Prior to the 2008 guidelines, clinicians wrote 10 900 prescriptions a month for these prophylactic drugs, and most prescriptions (90%) were written by dentists.
The rate of prescriptions fell off exponentially after the guidelines were introduced, so that by the March 2013, the average number of prescriptions fell by almost 90% (to 1307 a month).
At the same time, the number of cases of endocarditis per month rose by 0.11 cases per 10 million people in England, and by March 2013 this amounted to an extra 35 cases per month. There were 420 additional hospitalizations and 18 additional deaths related to endocarditis a year.