CBM - Prescribing Antibiotics for self limiting RTIs Flashcards
Px Antibiotics for
Self Limiting URTIs
PENNICLIN β-lactams Benzylpennicilin (penicillin G) phenoxymethylpennicilin (penicillin V)
Indications?
- acute pharyngitis,
- tonsillitis,
- sore throat,
- otitis media,
- oral infection,
- cellulitis,
- streptococcal (including pneumococcal ),
- erysipelas,
- clostridail infection,
- meningococcal,
- gonococcal,
- lyme disease,
- gangrene
Px Antibiotics for
Self Limiting URTIs
PENNICLIN β-lactams Benzylpennicilin (penicillin G) phenoxymethylpennicilin (penicillin V)
Dose/Side Fx/Warnings/Interaction
DOSE
- Benzylpenicillin (penicillin G) IV OR IM 1.2g every 4-6hrly
- Phenoxymethylpenicillin (penicillin V) orally .Adult 500mg 6hrly increase dose if necessary
SIDE EFFECT
- Allergy and cross-sensitivity
- CNS toxicity
- Patient with hx of hypersensitivity with penicillin
WARNING
- Dose reduction for pt with renal impairment
- Hx of allergy
- Accumulation of Na from injection Benzylpennicilin (penicillin G) can occur renal failure
- High dose may cause neurotoxicity
INTERACTION
- Penicillin reduce renal excretion of methotrexate increasing risk toxicity
Px Antibiotics for
Self Limiting URTIs
PENNICILIN (BROAD-SPECTRUM) AMOXICILIN, CO-AMOXICLAV
INDICATION
- sinusitis,
- otitis media,
- oral infection,
- respiratory track,
- acute bronchitis,
- UTI,
- CAP,
- salmonellosis,
- cellulitis,
- genito-urinary
- abdominal infection,sepsis
Px Antibiotics for
Self Limiting URTIs
PENNICILIN (BROAD-SPECTRUM) AMOXICILIN, CO-AMOXICLAV
Contr-indications/Side Fx/Interactions/Dose
CONTRA-INDICATION-
- hx of CO-AMOXICLAV associate hepatic jaundice or hepatic dysfunction
SIDE EFFECTS
- GI upset-diarrhoea, nausea
- Abx associated colitis
- Penicillin allergy
- Cholestatic jaundice -rare
WARNING
- Reduce dose in pt with renal impairment risk of crystalluria
- Hx of penicillin allergy
- Monitor liver function in pt with liver impairment
INTERACTION
- Reduce renal excretion of methotrexate, increase toxicity
- Can enhance anticoagulant effect of warfarin
DOSE
- AMOXICILLIN orally –adult 500mg 8hrly
- CO-AMOCILAV-250/125 mg 8hrly, increase dose 500/125mg in severe infection
Px Antibiotics for
Self Limiting URTIs
MACROLIDES-Erythromycin, azithromycin, clarithromycin (alternative to penicillin)
Indications
- respiratory tract infection (mycoplasma pneumonia)
- skin,
- soft tissue and oral infection,
- otitis media,
- Legionella infection,
- campylobacter enteritis,
- chlamydia)
Px Antibiotics for
Self Limiting URTIs
MACROLIDES-Erythromycin, azithromycin, clarithromycin (alternative to penicillin)
MOA/Dose/Side Fx/Warnings/Interactions
Mechanism of action:
- inhibits bacterial protein synthesis (BATERIOSTATIC ACTIVITY)
DOSE:
- Clarithromycin mostly prescribed in the UK 250mg-500mg 2xdaily 7-14day
- Erythromycin 250-500mg 4x daily or 500-100mg for 5day
SIDE EFFECT:
- QT prolongation
- Irritant- abdominal pain, nausea and vomiting, diarrhoea
- Ototoxicity at high dose
- Allergic antibiotic associated colitis
WARNING:
- Metabolized by the liver, small amount in the kidney
- Avoid in severe hepatic /renal impairment
- Avoid in pregnancy/ breastfeeding except if benefit outweigh risk
- caution in drugs that prolong OT interval eg amiodarone, antipsychotic drugs and SSRI, quinine
INTERACTION:
- warfarin risk of bleeding. Statin- risk of myopathy
- Also interact with digoxin, theophylline, carbamazepine
