Amoxicillin
Indications
Amoxicillin is used for:
Bacterial infections,Pharyngitis,Acute otitis media,Acute bacterial sinusitis,Endocarditis,Anthrax,Chlamydial cervicitis,Chlamydial urethritis,Lyme disease,Dental abscess,Salmonellosis,Typhoid fever,Acute Uncomplicated gonorrhea,Infections of the Lower Respiratory Tract,Skin and Skin Structure,Genitourinary Tract,Ear,Nose,Throat
Adult Dose
Adult: PO Susceptible infections 250-500 mg 8 hrly. Uncomplicated gonorrhoea W/ probenecid: 3 g as a single dose. Dental abscesses 3 g, repeat once 8 hr later.
Uncomplicated acute UTI 3 g, repeat once 10-12 hr later. Prophylaxis of endocarditis 2 or 3 g as a single dose, 1 hr before dental procedure.
Severe or recurrent resp tract infections 3 g twice daily.
H.pylori infection W/ either metronidazole or clarithromycin and a bismuth compound or an antisecretory drug: 500 mg 3 times/day.
IV/IM Susceptible infections 500 mg 8 hrly. Listerial meningitis W/ other antibiotics: 2 g 4 hrly for 10-14 days.
Child Dose
Child: PO Standard dose: 40–45 mg/kg/day q8-12h
High dose: 80–90 mg/kg/day, max 4 g/day q12h
150 mg/kg/day div q8h for penicillin-resistant S pneumoniae otitis media
Renal Dose
Renal impairment: Patients on haemodialysis should receive 250-500 mg every 24 hr and an additional dose during and after each dialysis session.
CrCl (ml/min)
10-30 250-500 mg every 12 hr.
<10 250-500 mg every 24 hr.
Administration
May be taken with or without food. May be taken w/ meals for better absorption & to reduce GI discomfort.
Contra Indications
Hypersensitivity
Precautions
Renal and hepatic disease; pregnancy, lactation; infectious mononucleosis.
Lactation: Excreted in breast milk, use caution
Pregnancy-Lactation
Interactions
May reduce the efficacy of OC. May increase the effect of anticoagulants. Increased risk of allergic reactions w/ allopurinol. Increased and prolonged blood levels w/ probenecid. Chloramphenicol, macrolides, sulfonamides and tetracyclines may interfere w/ the bactericidal effect of amoxicillin.
Adverse Effects
Side effects of Amoxicillin :
Hyperactivity, agitation, insomnia, dizziness; maculopapular rash, exfoliative dermatitis, urticaria, hypersensitivity vasculitis; diarrhoea, nausea, vomiting; anaemia, thrombocytopenia, leucopenia, agranulocytosis.
Potentially Fatal: Neuromuscular hypersensitivity; pseudomembranous colitis.
Mechanism of Action
Amoxicillin inhibits the final transpeptidation step of peptidoglycan synthesis in bacterial cell wall by binding to one or more of the penicillin-binding proteins (PBPs), thus inhibiting cell wall biosynthesis resulting in bacterial lysis.