amoxicillin (Amoxil, Polymox, Larotid, Trimox, DisperMox, Moxatag, A-cillin)
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Introduction
Tradenames: Amoxil, Polymox, Larotid, Trimox. 3rd generation penicillin. (amoxicillin trihydrate)
Indications
- treatment of:
- urinary tract infections (UTI)
- upper & lower respiratory tract infections
- skin infections (cellulitis) & soft tissue infections
- treatment of gastritis due to Helicobacter pylori infection in combination with clarithromycin & lansoprazole
- acute otitis media[10]
- pharyngitis
- prophylaxis for bacterial endocarditis
- 2 g 1 hour prior to procedure
- antibiotic activity (including Enterococcus) similar to ampicillin
- empiric treatment of fever of unknown origin[10]
- susceptible bacterial infections
Contraindications
Caution: avoid in patients with hypersensitivity to penicillin
Dosage
Pediatrics: 40 mg/kg/day divided TID.
Tabs: 125, 250, 500 mg.
Elixir: 125 & 250 mg/5 mL. (80 & 150 mL)
Dispersible tablets (DisperMox):
Moxatag QD dosing
Dosage adjustment in renal failure
Table
| 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
- rapid & nearly complete absorption after oral administration
- widely distributed to most tissues, body fluids & bone
- pentration into cells, eyes & across normal meninges is poor
- inflammation of meninges increases CSF penetration
- protein-binding 17-20%
- elimination 1/2life is 1 hour; longer in infants & children (5-20 hours ESRD)
elimination via kidney
1/2life = 1 hours
elimination by hemodialysis = +
protein binding = 17-20 %
Adverse effects
(not common, 1-10%)
- rash (especially in patients with mononucleosis)
- hypersensitivity reactions (may manifest as urticarial rash that appears after a few days of therapy)*
- drug-induced serum sickness-like reaction
- typically after 1-2 weeks
- serpiginous maculopapular eruptions, urticaria
- fever
- arthralgias[12]
- acute interstitial nephritis
- diarrhea
- blood dyscrasias (rare)
- seizures (rare)
- drug fever
- vaginitis
- lower incidence of adverse effects (especially diarrhea) compared with ampicillin
- 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
- coadministration of allopurinol increases the frequency of rash
- probenecid prolongs 1/2 life of amoxicillin by 30-60%
- drug interaction(s) anticonvulsants with anti-bacterial agents
- drug interaction(s) of antibiotics with warfarin
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
More general terms
Component of
- amoxicillin/clarithromycin/vonoprazan
- amoxicillin/omeprazole/rifabutin
- amoxicillin/clarithromycin/omeprazole
- amoxicillin/clarithromycin/lansoprazole (PrevPak, ACL)
- amoxicillin/clavulanate (Augmentin)
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ Sanford Guide to antimicrobial therapy 2001
- ↑ 5.0 5.1 Geriatric Dosage Handbook, 6th edition, Selma et al eds, Lexi-Comp, Cleveland, 2001
- ↑ 6.0 6.1 Prescriber's Letter 10(11):64 2003
- ↑ 7.0 7.1 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: https://www.ncbi.nlm.nih.gov/pubmed/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: https://www.ncbi.nlm.nih.gov/pubmed/16203949
Prescriber's Letter 12(9): 2005 Amoxicillin and tooth enamel defects Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=211110&pb=PRL (subscription needed) http://www.prescribersletter.com - ↑ Prescriber's Letter 15(4): 2008 Comparison of Amoxicillin Products Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=240408&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ Prescriber's Letter 16(2): 2009 New Formulation: Moxatag (Amoxicillin Extended-release) Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=250206&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 10.0 10.1 10.2 10.3 10.4 Deprecated Reference
- ↑ 11.0 11.1 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: https://www.ncbi.nlm.nih.gov/pubmed/27043788
- ↑ 12.0 12.1 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: https://www.ncbi.nlm.nih.gov/pubmed/17709052