Amoxicillin adverse effects

In patients with significant bacteriuria, symptomatic or asymptomatic, treatment is recommended in order to avoid possible complications during the pregnancy. Therapy should consist of an agent with a relatively low adverse-effect potential (a sulfonamide, cephalexin, amoxicillin, amoxicillin/clavulanate, nitrofurantoin) administered for 7 days. 

There are a number of factors that limit the effectiveness of regimens designed to eradicate H. pylori. The first, antibiotic resistance, is seen with metronidazole and clarithromycin but has not been reported with bismuth, amoxicillin, or tetracycline. Second, mild adverse effects (eg, diarrhea, metallic taste, black stools) do occur in approximately 30% to 50% of patients. Therefore, shorter treatment periods in this group of patients may be better tolerated. 

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

Amoxicillin (t) 1 h previously known as amoxycillin) is a structural analogue of ampicillin (below) and is better absorbed from the gut (especially after food), and for the same dose achieves approximately double the plasma concentration. Diarrhoea is less frequent with amoxicillin than with ampicillin. The oral dose is 250 mg 8-hourly a parenteral form is available but offers no advantage over ampicillin. For oral use, however, amoxicillin is preferred because of its greater bioavailability and fewer adverse effects. 

Adverse effects. Ampicillin may cause diarrhoea but the incidence (12%) is less with amoxicillin. Ampicillin and amoxicillin are the commonest antibiotics to be associated with Clostridium difficile diarrhoea, although this is related to the frequency... 

In two randomized trials in pregnant women with cervical Chlamydia trachomatis infection, women were randomized to oral amoxicillin 500 mg tds for 7 days or oral azithromycin 1 g in a single dose (42,43). The two drugs had similar efficacy. Adverse effects were common in both groups 40% of those who took azithromycin reported moderate to severe gastrointestinal adverse effects compared with 17% of those who took amoxicillin. 

The MACH-2 study has assessed the role of omeprazole in triple therapy in 539 patients with duodenal ulcers associated with H. pylori (3). The addition of omeprazole resulted in significantly higher eradication rates (over 90%) than antibiotics alone (amoxicillin plus clarithromycin about 25% clarithromycin plus metronidazole 70%), and reduced the impact of primary resistance to metronidazole. About one-third of the patients who took amoxicillin reported diarrhea/loose stools. The frequency of taste disturbance was dose-dependent with clarithromycin. Increased liver enzymes were more commonly reported in those taking metronidazole. The addition of omeprazole did not increase the frequency of reported adverse effects. 

The DU-MACH study assessed the efficacy of two omeprazole-based triple therapies (omeprazole, amoxicillin, clarithromycin versus omeprazole, metronidazole, clarithromycin) given for 1 week to 149 patients for eradicating H. pylori, healing duodenal ulcers, and preventing ulcer relapse over 6 months after treatment (4). Both regimens achieved high eradication rates (about 90%) and were well tolerated. Adverse effects were similar in the two groups, and included diarrhea, taste disturbance, headache, nausea, and dyspepsia. 

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. 

Dual therapy (omeprazole plus clarithromycin) for 2 weeks has been compared with triple therapy (omeprazole plus amoxicillin and clarithromycin) for 1 week in the eradication of H. pylori in 145 patients with duodenal nlcers (7). Triple therapy was significantly more effective in eradicating H. pylori (71 versus 48%). There were no significant differences in comphance or adverse effects. The most freqnent adverse effects were metallic taste and nansea in the dnal-therapy gronp and metalhc taste, mild abdominal pain, and diarrhea in the triple-therapy group. 

Quadruple therapy (omeprazole, amoxicUhn, roxithromycin, and metronidazole for 1 week) has been studied in an open trial in 169 patients with H. pylori (8). This regimen achieved an eradication rate of 92%. It was also beneficial in patients infected with pretreatment resistant strains to the antibiotics, in which cases the eradication rates achieved (over 90%) were similar to eradication rates in patients infected with sensitive strains. Compliance was good and there was only one serious adverse effect, anaphylaxis, probably due to amoxicillin. Frequent adverse effects were abdominal distension (10%), glossitis (9%), and diarrhea (8%). 

Sucralfate 1 g tds in combination with amoxicillin 500 mg tds and clarithromycin 400 mg bd for 2 weeks was as effective as a combination of lansoprazole 30 mg bd plus amoxicillin 500 mg tds and clarithromycin 400 mg bd for 2 weeks for H. pylori eradication in a randomized, multicenter trial in 150 patients (9). There was no significant difference in adverse effects between the two groups. Diarrhea, abdominal pain, glossitis, and taste disturbance were the adverse effects commonly reported. 

In an open trial, 7-day triple therapy with omeprazole 30 mg bd, amoxicillin 500 mg tds, and clarithromycin 400 mg bd was safe and effective in eradicating H. pylori in 12 of 13 patients undergoing hemodialysis (10). There were adverse effects in two patients (compared with three of 27 patients not undergoing hemodialysis) and treatment had to be discontinued in one, owing to severe nausea and vomiting. 

In a randomized, controlled trial in 120 patients supplementation with inactivated Lactobacillus acidophilus tds significantly improved the efficacy of a standard 7-day regimen with rabeprazole 20 mg bd, clarithromycin 250 mg tds, and amoxicillin 500 mg tds (12). There was no significant difference in adverse effects between the two groups. Those reported were abdominal pain, nausea, and diarrhea. 

In the eradication of Helicobacter pylori, metronidazole plus bismuth is effective, but causes more adverse effects than omeprazole plus amoxicillin plus either clarithromycin or metronidazole. 

Assess and monitor patients for potential adverse effects, especially those associated with metronidazole, clarithromycin, and amoxicillin. 

Therapy should consist of an agent administered for 7 days that has a relatively low adverse-effect potential and is safe for the mother and baby. The administration of a sulfonamide, amoxicillin, amoxicillin-clavulanate, cephalexin, or nitrofurantoin is effective in 70% to 80% of patients. Tetracyclines should be avoided because of teratogenic effects, and sulfonamides should not be administered during the third trimester because of the possible development of kernicterus and hyperbilirubinemia. In addition, the available fluoroquinolones should not be given because of their potential to inhibit cartilage and bone development in the newborn. A follow-up urine culture 1 to 2 weeks after completing therapy and then monthly until gestation is complete is recommended. 

Peak plasma concentrations of amoxicihin (amoxil, others) are twice those of ampiciUin after oral administration of the same dose. Food does not interfere with absorption. Perhaps because of its more complete absorption, the incidence of diarrhea with amoxicillin is less than that with ampicilhn. The incidence of other adverse effects is similar. While the tj of amoxidlhn is similar to that for ampiciUin, effective concentrations of orally administered amoxicihin are detectable in the plasma for twice as long as with ampicUhn because of its more complete absorption. About 20% of amoxidftin is protein-bound in plasma. Most of the antibiotic is excreted in an active form in the mine. 

In a double-blind, randomized, multicenter trial in 302 children, a 10-day course of erythromycin estolate (40 mg/kg/day in two doses) was as safe and effective as amoxicillin (50 mg/kg/day in two doses) in acute otitis media. Treatment-related adverse events occurred in 5.3% of patients given erythromycin and in 7.3% of patients given amoxicillin (4). 

The concentrations of licensed medications may be too high, necessitating further manipulation in the form of dilution with an excipient. However, when the concentration is low, the dose volume may be too large for some children. The excipients in many liquid formulations may not be suitable for selected patient groups. For example, the propylene glycol content in amprenavir liquid formulation makes it unsuitable for children under 4 years of age. Severe delayed-onset hypersensitivity reaction was associated with formulation of amoxicillin liquid the reaction may have been caused by the exicipent (Chopra et ai, 1989). Sweeteners, dyes and other excipients may cause adverse reactions and should be identified and restricted in paediatric formulations (Kumar et ai, 1996). Some clinical studies have been directed to ascertain the effect of drug concentration and frequency of... 

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