Infections- HIGH Flashcards
What factors need to be considered when selecting antibacterials?
- Allergies
- Renal and hepatic function
- Immunocompromised?
- Severity of illness (e.g. life-threatening require IV admin.)
- Other medication
- Pregnant/breast-feeding
When may IV admin. be suitable in a non-life-threatening infection?
- Nil-by-mouth patients e.g. swallow difficulties
- Vomiting
What is phenoxymethylpenicillin used as prophylaxis for?
- Prevent recurrence of rheumatic fever
- Prevent streptococcal infection, pneumococcal infection in asplenia
What is isoniazide +/- rifampicin used as prophylaxis for?
Prevent TB in susceptible patients
What is IV gentamicin used as prophylaxis for?
Prevent infection in surgical procedures
What infection is associated with broad-spectrum cephalosporins?
Antibiotic associated colitis (C. diff)
When are anaphylaxis, urticaria and rash more common in patients?
Those with a history of atopic allergy e.g. bronchial asthma
Common side effects of penicillins?
- Diarrhoea
- Hypersensitivity
Which other antibiotics may allergic patients also react to due to similarity?
- Cephalosporins e.g. cephalexin
- Beta lactam antibiotics
Is a rash always an allergic reaction?
No- a non-pruritic rash restricted to a small area or occurring > 72 hours after admin. is probably not allergic
What is benzylpenicillin (penicillin G) indicated for?
Points to consider?
Indicated for throat infections, otitis media, cellulitis, meningococcal disease, septicaemia
- MUST be given IV/IM- inactivated by gastric acid (and bacterial beta-lactamases)
- May impair efficacy of oral contraceptives
What is Phenoxymethylpenicillin (Penicillin V) indicated for?
Points to consider?
Indicated for RTIs in children, strep tonsillitis
- Should be given (orally) in divided doses (TDS/QDS) half an hour before meals
- Total daily dose usually 1-2g in divided doses
What is flucloxacillin indicated for?
Points to consider?
MAX daily dose?
Indicated for otitis externa, cellulitis, osteomyelitis
- Acid stable and well absorbed from gut (can be oral or IV)
- Should NOT be used in hepatic dysfunction (can cause liver injury- DILI)
- Take 30 mins before food
- MAX: 500mg every 6 hrs
What kind of infections is temocillin reserved for?
Infections caused by beta-lactamase-producing strains of Gram-negative bacteria
What is ampicillin (broad spec) indicated for?
Points to consider?
MAX daily dose?
Indicated for chronic bronchitis, middle ear infections and UTIs
- Inactivated by penicillinases
- Less than half dose absorbed orally (take 30 mins before food)
- Consider resistance- do not use for hospital patients without checking sensitivity
- MAX 1g every 6 hours
What is amoxicillin (broad spec) indicated for?
Indicated for oral infections, sinusitis, pharyngitis, bronchitis, pyelonephritis
- Better absorption than ampicillin
- MAX daily dose 1g every 8 hours
What is co-amoxiclav indicated for?
Points to consider?
MAX daily dose?
Used to treat RTIs, UTIs and abdominal infection
- Amoxicillin + Clavulanic acid
- Active against beta-lactamase producing bacteria resistant to amoxicillin
- Cholestatic jaundice 6x greater with co-amoxiclav than amoxicillin
- MAX: one 500mg/125mg tab every 8 hrs
What is piperacillin + tazobactam indicated for?
What is its brand name?
Indicated for hospital acquired pneumonia (HAP), septicaemia, complicated UTIs
- Brand: Tazocin
- Given by IV infusion
What is clavulanic acid’s function?
It is a beta-lactamase inhibitor- protecting beta-lactam antibiotics from breakdown
What is Ticarcillin + clavulanic acid indicated for?
What is its brand name
Points to consider?
Indicated for infections due to pseudomonas and proteus species
- Cholestatic jaundice associated with clavulanic acid
- Given by IV infusion
Which generations of cephalosporins are good for unresponsive UTI or UTI in pregnancy?
First and second
What is cefaclor (Distaclor, Distaclor LA) indicated for?
Typical dosing schedules?
Indicated for pneumonia, lower UTI
- 250mg every 8 hrs (doubled in severe)
- Distaclor LA (375mg BD with food, double in pneumonia)
- Distaclor LA forte (500mg BD)
What is cefalexin indicated for?
Typical dosing schedules?
Indicated for UTI prophylaxis, HAP
- 250mg every 6 hrs, or 500mg every 12 hrs
- 125mg nocte for UTI prophylaxis
What is cefuroxime indicated for?
Typical dosing schedule?
Indicated for haemophilus influenzae, RTI, pyelonephritis
500mg BD
What is ertapenem indicated for?
Community-acquired pneumonia (CAP)
What is meropenem indicated for?
Hospital-acquired septicaemia
What is imipenem indicated for?
Hospital-acquired septicaemia
Points to consider re macrolides?
SE etc?
- Similar spectrum to penicillin- alternative in penicillin allergy
- Caution in patients predisposed to QT interval prolongation
- S/E: GI upset
What is azithromycin indicated for?
Dosing schedule?
Indicated for RTI, otitis media, gonorrhoea and chlamydia
- 500mg OD for 3/7
- 1g single dose for gonorrhoea and chlamydia
What is clarithromycin (Klacid) indicated for?
Dosing schedule?
Points to consider?
Indicated for RTI, otitis media and H. Pylori (with PPI)
- CYP3A4 inhibitor
- 250-500mg BD for 7-14 days
- Klacid MR: one 500mg tab daily
What is erythromycin indicated for?
Dosing schedule?
Points to consider?
Indicated for RTI, pneumococcal infection, chlamydia and syphilis
- CYP3A4 inhibitor
- 1-2g daily in divided doses
- 250-500mg every 6 hrs (Alternatively 0.5-1g every 12 hrs)
Preferred macrolide with patient on warfarin?
Erythromycin preferred- greater risk of increased INR (bleeding risk)
Points to consider for tetracyclines?
- Broad spectrum
- May increase muscle weakness in patients with myasthenia gravis
- Antacids, milk, Ca, Mg, Fe, Zn, Al salts decrease absorption (take 1-2 hours before)
When are tetracyclines contraindicated?
- Pregnancy/BF- effects skeletal development and causes tooth discolouration
- < 12 y/o- deposits in teeth and bone causing staining & dental hypoplasia
S/E of tetracyclines?
- GI upsets, dysphagia, oesophageal irritation
- Hepatotoxicity
- Photosensitivity
To reduce oesophageal irritation, take whole with plenty of fluid, while sitting or standing
What is tetracycline indicated for?
Dosing schedule?
S/E?
Indicated for acne
- 500mg every 6-8 hrs
- S/E: skin discolouration
What is doxycycline indicated for?
Dosing schedule? MAX daily dose?
Indicated for sinusitis, malaria prophylaxis
- Longer duration of action than tetracycline or oxytetracycline- allows OD dosing
- 100mg day one, then 100mg daily
- MAX: 200mg daily
What is lymecycline indicated for?
Dosing schedule?
Indicated for acne
- 408mg daily for at least 8 weeks
What is minocycline (Minocin SA(MR)) indicated for?
Points to consider?
Dosing schedule?
indicated for acne (min. 6 weeks and max. 6 months)
- 100mg BD
- Minocin MR- 100mg OD for acne
- If no response after 6 months, discontinue and try other therapies
- Unlike other tetracyclines, absorption not impaired by food or milk
What is oxytetracycline indicated for?
Indicated for acne, rosacea
- MAX dose 500mg every 6 hrs
What are the S/E of aminoglycosides?
Where are they more common?
Nephrotoxicity and ototoxicity
- Dose related
- Elderly more susceptible to ototoxicity
- Most common in elderly & renal failure
How can aminoglycoside S/E be managed?
- Dose reduction may be required in elderly
- Monitor serum-concentration
- Do not give with ototoxic drugs i.e. cisplatin, furosemide
Monitoring requirements for aminoglycosides?
- Renal function before and during treatment
- Auditory and vestibular function tests during treatment
What is gentamicin indicated for?
Usually combined with…?
Points to consider?
Indicated for septicaemia, neonatal sepsis, CNS infection and HAP
- Usually given with a penicillin or metronidazole
- Loading & maintenance doses calculated by weight/renal function/serum concentrations
What is neomycin sulfate indicated for?
Used in bowel sterilisation prior to surgery
What is streptomycin indicated for?
What should peak and trough serum conc. be while monitoring?
Active against Mycobacterium tuberculosis- entirely reserved for TB
- One-hour (‘peak’) concentration should be 15-40mg/L
- Pre-dose (‘trough’) concentration should be < 5mg/L (less than 1mg/L in renal impairment or those > 50 y/o)
What is tobramycin indicated for?
Monitoring?
Points to consider?
Indicated for septicaemia, meningitis, HAP, UTI, Chronic Pseudomonas aeruginosa in cystic fibrosis
- Taken by IV or inhalation
- Measure lung function before and after treatment
- Monitor bronchospasm
What is chloramphenicol indicated for?
indicated for superficial eye infections, bacterial infection in otitis externa (topical)
Life-threatening infections, particularly those caused by Haemophilus influenzae (systemic use)
Typhoid (systemic use)
S/E for chloramphenicol?
- Serious haematological S/E i.e. aplastic anaemia when given systematically
- Chronic exposure has lead to bone marrow hyperplasia
Dosing for chloramphenicol drops and ointment?
- Drops: 1-2 drops applied to affected eyes up to 6 times daily
- Ointment: Apply 1cm ribbon 3-4 times daily
What is sodium fusidate (Fucidin) indicated for?
Penicillin-resistant staphylococci i.e. osteomyelitis, as it concentrates in bone