Pharmacy Pearl 30 May 2001

An adult patient presents to the window with a prescription for Augmentin® 500mg po TID for sinusitis. Because of supply problems, you're out of the 500mg tablets but do have the 250mg tablets. The technician wants to dispense the 250mg tablets with the directions 2 tablets (500 mg) po TID.

Do you concur or not? Why or why not?

SELECT here for discussion

No. The 250mg and the 500mg oral tablets both contain the same amount of clavulanic acid, 125mg, the beta lactamase inhibitor. Doubling the 250mg tablets doubles not only the amoxicillin component but the clavulanic acid component as well. Excess clavulanic acid is associated with a greater incidence of gastrointestinal side effects such as nausea, vomiting, and diarrhea.

One option in this case would be to use one Augmentin 250mg tablets along with one Amoxicillin 250mg capsule. This combination would yield the same ingredients and amounts as the Augmentin 500mg tablets. This combination has been used as a cost saving measure in some MTFs. The decision to use this strategy must be weighed against a possible decrease in compliance by the patient because of an increased number of tablets/capsules per day. The chewable Augmentin 250mg tablets can be doubled for the correct 500mg/125mg dose since the chewable tablets only have 62.5mg of clavulanic acid per tablet.

Diarrhea is a problem with both amoxicillin and Augmentin. Taking/giving the drug with food or meals may help decrease the incidence and/or severity.

Remember, penicillin resistance in Streptococci is from a change in penicillin binding protein and NOT production of beta lactamase. In patients with penicillin resistant Strep infections the drug of choice (barring other contraindications) would be an extended spectrum fluoroquinolone (i.e. levofloxacin).

This Pearl is meant for academic and educational purposes only. This Pearl is meant to raise important points regarding the safe and cost-effective pharmacotherapy of patients. It is not meant to be the definitive reference for the treatment or prophylaxis of various diseases. Although every effort is taken to ensure this Pearl is correct and factual, errors may occur. The Pharmacoeconomic Center assumes no liability for incorrect information or harm that may occur from the use of the information included in this Pearl.