A potent prescription

18 February 2022

Making assumptions can have serious consequences, as this cautionary case illustrates...

A patient visited a dental practice complaining of sore gums. His regular dentist was not at work on that day and the receptionist informed the senior partner of the problem.

The dentist did not bother to examine the patient but noticed from the record card that he had suffered from periodontal disease for a long time and informed him verbally that this was likely to be a recurrence of the same problem. He gave the patient a prescription of metronidazole.

Unfortunately, the patient’s medical history was not checked and in fact he was on long-term high-dose warfarin therapy. The antibiotic potentiated the action of the warfarin and led to the patient being hospitalised and needing an emergency transfusion.

The partner sought advice and it was agreed that he would arrange to see the patient for review and explain the problems that could result from a prescription of this type of antibiotic despite it being a drug commonly used to treat periodontal disease. The patient took no further action.

Learning points

This case illustrates the importance of a clinical examination to confirm that the prescription was a justified treatment and also the need for careful consideration of the patient’s medical history for possible drug interactions.


These case studies are based on real events and provided here as guidance. They do not constitute legal advice but are published to help members better understand how they might deal with certain situations. This is just one of the many benefits Dental Protection members enjoy as part of their subscription. 
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