Amoxicillin versus ...

Amoxicillin vs. Amoxicillin Clavulanate (Augmentin)

Side effects

Recent Italian study5 found that skin reactions occur more frequently with amoxicillin than with amoxicillin/clavulanic acid. The incidence of gastrointestinal, hepatic and haematological side effects is significantly higher for amoxicillin/clavulanic acid. Also, Amoxicillin/clavulanic acid seems to be associated with a higher risk of Stevens-Johnson syndrome, purpura and hepatitis than amoxicillin alone.

Recurrent Otitis media

For recurrent otitis media (middle ear infection) amoxycillin/clavulanate for 7 days is comparable to amoxycillin for 10 days.

A double-blind study14 with parallel groups, compared treatment with amoxicillin/clavulanate suspension (Spektramox) for 7 days with amoxicillin suspension (Imacillin) for 10 days. Amoxicillin/clavulanate and amoxicillin showed equally high, satisfactory treatment results, i.e. more than a 90% response. Similarly, there was no statistically significant difference between the groups at the second follow-up visit (about 30 days after start of treatment). Elimination of the initially occurring pathogens was equal in the two study groups with the exception of Branhamella catarrhalis which was eliminated to a significantly higher extent with amoxicillin/clavulanate. Both drugs were well tolerated.

Secretory Otitis media

Amoxicillin/clavulanate may have some advantages over amoxicillin in the treatment of otitis media with effusion (fluid in the middle ear, or "Glue ear").

Results of comparative study of Augmentin and amoxicillin trihydrate for otitis media with effusion3. Amoxicillin Amoxicillin-
Effusion free rate at day 10 following study entry 32%
(16 of 50 patients)
(29 of 56 patients)
Effusion free rate at 4 weeks following study entry 51.1%
(23 of 45 patients)
(26 of 50 patients)
Recurrence of effusion by the 16-week 63.2%
(12 of 19 patients)
(8 of 22 patients)

Respiratory tract infections (pneumonia, bronchitis, bronchiectasis)

Amoxicillin plus clavulanic acid is more effective than amoxicillin in the treatment of respiratory infections. Amoxicillin/clavulanic acid is superior to amoxicillin against strains of Branhamella catarrhalis, E. coli, coagulase-negative staphylococci and K. pneumoniae.

A Croatian study6 compared amoxicillin/clavulanic acid and amoxicillin in the treatment of respiratory tract infections. Leucocytosis and macroscopic purulence of sputum significantly improved with amoxicillin/clavulanate therapy while with amoxicillin there was no significant improvement. With respect to the presence of fever, there was no significant difference between two groups. The overall symptoms improvement and bacteriological response (eradication of bacteria) were very good and good in 88.5% of patients treated with amoxicillin/clavulanate compared to 75% of those receiving amoxicillin.


Both amoxicillin/clavulanate and amoxicillin are equally effective in the treatment of acute sinusitis.

A double-blind, placebo-controlled study1 compared the relative effectiveness of amoxicillin and Augmentin, in the treatment of acute maxillary sinusitis in children 2 to 16 years of age. 93 children were evaluated: 30 received amoxicillin, 28 received amoxicillin/clavulanate potassium, and 35 received placebo. Clinical assessment was performed at three and ten days. On each occasion, children treated with an antibacterial were more likely to be cured than children receiving placebo. The overall cure rate was 67% for amoxicillin, 64% for amoxicillin/clavulanate potassium, and 43% for placebo.

Amoxicillin vs. Clarithromycin (Biaxin)

Clarithromycin and amoxicillin appears to have comparable effectiveness in the treatment of sinusitis7.

Results of comparison of clarithromycin and amoxicillin in the treatment of acute maxillary sinusitis7. Amoxicillin Clarithromycin
Regimen 500 mg 3 times daily for 7 to 14 days 500 mg 2 times dailty for 7 to 14 days
Clinical success rate (based on direct observation of the patient) 89% 91%
Roentgenographic success rate 92% 78%
Dropout rates 4% 3%
Adverse effects mild gastrointestinal side effects


Amoxicillin and clarithromycin are equally effective in the treatment of community-acquired pneumonia in children.

In a randomized clinical trial8 the mean hospital stay in patients treated with amoxicillin was 3.3 days and with clarithromycin was 3.2 days. Ninety-seven percent patients in both treatment groups achieved symptoms improvement.

Otitis media

Clarithromycin and amoxicillin are similarly effective in the treatment of acute ear infection (otitis media).

Single blind, randomized, multicenter clinical trial2 compared the safety and efficacy of clarithromycin and amoxicillin suspensions (each given for 7 to 10 days) in the treatment of acute otitis media in children 1 to 12 years of age. Clinical success (cure and symptoms improvement) rates at 0 to 4 days posttreatment were 93% for clarithromycin and 90% for amoxicillin. Altogether 17 children (10 receiving clarithromycin, 7 receiving amoxicillin) experienced some side effect. Gastrointestinal disorders were the most common complaint. No clinically significant differences in laboratory tests were found between the groups.

Erythema migrans (the rash characteristic of Lyme disease)

Clarithromycin works a little better than amoxicillin in the treatment of children with solitary erythema migrans.

In the comparative study16 of children with solitary erythema migrans 66 patients received clarithromycin and 69 amoxicillin. The mean duration of erythema migrans after the beginning of treatment was 4 days in both groups. Associated symptoms during treatment were present for 7 days in patients treated with clarithromycin and for 10 days in patients receiving amoxicillin. Minor manifestations of Lyme borreliosis were identified in 11 (22.0%) of 50 patients receiving clarithromycin, and in 16 (29.6%) of 54 patients receiving amoxicillin who remained in the study during the entire observation period. Major manifestations of Lyme borreliosis were not identified in any patient treated with clarithromycin, while there were 2 (3.7%) patients treated with amoxicillin. Side effects were identified in 24.2% patients receiving clarithromycin and 28.1% patients treated with amoxicillin.

Amoxicillin vs. Cefuroxime axetil (Ceftin)

Lyme disease

Both amoxicillin and cefuroxime axetil are safe and effective for Lyme disease.

Randomized, unblinded study4 compared 2 regimens of cefuroxime axetil (20 mg/kg/d and 30 mg/kg/d) with amoxicillin (50 mg/kg/d), each given for 20 days. At the completion of treatment, there was total resolution of erythema migrans in 67% of the amoxicillin group, 92% of cefuroxime group (20 mg/kg/d), and 87% of cefuroxime group (30 mg/kg/d), and resolution of constitutional symptoms occurred in 100%, 69%, and 87%, respectively. Mild diarrhea occurred in a small number of participants in each group (1 patient was diagnosed and treated for Clostridium difficile-associated diarrhea, which occurred after completing the full course). No hypersensitivity reactions occurred.


Both amoxicillin and cefuroxime are similarly effective in the improvement of bronchitis symptoms. However, amoxicillin therapy results in a significantly higher relapse rates.

In an investigator-blind, randomised, parallel group, multicentre study9 the two antibacterials had roughly similar efficacy:

Results of investigator-blind, randomised, parallel group, multicentre study of amoxicillin and cefuroxime in the treatment of bronchitis9 Amoxicillin Cefuroxime
Regimen 250 mg 3 times daily 250 mg 2 times daily
Clinical cure or improvement rate 24-72 hours after completion of the antibiotic treatment 80.4%
(123 of 153 patients)
(109 of 143 patients)
Clinical relapses during the 4-week follow-up period following the end of treatment 20.8%
(16 of 77 patients)
(4 of 68 patients)
Adverse events mild and transient

Otitis media

Cefuroxime axetil has comparable efficacy to amoxicillin in the treatment of children with middle ear infection and both are well tolerated.

In a multicentre general practice study10 of cefuroxime axetil suspension and amoxycillin syrup in the treatment of acute otitis media the overall cure or improvement rate was 94.3% for patients treated with cefuroxime axetil and 94.5% for those receiving amoxicillin. Some Streptococcus pneumoniae and Moraxella catarrhalis strains were resistant to amoxicillin.

Amoxicillin vs. Minocycline


Minocycline may be somewhat more effective than amoxicillin in the treatment of acute bacterial sinusitis.

In a comparative study15 after 11 days of antibacterial therapy, clinical cure or improvement and bacterial eradication were evident in 100% of the patients treated with minocycline and in 95% of the patients treated with amoxicillin. Roentgenographic results indicated clearing or improvement in 91% of the minocycline recipients and in 70% of those who received amoxicillin.

Amoxicillin vs. Doxycycline

Lyme disease (Erythema migrans)

Amoxycillin plus probenecid and doxycycline for 21 days are equally effective for treatment of Lyme disease. Both antibacterials have in-vitro sensitivity of Borrelia burgdorferi, the necessary tissue penetration and pharmacokinetics.

In a randomised prospective study11 comparing amoxycillin/probenecid with doxycycline both regimens were equally effective for treatment of erythema migrans. Mild fatigue or arthralgia were the only post-treatment complaints, which resolved within 6 months. None of the patients needed further antibacterial treatment for Lyme borreliosis.


Doxycycline and amoxicillin are equally effective for treating chlamydial and nonchlamydial cervicitis.

In a randomized trial12 of doxycycline versus amoxicillin in the treatment of mucopurulent cervicitis patients were followed up for 3 months, and the effect of treatment was assessed by clinical (presence of endocervical mucopus, cervicitis severity score, and number of polymorphonuclear leukocytes on Gram-stained smears of endocervical secretions) and microbiologic criteria. Doxycycline and amoxicillin were equally effective for treating chlamydial and nonchlamydial cervicitis. However, endocervical mucopus was still present in 18% of the patients in both groups after 2 months, and in 23% of the doxycycline group and 33% of the amoxicillin group after 3 months of therapy. The cause of persistent/recurrent mucopus after antimicrobial treatment was not explained by relapse or reinfection with Chlamydia trachomatis, Neisseria gonorrhoeae, genital mycoplasmas, or Gardnerella vaginalis, but persistence was associated with the degree of cervical ectopy.

Respiratory tract infections

Doxycycline seems to be superior to amoxicillin in respiratory tract infections.

Clinical observational study13 found statistically significant better response in those patients with acute and acute-on-chronic bronchitis who were treated with doxycycline. It is possible that this may have been related to a local upsurge in mycoplasma infection at the time of the study.


Further reading

  • 1. Wald ER, Chiponis D, Ledesma-Medina J. Comparative effectiveness of amoxicillin and amoxicillin-clavulanate potassium in acute paranasal sinus infections in children: a double-blind, placebo-controlled trial. Pediatrics. 1986 Jun;77(6):795-800. PubMed
  • 2. Pukander JS, Jero JP, Kaprio EA, Sorri MJ. Clarithromycin vs. amoxicillin suspensions in the treatment of pediatric patients with acute otitis media. Pediatr Infect Dis J. 1993 Dec;12(12 Suppl 3):S118-21. PubMed
  • 3. Chan KH, Mandel EM, Rockette HE, Bluestone CD, Bass LW, Blatter MM, Breck JM, Reisinger KS, Wolfson JH, Wucher FP, et al. A comparative study of amoxicillin-clavulanate and amoxicillin. Treatment of otitis media with effusion. Arch Otolaryngol Head Neck Surg. 1988 Feb;114(2):142-6. PubMed
  • 4. Eppes SC, Childs JA. Comparative study of cefuroxime axetil versus amoxicillin in children with early Lyme disease. Pediatrics. 2002 Jun;109(6):1173-7.
  • 5. Salvo F, Polimeni G, Moretti U, Conforti A, Leone R, Leoni O, Motola D, Dusi G, Caputi AP. Adverse drug reactions related to amoxicillin alone and in association with clavulanic acid: data from spontaneous reporting in Italy. J Antimicrob Chemother. 2007 Jul;60(1):121-6.
  • 6. Music E, Kumelj M, Prlja D, Paulin A, Potokar T. Comparison of amoxicillin and amoxiclav in the therapy of respiratory infections. Plucne Bolesti. 1989 Jul-Dec;41(3-4):187-92. PubMed
  • 7. Calhoun KH, Hokanson JA. Multicenter comparison of clarithromycin and amoxicillin in the treatment of acute maxillary sinusitis. Arch Fam Med. 1993 Aug;2(8):837-40. PubMed
  • 8. Aurangzeb B, Hameed A. Comparative efficacy of amoxicillin, cefuroxime and clarithromycin in the treatment of community-acquired pneumonia in children. J Coll Physicians Surg Pak. 2003 Dec;13(12):704-7. PubMed
  • 9. Shah SH, Shah IS, Turnbull G, Cunningham K. Cefuroxime axetil in the treatment of bronchitis: comparison with amoxycillin in a multicentre study in general practice patients. Br J Clin Pract. 1994 Jul-Aug;48(4):185-9. PubMed
  • 10. Brodie DP, Griggs JV, Cunningham K. Comparative study of cefuroxime axetil suspension and amoxycillin syrup in the treatment of acute otitis media in general practice. J Int Med Res. 1990 May-Jun;18(3):235-9. PubMed
  • 11. Dattwyler RJ, Volkman DJ, Conaty SM, Platkin SP, Luft BJ. Amoxycillin plus probenecid versus doxycycline for treatment of erythema migrans borreliosis. Lancet. 1990 Dec 8;336(8728):1404-6. PubMed
  • 12. Paavonen J, Roberts PL, Stevens CE, W?lner-Hanssen P, Brunham RC, Hillier S, Stamm WE, Kuo CC, DeRouen T, Holmes KK, et al. Randomized treatment of mucopurulent cervicitis with doxycycline or amoxicillin. Am J Obstet Gynecol. 1989 Jul;161(1):128-35. PubMed
  • 13. Richards JG. Doxycycline and amoxycillin in respiratory infections: a comparative assessment in general practice. Curr Med Res Opin. 1980;6(6):393-7. PubMed
  • 14. Stenstrom C, Lundgren K, Ingvarsson L, Bertilson SO. Amoxycillin/clavulanate versus amoxycillin in recurrent otitis media and therapeutic failure in children. Acta Otolaryngol. 1991;111(1):120-9. PubMed
  • 15. Mattucci KF, Levin WJ, Habib MA. Acute bacterial sinusitis. Minocycline vs amoxicillin. Arch Otolaryngol Head Neck Surg. 1986 Jan;112(1):73-6. PubMed
  • 16. Nizič T, Velikanje E, Ružić-Sabljić E, Arnež M. Solitary erythema migrans in children: comparison of treatment with clarithromycin and amoxicillin. Wien Klin Wochenschr. 2012 Jul

Published: March 31, 2008
Last updated: February 09, 2017


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