Rashes amoxicillin

Amoxicillin 80-90 mg/kg per day in 2-3 doses (adult 875 mg twice daily) Nausea, vomiting, diarrhea, rash Drug of choice for AOM experts recommended high-dose over conventional doses (40-45 mg/kg per day)... 

T effects W probenecid, disulfiram, T risk of rash W/ allopurinol, effects OF OCP, effects W/ tetracyclines, chloramphenicol EMS See Amoxicillin Amphotericin B (Amphecin) [Antifungal/Pelyene Macrolide]... 

Ampicillin and amoxicillin are not recommended for blind treatment of sore throat because of their propensity to cause maculopapular rashes in patients... 

ALLOPURINOL AMOXICILLIN, AMPICILLIN Possible t risk of rash with amoxicillin and ampicillin (over 20% incidence in one study) Uncertain Reassure patients that the rash is unlikely to have clinical significance... 

Drugs can give diagnostic clues, e.g. ampicillin and amoxicillin causing rash in infectious mononucleosis — a diagnostic adverse effect, not a diagnostic test. 

Patients with chronic lymphatic leukemia or with concurrent infection with Epstein-Barr virus or HIV have an increased frequency of ampicillin- and amoxicillin-associated rashes (280). 

Ranitidine 300 mg bd and omeprazole 20 mg bd have been compared as components of triple therapies (combining them with either amoxicillin plus clarithromycin or amoxicillin plus metronidazole) in 320 patients with H. pylori (5). Omeprazole and ranitidine combined with two antibiotics for 1 week were equally effective in eradicating H. pylori. This result questions the role of profound acid suppression in eradication. There was no difference in the reported adverse effects, which included nausea, vomiting, diarrhea, metallic taste, skin rashes, and headache. 

In a similar study in 221 patients with peptic ulcer disease associated with H. pylori, rabeprazole has been compared with omeprazole and lansoprazole (combining them with amoxicillin plus clarithromycin for 1 week) (6). Rabeprazole was as effective as omeprazole and lansoprazole in eradicating H. pylori (84-88% each). There were no differences in reported adverse events. Common adverse effects were soft stools, glossitis, taste disturbances, and skin rashes. 

Mechanisms of non-immediate reactions are unclear but may be immunological and non-immunological. Delayed reactions of the IgE type are known (131). Aminopenicillins seem to be an important cause of non-immediate reactions (132-134). The morbilliform rash that begins 1-10 days after amoxicillin can be caused by a delayed cell-mediated immune reaction (135) as can fixed drug eruptions (136,137), toxic epidermal necrolysis (138-140), bullous erythroderma (141), and contact eczema (142). Investigation of these disorders should include delayed readings of skin tests (135). In patients with chronic urticaria, penicillin allergy was demonstrated by cutaneous tests. 

Although several reports have described fixed rashes due to amoxicillin, palmar exfoliation has rarely been described (164). 

The incidence of skin rashes in patients taking either ampicillin or amoxicillin is increased by allopniinoL... 

A retrospective search through the records of 1324 patients, 67 of whom were taking allopurinol and ampicillin, found that 15 of them (22%) developed a skin rash compared with 94 (7.5%) of the patients not taking allopurinol. The types of rash were not defined. Another study found that 35 out of 252 patients (13.9%) taking allopurinol and ampicillin developed a rash, compared with 251 out of 4434 (5.9%) taking ampicillin alone. A parallel study revealed that 8 out of 36 patients (22%) taking amoxicillin and allopurinol developed a rash, whereas only 52 out of 887 (5.9%) did so when taking amoxicillin alone. ... 

An established interaction of limited importance. There would seem to be no strong reason for avoiding concurrent use, but prescribers should recognise that the development of a rash is by no means unusual. Whether this also occurs with penicillins other than ampieillin or amoxicillin is uncertain, and does not seem to have been reported. 

Ben Fred] N, Aouam K, Chaabane A, Toumi A, Ben Rhomdhane F, Boughattas N, Chakroun M. H5ipersensitiv-ity to amoxicillin after drug rash with eosinophilia and systemic symptoms (DRESS) to carbamazepine and allopurinol a possible co-sensitization. Br J Clin Pharmacol 2010 70(2) 273-6. 

Fig. 5.2 Erythematous rash on a patient s neck (a), arms, and hands (b) following oral challenge with amoxicillin. The patient showed a negative intradermal test to the drag and responded on the last oral challenge dose of amoxidl-lin. (Photographs courtesy of Dr P. A. J. Russo and Dr J. S. Fok, Department of Clinical Immunology and AUeigy, Royal Adelaide Hospittd, Adelaide)...

Skin The increased risk of a maculopapu-lar rash after the use of amoxicillin in patients with infectious mononucleosis has been illustrated by the case of a 24-year-old woman who developed such a rash after a single dose of amoxicillin 500 mg [89 ]. Reactivation of human herpesvirus 6 may also lead to skin reactions, as suggested by a series of seven cases of amoxicillin-induced flares in patients with drug reactions with eosinophilia and systemic symptoms (DRESS) due to other drugs in in vitro studies in a human T lymphoblas-toid MT4 cell line, amoxicillin increased replication of human herpesvirus 6 [90 ]. 

Couto M, Duarte C, Geraldes A, Medeiros C, Ines L, Malcata A. Rash, fever and proteinuria after amoxicillin in a SLE patient. Acta Reumatol Port 2009 34(3) 526-30. 

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