Amoxicillin versus ...

Based on "Antibiotic and Chemotherapy"
written by Roger G. Finch

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.

Results of double-blind study14 with parallel groups of Amoxycillin/clavulanate versus amoxycillin for recurrent otitis media. Amoxicillin suspension (Imacillin) Amoxicillin-
clavulanate suspension (Spektramox)
Treatment results More than 90% response
Treatment results after about 30 days after start of antibiotic therapy Similar
Elimination of the initially occurring pathogens Equal
Elimination of Branhamella catarrhalis   Significantly higher elimination rate
Tolerability Equal

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.

Results of double-blind, placebo-controlled study1 comparing the relative effectiveness of amoxicillin and Augmentin for acute maxillary sinusitis in children Amoxicillin Amoxicillin-
Cure rate 67% 64%

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 amoxicillin recipients.

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 cervicitis12.

Results of randomized trial12 of doxycycline versus amoxicillin in the treatment of mucopurulent cervicitis Amoxicillin Doxycycline
Presence of endocervical mucopus after 2 months 18%
Presence of endocervical mucopus after 3 months 33% 23%

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
  • 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
  • 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. PubMed
  • 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
  • 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

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


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