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Somewhere between 3% and 10% of children taking amoxicillin (or [[ampicillin]]) show a late-developing (>72 hours after beginning medication and having never taken penicillin-like medication previously), often itchy rash, which is sometimes referred to as the "amoxicillin rash." The rash can also occur in adults.<ref>{{cite web|url=http://forums.wrongdiagnosis.com/showthread.php?t=15875 |title=Pretty severe itchy rash after Amoxicillin reaction - WrongDiagnosis.com |publisher=Forums.wrongdiagnosis.com |date= |accessdate=2010-11-13}}</ref><ref>{{cite web|url=http://www.medhelp.org/posts/Allergy/Rash-from-Amoxicillin/show/4008 |title=Rash from Amoxicillin - Allergy |publisher=MedHelp |date= |accessdate=2010-11-13}}</ref>
Somewhere between 3% and 10% of children taking amoxicillin (or [[ampicillin]]) show a late-developing (>72 hours after beginning medication and having never taken penicillin-like medication previously), often itchy rash, which is sometimes referred to as the "amoxicillin rash." The rash can also occur in adults.<ref>{{cite web|url=http://forums.wrongdiagnosis.com/showthread.php?t=15875 |title=Pretty severe itchy rash after Amoxicillin reaction - WrongDiagnosis.com |publisher=Forums.wrongdiagnosis.com |date= |accessdate=2010-11-13}}</ref><ref>{{cite web|url=http://www.medhelp.org/posts/Allergy/Rash-from-Amoxicillin/show/4008 |title=Rash from Amoxicillin - Allergy |publisher=MedHelp |date= |accessdate=2010-11-13}}</ref>


The rash is described as [[maculopapular]] or morbilliform ([[Measles|measles-like]]; therefore, in medical literature, it is called "amoxicillin-induced morbilliform rash"<ref>{{cite web|url=http://cat.inist.fr/?aModele=afficheN&cpsidt=2654598 |title=Role of delayed cellular hypersensitivity and adhesion molecules in amoxicillin-induced morbilliform rashes |publisher=Cat.inist.fr |date= |accessdate=2010-11-13}}</ref>). It starts on the trunk and can spread from there. This rash is unlikely to be a true allergic reaction, and is not a contraindication for future amoxicillin usage, nor should the current regimen necessarily be stopped. However, this common amoxicillin rash and a dangerous allergic reaction cannot easily be distinguished by inexperienced persons, and therefore a healthcare professional should be consulted if a rash develops. (Pichichero, 2005; Schmitt 2005)
The rash is described as [[maculopapular]] or morbilliform ([[Measles|measles-like]]; therefore, in medical literature, it is called "amoxicillin-induced morbilliform rash"<ref>{{cite web|url=http://cat.inist.fr/?aModele=afficheN&cpsidt=2654598 |title=Role of delayed cellular hypersensitivity and adhesion molecules in amoxicillin-induced morbilliform rashes |publisher=Cat.inist.fr |date= |accessdate=2010-11-13}}</ref>). It starts on the trunk and can spread from there. This rash is unlikely to be a true allergic reaction, and is not a contraindication for future amoxicillin usage, nor should the current regimen necessarily be stopped. However, this common amoxicillin rash and a dangerous allergic reaction cannot easily be distinguished by inexperienced persons, and therefore a healthcare professional is often required to distinguish between the two.<ref>(Pichichero, 2005; Schmitt 2005)</ref>


A nonallergic amoxicillin rash may also be an indicator of [[infectious mononucleosis]]: Some studies indicate approximately 80-90% of patients with acute [[Epstein Barr virus]] infection treated with amoxicillin or [[ampicillin]] develop such a rash.<ref>{{cite journal | last=Kagan | first=B | title=Ampicillin rash |journal=Western Journal of Medicine |volume=126 |issue=4 |pages=333–335 |year=1977 |url = http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1237570 | pmid=855325 | pmc=1237570}}</ref>
A nonallergic amoxicillin rash may also be an indicator of [[infectious mononucleosis]]: Some studies indicate approximately 80-90% of patients with acute [[Epstein Barr virus]] infection treated with amoxicillin or [[ampicillin]] develop such a rash.<ref>{{cite journal | last=Kagan | first=B | title=Ampicillin rash |journal=Western Journal of Medicine |volume=126 |issue=4 |pages=333–335 |year=1977 |url = http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1237570 | pmid=855325 | pmc=1237570}}</ref>

Revision as of 02:40, 5 March 2011

Amoxicillin
Clinical data
Pregnancy
category
  • AU: A
Routes of
administration		Oral, intravenous
ATC code
Legal status
Legal status
  • UK: POM (Prescription only)
Pharmacokinetic data
Bioavailability95% oral
Metabolismless than 30% biotransformed in liver
Elimination half-life61.3 minutes
Excretionrenal
Identifiers
  • (2S,5R,6R)- 6-{[(2R)-2-amino- 2-(4-hydroxyphenyl)- acetyl]amino}- 3,3-dimethyl- 7-oxo- 4-thia- 1-azabicyclo[3.2.0]heptane- 2-carboxylic acid
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
KEGG
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.043.625 Edit this at Wikidata
Chemical and physical data
FormulaC16H19N3O5S
Molar mass365.4 g/mol g·mol−1
3D model (JSmol)
  • O=C(O)[C@@H]2N3C(=O)[C@@H](NC(=O)[C@@H](c1ccc(O)cc1)N)[C@H]3SC2(C)C
  • InChI=1S/C16H19N3O5S/c1-16(2)11(15(23)24)19-13(22)10(14(19)25-16)18-12(21)9(17)7-3-5-8(20)6-4-7/h3-6,9-11,14,20H,17H2,1-2H3,(H,18,21)(H,23,24)/t9-,10-,11+,14-/m1/s1 checkY
  • Key:LSQZJLSUYDQPKJ-NJBDSQKTSA-N checkY
  (verify)
Amoxicillin BP

Amoxicillin (INN), formerly amoxycillin (BAN), tormoxin (in India), amoxycillin (cilamox) in Australia,[1] abbreviated amox, is a moderate-spectrum, bacteriolytic, β-lactam antibiotic used to treat bacterial infections caused by susceptible microorganisms. It is usually the drug of choice within the class because it is better absorbed, following oral administration, than other β-lactam antibiotics.

Amoxicillin is susceptible to degradation by β-lactamase-producing bacteria, which are resistant to a broad spectrum of β-lactam antibiotics, such as penicillin. For this reason, it is often combined with clavulanic acid, a β-lactamase inhibitor, and marketed under one name. This increases effectiveness by reducing its susceptibility to β-lactamase resistance.

Mode of action

Main article: Beta-lactam antibiotic

Amoxicillin acts by inhibiting the synthesis of bacterial cell walls. It inhibits cross-linkage between the linear peptidoglycan polymer chains that make up a major component of the cell walls of both Gram-positive and Gram-negative bacteria.

Formulations

Amoxicillin in trihydrate form is available as capsules, chewable and dispersible tablets plus syrup and pediatric suspension for oral use, and as the sodium salt for intravenous administration (although the IV formulation is not available in the United States[2]). It is one of the most common antibiotics prescribed for children, and the liquid forms are helpful where the patient might find it difficult to take tablets or capsules. It has two ionizable groups in the physiological range (the amino group in alpha-position to the amide carbonyl group and the carboxyl group). It is also a treatment for cystic acne.[3]

Modes of Delivery

Amoxicillin is usually taken orally, commonly as a tablet or a suspension, but can also be injected. There is recent research with mice that indicates successful delivery using intraperitoneally injected amoxicillin-bearing microparticles.[4]

Side-effects

Side-effects are as those for other beta-lactam antibiotics. Side-effects include nausea, vomiting, rashes, and antibiotic-associated colitis. Loose bowel movements (diarrhea) also may occur. Rarer, but patient-reported, side-effects include mental changes, lightheadedness, insomnia, confusion, anxiety, sensitivity to lights and sounds, and unclear thinking. Immediate medical care is required upon the first signs of these side-effects.

The onset of an allergic reaction to amoxicillin can be very sudden and intense - emergency medical attention must be sought as quickly as possible. The initial onset of such a reaction often starts with a change in mental state, skin rash with intense itching (often beginning in fingertips and around groin area and rapidly spreading), and sensations of fever, nausea, and vomiting. Any other symptoms that seem even remotely suspicious must be taken very seriously. However, more mild allergy symptoms, such as a rash, can occur at any time during treatment, even up to a week after treatment has ceased. For some people who are allergic to amoxicillin the side effects can be deadly.

Use of the amoxicillin/clavulanic acid combination for more than one week has caused mild hepatitis in some patients. Young children having ingested acute overdoses of amoxicillin manifested lethargy, vomiting and renal dysfunction.[5][6]

Nonallergic amoxicillin rash

See also: Stevens–Johnson syndrome

Somewhere between 3% and 10% of children taking amoxicillin (or ampicillin) show a late-developing (>72 hours after beginning medication and having never taken penicillin-like medication previously), often itchy rash, which is sometimes referred to as the "amoxicillin rash." The rash can also occur in adults.[7][8]

The rash is described as maculopapular or morbilliform (measles-like; therefore, in medical literature, it is called "amoxicillin-induced morbilliform rash"[9]). It starts on the trunk and can spread from there. This rash is unlikely to be a true allergic reaction, and is not a contraindication for future amoxicillin usage, nor should the current regimen necessarily be stopped. However, this common amoxicillin rash and a dangerous allergic reaction cannot easily be distinguished by inexperienced persons, and therefore a healthcare professional is often required to distinguish between the two.[10]

A nonallergic amoxicillin rash may also be an indicator of infectious mononucleosis: Some studies indicate approximately 80-90% of patients with acute Epstein Barr virus infection treated with amoxicillin or ampicillin develop such a rash.[11]

  • Nonallergic amoxicillin rash 8 days after first dose, 24 hours after rash began. Diagnosed by a pediatric resident at local university hospital.
    Nonallergic amoxicillin rash 8 days after first dose, 24 hours after rash began. Diagnosed by a pediatric resident at local university hospital.
  • Eight hours after first photo, individual spots have grown and begun to merge.
    Eight hours after first photo, individual spots have grown and begun to merge.
  • Twenty-three hours after first photo, the color appears to be fading, and much of rash has spread to confluence.
    Twenty-three hours after first photo, the color appears to be fading, and much of rash has spread to confluence.

Proprietary preparations

Novamoxin Prescription Drug - 500mg Amoxicillin Trihydrate

Amoxicillin is one of the semisynthetic penicillins discovered by Beecham scientists. The patent for amoxicillin has expired, thus amoxicillin is marketed under many trade names, including: Actimoxi, Alphamox, Amocla, AMK, Amoksibos, Amoxiclav Sandoz, Amoxidal, Amoxil, Amoxin, Amoksiklav, Amoxibiotic, Amoxicilina,Amoxidal, Apo-Amoxi, Augmentin (with clavulanic acid), Bactox, Betalaktam, Cilamox, Curam, Dedoxil, Dispermox, Duomox, E-Mox, Enhancin, Gimalxina, Geramox, Hiconcil, Isimoxin, Klavax, Klavocin, Klavox, Lamoxy,Largopen, Moxatag, Moxilen, Moxypen, Moxyvit, Nobactam, Novamoxin, Ospamox, Panklav (with clavulanic acid),Optamox, Pamoxicillin, Panamox, Polymox, Samthongcillin, Clamoxyl, Senox, Sinacilin, Trimox, Tolodina, Tormoxin (India), Wedemox, Wymox, Yucla, Zerrsox and Zimox.

Amoxicillin Interaction

Amoxicillin may interact with the following groups of drugs:

  • Allopurinol (gout treatment)
  • Birth control pills
  • Certain antibiotics
  • Cancer treatment (methotrexate)
  • Uricosuric drugs
  • Typhoid vaccine

References

  • GlaxoSmithKline (2006). "Amoxil - Prescribing information" (PDF). {{cite web}}: Unknown parameter |month= ignored (help)
  • Neal, M. J. (2002). Medical pharmacology at a glance (4th ed.). Oxford: Blackwell Science. ISBN 0-632-05244-9.
  • Pichichero ME (2005). "A review of evidence supporting the American Academy of Pediatrics recommendation for prescribing cephalosporin antibiotics for penicillin-allergic patients". Pediatrics. 115 (4): 1048–57. doi:10.1542/peds.2004-1276. PMID 15805383. {{cite journal}}: Unknown parameter |month= ignored (help)
  • Schmitt, Barton D. (2005). Your child's health: the parents' one-stop reference guide to symptoms, emergencies, common illnesses, behavior problems, healthy development (2nd ed.). New York: Bantam Books. ISBN 0-553-38369-8.
  • British National Formulary 45 March 2003

Footnotes

  1. ^ [1], Royal Australian College of General Practitioners Leaflet.
  2. ^ www.UpToDate.com
  3. ^ "Adolescent Acne: Management".
  4. ^ Amoxicillin bearing microparticles: potential in treatment of Listeria monocytogenes infection in Swiss albino mice, Bioscience reports immediate publication, 2010-08-05, manuscript BSR 20100027
  5. ^ Cundiff J, Joe S. Amoxicillin-clavulanic acid-induced hepatitis. Amer. J. Otolaryngol. 28: 28-30, 2007.
  6. ^ R. Baselt, Disposition of Toxic Drugs and Chemicals in Man, 8th edition, Biomedical Publications, Foster City, CA, 2008, pp. 81-83.
  7. ^ "Pretty severe itchy rash after Amoxicillin reaction - WrongDiagnosis.com". Forums.wrongdiagnosis.com. Retrieved 2010-11-13.
  8. ^ "Rash from Amoxicillin - Allergy". MedHelp. Retrieved 2010-11-13.
  9. ^ "Role of delayed cellular hypersensitivity and adhesion molecules in amoxicillin-induced morbilliform rashes". Cat.inist.fr. Retrieved 2010-11-13.
  10. ^ (Pichichero, 2005; Schmitt 2005)
  11. ^ Kagan, B (1977). "Ampicillin rash". Western Journal of Medicine. 126 (4): 333–335. PMC 1237570. PMID 855325.
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