Infection Flashcards
Name tetracyclines
doxycycline, demeclocycline, lymecycline, minocycline, oxytetracycline, tetracycline, tigecycline
what is on the label of tetracyclines
do not take milk, indigestion remedies, or medicines containing iron or zinc, 2 hours before or after you take this medicine
which tetracyclines are okay with metal ions
- Doxycycline
- Lymecycline
- Minocycline
Does Like Milk
Side effects of tetracyclines
- benign intracranial hypertension - stop & report headache/visual disturbance
- lupus-erythematous like syndrome and irreversible pigmentation in sunlight
- teeth discolouration and bone deposits
which tetracycline has biggest risk of pigmentation in the sun
minocycline
who should you avoid tetracycline in
- under 12 years old
- pregnant
tetracyclines counselling points
- hepatotoxicity - avoid in liver failure
- photosensitivity = avoid sunlight/sunlamps
- dysphagia = swallow whole, plenty fluid, while sitting/standing
- caution in myasthenia gravis
Metronidazole side effects
- taste disturbance (metallic taste/furred tongue)
- NV (take with/after food)
What to avoid with metronidazole
- alcohol during and 48 hours after treatment
- causes disulfiram reactions (NV, flushing)
When to avoid nitrofurantoin
- pregnant = avoid at term
- eGFR < 45
Nitrofurantoin administration directions
with/after food
Nitrofurantoin urine colour
yellow/brown
Trimethoprim cautions
- blood dyscrasias - fever, sore throat, rash, mouth ulcers, bruising, bleeding
- antifolate so interaction with MTX, phenytoin, folic acid
- hyperkalaemia
- caution in renal impairment
Name quinolones
ciprofloxacin, delafloxacin, levofloxacin, moxifloxacin, ofloxacin
Quinolones cause
- reduce seizure threshold (avoid in epilepsy) - also with NSAIDs
- psychiatric and tendon disorders
- allergies
- reduce sunlight and UV exposure
- may impair driving ability
Quinolones MHRA warnings
- tendonitis
- risk of aortic aneurysm and dissection - sever abdo, chest, back pain
- risk of heart valve regurgitation - SOB, peripheral oedema, new heart palpitations
Quinolones cautions
- QT prolongation
- myasthenia gravis
- arthropathy in children/adolescents
- perforated tympanic membrane when used by ear
Quinolones interactions
- dairy/mineral - fortified milk (reduces absorption)
- drugs causing QT prolongation
- drugs reducing seizure threshold (NSAIDs)
Chloramphenicol common indication
eye infection
Chloramphenicol OTC age
2 years and over
Chloramphenicol contraindication
pregnancy - ‘grey baby syndrome’ if used in 3rd trimester
Clindamycin side effects
- abx-associated colitis (fatal) - more common in elderly, discontinue & contact dr ASAP if severe, prolonged, or bloody diarrhoea
- suspected C. diff - stop, specialist advice if cant stop
Linezolid side effects
- severe optic neuropathy - monitor eyes regularly if tx > 28 days
- blood disorders - FBC weekly if tx > 10-14 days
Linezolid interactions
- tyramine - mature cheese, marmite, yeast extract, fermented soya bean extract, some beers and wines
- serotonin syndrome - SSRIs, dopaminergic, 5-HT1 agonists, TCAs, Lithium, MAOIs - altered cognitive state = coma
Name narrow spec penicillins
- Pen G (benzylpenicillin) - parenteral use only (not gastric acid stable)
- pen V (phenoxymethylpenicillin)
Name broad spec penicillins
- ampicillin
- amoxicillin
- co-amoxiclav (b-lactamase resistant)
Broad spec penicillins side effects
- diarrhoea common - abx-associated colitis
- maculopapular rashes common in patients with glandulofever - dont use broad spec blindly for sore throat
Name Penicillinase - resistant penicillins and give details
- flucloxacillin
- take on empty stomach 1 hour before or 2 hours after food (after hard as QDS)
- cholestatic jaundice/hepatitis risk unto 2 months after stopping. Risk = administration > 2 wks, increased age - same for co-amox
Name antipseudomonal penicillins
- piperacillin only available with tazobactam
- ticarcillin only available with clavulanic acid
Penicillins side effects
- DONT give intrathecally - encephalopathy = FATAL
- true pen allergy = immediate rash, anaphylaxis
- may not be allergy = minor rash, small, not itchy, non-confluent, rash after 72 hours
- cross-sensitivity = cephalosporins
Name 1st gen cephalosporins
- Cefadroxil
- Cefalexin
- Cefradine
Fad, Fal, Frad
Name 2nd gen cephalosporins
- Cefuroxime
- Cefoxitin
- Cefaclor
Furry Fox Face
3rd and 5th gen cephalosporins
all parenteral except oral cefixime
Cephalosporins contraindications
penicillins and other b-lactams due to cross sensitivity
Name glycopeptides
dalbavanacin, teicoplanin, telavancin, vancomycin
Vancomycin details
- parenterally for systemic infections (reduced absorption orally)
- avoid in preg unless benefits > risk
- initial dose by body weight then adjust based on levels
Vancomycin levels
- trough = 15-20mg/L
- measure before next dose
Vancomycin interactions
- ototoxicity - cisplatin, vinka alkaloids, aminoglycosides, loop diuretics
- nephrotoxicity - NSAIDs, ACEi, ARBs, Metformin, diuretics
Vancomycin side effects
- red man syndroms
- steven johnson syndrome
- blood dyscrasias
- cardiogenic shock on rapid IV injection
- anaphylactoid reactions at infusion sites - avoid rapid infusion, rotations sites
Name macrolides
- azithromycin - OD (COPD prophylaxis = 3x week)
- clarithromycin - BD
- erythromycin - QDS
Macrolides cautions
- myasthenia gravis
- erythro > clarithro in pregnancy
- avoid clarithro in 1st trimester
Macrolides side effects
- hepatotoxicity
- ototoxicity in large doses
- increased GI disturbances
- QT prolongation
Macrolides interactions
- macrolides = CYP inhibitors so increase levels of statins and warfarin (myopathy/bleeding)
- hypokalaemia - diuretics, steroids, salbutamol, theophylline
- increased QT prolongation - amiodarone, domperidone, fluconazole, lithium, SSRIs, methadone, ondansetron, quinine, quinolones, sotalol
Name aminoglycosides
- amikacin, gentamicin, neomycin, streptomycin, tobramycin
Who should serum concentrations of aminoglycosides be taken for
- all patients receiving parenteral aminoglycosides
- must be determined in obesity, high doses, cystic fibrosis, elderly
Gentamicin levels
- after 3 or 4 doses, then every 3 days or after a dose change, more frequent if renal impairment
- measure 1 hour after dose and just before next dose
Gentamicin multiple daily dose regimen level targets
- peak = 5-10mg/L
- peak in endocarditis = 3-5mg/L bcos co-prescribed with other abx
- trough = <2 mg/L
- trough in endocarditis = < 1 mg/L as co-prescribed with other abx
Gentamicin dose adjustments based on levels
- trough too high = increase dose interval
- peak too high = decrease dose
- renal impairment = increase interval, decrease dose if severe - avoid concomitant use of nephrotoxics
Gentamicin interactions
- ototoxicity - cisplatin, loop diuretics, vancomycin, vinka alkaloids
- nephrotoxicity - NSAIDs, ACEi, ARBs, Metformin, diuretics
Gentamicin contraindications
- myasthenia gravis
- pregnancy - risk of auditory or vestibular nerve damage - monitor serum concs
Gentamicin dose in obesity
use ideal body weight based on height to calculate parenteral dose
Aims of antimicrobial stewardship
- prevents resistance
- less unnecessary treatment, more caution
- higher risk of resistance with broad spec abx
Antimicrobial stewardship NICE guidance
- only start abx if clinical evidence of bacteria
- follow local guidelines
- futures to narrow spectrum
- avoid broad spec if possible
- avoid widespread use of topical abx especially if systemic available
Which abx come with risk of C. diff, MRSA, abx resistant UTIs
- co-amox
- quinolones (ciprofloxacin)
- cephalosporins
- clindamycin
Most common pathogen of CAP
streptococcus pneumoniae
Most common pathogen of UTIs
escherichia coli
Most common pathogen of thrush
candida albicans
Most common pathogen of cellulitis
staphylococcus aureus
Most common pathogen of meningitis
streptococcus pneumoniae
Most common pathogen of sore throat
streptococci
Treatment of human/animal bites
- co-amox
- doxy + metro
- prophylaxis = 3 days, Tx = 5 days
- scratches = fluclox
Treatment of tick bites (Lyme disease)
- doxy (100mg BD)
- amoxicillin (1g TDS)
- Tx = 21 days
Cellulitis treatment
- fluclox
- alt: clarithro (erythro-preg), or doxy, or co-amox - near eyes/nose = co-amox
- alt: clarithro and metro
mild CAP treatment
- amox
- doxy or clarithro (erythro-preg)