Been taking amoxicillin on and off for frequent tonsillitis. my doctor just switched me to augmentin (amoxicillin and clavulanate). why did she switch, if the amoxicillin works?

Clavulinic acid: Some believe that beta-lactamase producing organisms in the throat can protect streptococcus pyogenes from the bactericidal effects of amoxicillin. Augmentin (amoxicillin and clavulanate) which contains clavulinic acid which prevents the beta-lactamases from degrading the Amoxicillin may allow it to kill the streptococcus causing the tonsillitis.

Neither: In general, we don't treat sore throats, including tonsillitis, with antibiotics unless tests show it's caused by strep. That's because the condition is usually vital, not bacterial. When it is due to strep, Amoxicillin is the preferred drug. Augmentin (amoxicillin and clavulanate) will work, but is more likely to cause diarrhea.