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amoxicillin (Amoxil, Polymox, Larotid, Trimox, DisperMox, Moxatag, A-cillin)

Tradenames: Amoxil, Polymox, Larotid, Trimox. 3rd generation penicillin. (amoxicillin trihydrate) Indications: 1) treatment of: a) urinary tract infections (UTI) b) upper & lower respiratory tract infections - acute sinusitis [10] c) skin infections (cellulitis) & soft tissue infections d) treatment of gastritis due to Helicobacter pylori infection in combination with clarithromycin & lansoprazole e) acute otitis media [10] f) pharyngitis 2) prophylaxis for bacterial endocarditis - 2 g 1 hour prior to procedure 3) antibiotic activity (including Enterococcus) similar to ampicillin 4) empiric treatment of fever of unknown origin [10] 5) susceptible bacterial infections - Streptococcus - Streptococcus pyogenes - Streptococcus pneumoniae - Staphylococcus - Haemophilus influenzae - Escherichia coli - Proteus [10] Contraindications: Caution: avoid in patients with hypersensitivity to penicillin Dosage: 250-500 mg PO TID. Pediatrics: 40 mg/kg/day divided TID. Tabs: 125, 250, 500 mg. Elixir: 125 & 250 mg/5 mL. (80 & 150 mL) Dispersible tablets (DisperMox): -> disperse in water immediately before dosing [6] Moxatag QD dosing Dosage adjustment in renal failure: creatinine clearance dose 10-50 mL/min 250-500 mg every 12 hours < 10 mL/min* 250-500 mg every 24 hours * dose after hemodialysis [5] Pharmacokinetics: 1) rapid & nearly complete absorption after oral administration 2) widely distributed to most tissues, body fluids & bone a) pentration into cells, eyes & across normal meninges is poor b) inflammation of meninges increases CSF penetration c) protein-binding 17-20% d) elimination 1/2life is 1 hour; longer in infants & children (5-20 hours ESRD) Adverse effects: (not common, 1-10%) 1) rash (especially in patients with mononucleosis) 2) hypersensitivity reactions (may manifest as urticarial rash that appears after a few days of therapy)* 3) drug-induced serum sickness-like reaction - typically after 1-2 weeks - serpiginous maculopapular eruptions, urticaria - fever - arthralgias [12] 4) acute interstitial nephritis 5) diarrhea 6) blood dyscrasias (rare) 7) seizures (rare) 8) drug fever 9) vaginitis 10) lower incidence of adverse effects (especially diarrhea) compared with ampicillin 11) fluorosis when used during infancy, especially 1st 6 months of life [7] * oral provocation challenge to amoxicillin safe & more accurate than skin testing [11] Drug interactions: 1) coadministration of allopurinol increases the frequency of rash 2) probenecid prolongs 1/2 life of amoxicillin by 30-60% Laboratory: - amoxicillin in serum/plasma - amoxicillin in CSF - amoxicillin IgE - amoxicillin-induced neutrophil IgG - amoxicillin-induced neutrophil IgM - amoxicillin-induced platelet IgG - amoxicillin-induced platelet IgM Mechanism of action: - inhibition of bacterial wall synthesis

Interactions

drug interactions

General

3rd generation penicillin (aminopenicillin)

Properties

MISC-INFO: elimination route KIDNEY 1/2life 1 HOURS elimination by hemodialysis + protein-binding 17-20% pregnancy-category B safety in lactation ?

Database Correlations

PUBCHEM correlations

References

  1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
  2. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
  3. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  4. Sanford Guide to antimicrobial therapy 2001
  5. Geriatric Dosage Handbook, 6th edition, Selma et al eds, Lexi-Comp, Cleveland, 2001
  6. Prescriber's Letter 10(11):64 2003
  7. Hong L, Levy SM, Warren JJ, Dawson DV, Bergus GR, Wefel JS. Association of amoxicillin use during early childhood with developmental tooth enamel defects. Arch Pediatr Adolesc Med. 2005 Oct;159(10):943-8. PMID: 16203939 - Casamassimo PS. Amoxicillin and fluorosis: too soon to cap the medicine bottle? Arch Pediatr Adolesc Med. 2005 Oct;159(10):995-6. No abstract available. PMID: 16203949 - Prescriber's Letter 12(9): 2005 Amoxicillin and tooth enamel defects Detail-Document#: 211110 (subscription needed) http://www.prescribersletter.com
  8. Prescriber's Letter 15(4): 2008 Comparison of Amoxicillin Products Detail-Document#: 240408 (subscription needed) http://www.prescribersletter.com
  9. Prescriber's Letter 16(2): 2009 New Formulation: Moxatag (Amoxicillin Extended-release) Detail-Document#: 250206 (subscription needed) http://www.prescribersletter.com
  10. Deprecated Reference
  11. Mill C et al. Assessing the diagnostic properties of a graded oral provocation challenge for the diagnosis of immediate and nonimmediate reactions to amoxicillin in children. JAMA Pediatr 2016 Apr 4 PMID: 27043788
  12. NEJM Knowledge+ Question of the Week. Jan 31, 2017 http://knowledgeplus.nejm.org/question-of-week/1250/ - Lin B, Strehlow M. Images in emergency medicine. Serum sickness-like reaction to amoxicillin. Ann Emerg Med. 2007 Sep;50(3):350, 359. PMID: 17709052

Component-of

amoxicillin/clarithromycin/lansoprazole (PrevPak, ACL) amoxicillin/clarithromycin/omeprazole amoxicillin/clarithromycin/vonoprazan amoxicillin/clavulanate (Augmentin) amoxicillin/vonoprazan