDM requirments of vancomycin?
All patients require serum-vancomycin measurement on second day of treatment.
measure pre-dose concentrations (trough)
target usually 10-20mg/L
Vancomycin is __________ absorbed from GIT.
Vancomycin is poorly absorbed from GIT.
Should only be given orally for treatment of C.diff infections.
What is first line for lower UTIs in men, women and pregnant-women?
Nitrofurantoin can be used in all pts (3 days for non-pregnant women, 7 days in pregnant women and men)
Trimethoprim as first line in men (7 days) and non-pregnant women (3 days). Avoid in pregnant women (teratogenic in first trimester
What are the renal impairment requirments for nitrofurantoin?
Avoid if eGFR less than 45 mL/ minute/1.73 m2. May be used with caution if eGFR 30–44, as a short-course only (3 to 7 days), to treat uncomplicated lower urinary-tract infection
MHRA/CHM advice with nitrofurantoin…
In adults and children, reminder of risks of pulmonary and hepatic adverse drug reactions.
Monitor patients for respiratory symptoms, hepatitis or liver injury in first week of treatment and if on long-term therapy
Which medications can be used for prophylaxis of recurrent UTIs
Nitrofurantoin 50-100mg ON
Trimethoprim 100mg ON
When are UTIs considered recurrent?
After at least TWO episodes within 6 months or,
THREE or more episodes within 12 months.
What is the initial empirical therapy of meningitis?
Which drugs sould be used in there are allergies to penicillins?
Benzylpenicillin (IV or IM injection)
Cefotaxime or chloramphenicol if immediate hypersensitivity to cepaholsporins or penicillins
Which abx are most associated with c.diff infections?
Clindamycin
Cephalosporins (3rd ad 4th gen)
Fluoroquinolones
Broad-spectrum penicillins
PPIs can also increase risk
What are the restrictions around using nitrofurantoin in pregnant women?
Avoid at term (36-42 weeks of pregnancy)
Which are some contraindications of nitrofurantoin?
G6PD deficiency, infants less than 3 months
What are common side effects of fluoroquinolones?
QT interval prolongation, vision disorders, sleep disorders, tinnitus, fungal infections
What MHRA alerts are associated with quinolones?
Induce convulsions (taking NSAIDs at the same time may also induce them)
Tendon damage - risk is increased with concomitant use of corticosteroids
Risk of aortic aneurysm - seek immediate medical attention if sudden-onset of severe abdominal, chest or back pain
Suicidal thoughts and behaviours
Must only be prescribed if other comonly recommended abx inappropriate
What MHRA alerts are associated with aminoglycosides?
increased risk of deafness in patients with mitochondrial mutations
What topical treatments are available for impetigo and when should you use them?
hydrogen peroxide 1% cream (OTC) - can be used for localized non-bullous impetigo, when patient is not systemically unwell. Not if impetigo near eyes or intranasal areas. For children over 6 months and adults.
fusidic acid 2% cream (POM) - can be used for widespread impetigo when patient is not systemically unwell (alternatively mupirocin 2% if fusidic acid resistance suspected)
All topical treatment duration for 5 days.
When can doxycycline be used in children?
When no other suitable antibiotic is available.
For a severe or life-threatening condition (e.g. Rocky Mountain spotted fever)
What are the effects of tetracyclines in pregnancy?
What advise should be given to women about breastfeeding?
Effects on skeletal development.
Discoloration of the child’s teeth
Maternal hepatotoxicity has been reported with large parenteral doses.
AVOID in breastfeeding.
What ages of patients can be treated for otitis media under Pharmacy First?
children from 1 to under 18s
When should you prescribe oral antibiotics for otitis media and which one?
bilateral otitis media for children under 2, where symptoms have lasted more than 3 days.
ottorhea from perforated ear drum in older children
5-7 day course of amoxicillin, if intolerant/allergic use clarithromycin or erythrymoycin.
What OTC treatment is available for otitis externa?
Give minimum age, medication and duration of treatment.
Consider use of over-the-counter acetic acid 2% ear drops or spray (for people aged 12 years and older) morning, evening, and after swimming, showering, or bathing, for a maximum of 7 days
Which antibiotic is associate with red man syndrome? What are the symptoms of red man syndrome and why does it happen?
Vancomycin
symptoms: itchy red rash to the face, neck and upper torso.
Rapid infusion rates increases risk; vancomycin should not be administered more than 10mg/min over no less than 60mins.
Which antibiotics are first-line in throat infections
Phenoxymethylpenicillin for 5-10 days
(alternative clarithromycin or erythromycin in pregnancy)
What is first line for bites from human, cat, dog or other pets?
What is the alternative if patient has allergies.
1st line: Co-amoxiclav
Alternative: Doxycycline with metronidazole
