Amoxicillin (aka amoxycillin)
[one tablet 6 cents; 1 vial for IV injection $2.17]
- IV, PO, NG
- Apo-Amoxi , Ospamox, Ranbaxy-Amoxi, Ibiamox
- treatment of infections caused by susceptible organisms
- empirical treatment to cover enterococcus
PRESENTATION AND ADMINISTRATION:
1g vial (powder). Dilute to total of 5ml if part dose is required (making concentration of 200mg/ml). Inject slowly over 3-4 minutes or in 100ml of compatible fluid over 30-60 minutes.
Compatible for 6 hours with normal saline, 3 hours with Hartmanns, 1 hour with D5W and glucose and sodium. (note that amoxicillin is less stable in solutions that contain glucose so it is preferable to avoid these solutions).
Store at room temperature
- PO / NG:
Apo-Amoxi 250mg tablets & 500mg tablets (red/gold, marked APO and strength), Ospamox capsules 500mg capules (yellow), Ospamox suspension (125mg/5ml and 250mg/ml), Ranbaxy-Amoxi (125mg/5ml and 250mg/5ml), Amoxil paediatric drops (125mg/1.25ml), Ospamox paediatric drops (100mg/ml). administration.
1-2gm IV Q6hrly
Liquid is preferred for NG
DOSAGE IN RENAL FAILURE AND RENAL REPLACEMENT THERAPY:
- Dose in renal impairment [GFR (ml/min)]
<10: 500mg every 8 hours
10-20: dose as in normal renal function
>20-50: dose as in normal renal function
- Dose in renal replacement therapy
CAPD: 500mg every 8 hours
HD: 500mg every 8 hours
CVVHDF: dose as in normal renal function
DOSAGE IN PAEDIATRICS:
1st week of life 50mg/kg 12hrly; otherwise 50mg/kg 6hrly
- Amoxicillin is bactericidal against susceptible organisms during the stage of active multiplication. It acts through the inhibition of biosynthesis of cell wall mucopeptide.
- Amoxicillin has been shown to be active against most strains of the following microorganisms:
Aerobic Gram-Positive Microorganisms:
Enterococcus faecalis. Staphylococcus spp*. (beta-lactamase-negative strains only). Streptococcus pneumoniae.
*Staphylococci which are susceptible to amoxicillin but resistant to methicillin/oxacillin should be considered as resistant to amoxicillin.
Aerobic Gram-Negative Microorganisms:
Escherichia coli (beta-lactamase-negative strains only). Haemophilus influenzae (beta-lactamase-negative strains only). Neisseria gonorrhoeae (beta-lactamase-negative strains only). Proteus mirabilis (beta-lactamase-negative strains only).
- Amoxicillin diffuses readily into most body tissues and fluids, with the exception of brain and spinal fluid, except when meninges are inflamed.
- A history of allergic reaction to any of the penicillins is a contraindication.
Penicillins are a common cause of anaphylactic reactions
- Pseudomembranous colitis:
Pseudomembranous colitis has been reported with nearly all antibacterial agents, including amoxicillin, and may range in severity from mild to life-threatening. Therefore, it is important to consider this diagnosis in patients who present with diarrhoea subsequent to the administration of antibacterial agents.
Prescribing Amoxicillin in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug resistant bacteria.
- Laboratory Tests:
No tests in addition to routine ICU tests are required.
- Drug/Laboratory Test Interactions:
IMPORTANT DRUG INTERACTIONS FOR THE ICU
- None of significance
- Body as a Whole:
Serum sickness like reactions, Anaphylaxis
- Digestive System:
Nausea, vomiting, diarrhea, and hemorrhagic/pseudomembranous colitis. Hepatic dysfunction including cholestatic jaundice, hepatic cholestasis and acute cytolytic hepatitis have been reported.
- Nervous System:
Reversible hyperactivity, agitation, anxiety, insomnia, confusion, convulsions, behavioral changes, and/or dizziness have been reported rarely.
Stevens-Johnson Syndrome, exfoliative dermatitus, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, hypersensitivity vasculitis and urticaria have been reported
- Haematological System:
Anaemia, including hemolytic anaemia, thrombocytopaenia, thrombocytopenic purpura, eosinophilia, leukopaenia, and agranulocytosis have been reported during therapy with penicillins.