PRESCRIBING
CongratulationsSir, we congratulate N. Beacher et al. for bringing the antibiotic-associated complications of Clostridium difficile-associated disease (CDAD) to the attention of dentists. 1 Although their coverage of the topic was comprehensive, there are recently published data specifically related to the dental use of amoxicillin and clindamycin for the prevention of infective endocarditis and the associated incidence of CDAD. 2 We surveyed yellow card adverse reaction reports between 1963 and 2014 for all prescriptions of a single 3 g oral dose of amoxicillin or a single 600 mg oral dose of clindamycin. The adverse reaction rate for amoxicillin was very low with zero fatal and 22.62 non-fatal adverse reactions reported per million prescriptions -of which 40% were allergy-related and 15% could have been CDAD-related. In contrast, the adverse reaction rate with clindamycin was much higher with 12.6 fatal and 149.1 non-fatal adverse reactions per million prescriptions with all but one of the fatal reactions due to CDAD and the majority of the non-fatal reactions (57%) likely due to CDAD with only 22% allergy-related. While demonstrating that CDAD can occur with amoxicillin, our data suggest that a single 3 g oral dose used for antibiotic prophylaxis is extremely safe. In contrast, a single oral dose of clindamycin appears to cause CDAD with a much higher frequency and severity, including death, than amoxicillin. Indeed, the propensity for a single dose of clindamycin to cause CDAD appeared to be similar to that of more prolonged courses of clindamycin used for treating infections. This was somewhat unanticipated as it had previously been thought that a single dose would be unlikely to predispose to the development of CDAD.M All anti-thrombotic agents produce a bleeding tendency and may cause postoperative bleeding. Dental preventive care is thus especially important in order to minimise the need for surgical intervention. In general, anti-thrombotic agents should be stopped before surgery only where the risk of post-operative bleeding is high (eg major surgery) or where the consequences of even minor bleeding are significant (eg retinal and intracranial surgery) though, for other minor surgery, drug dose reductions are rarely needed and indeed may put the patient at risk from thromboses which can be lethal. 1 This should be discussed with the patient, who also must be warned of the risk of intra-and post-operative bleeding and intra/extra-oral bruising.The two main classes of anti-thrombotic drugs are anticoagulants and antiplatelet drugs. Oral anticoagulants include:• Vitamin K antagonists (VKAs -such as warfarin/coumarins) • Newer oral anticoagulants (NOACssuch as dabigatran). The latter, such as direct thrombin inhibitors (DTI) (gatrans) and anti-Xa (xabans), target respectively the single coagulation enzymes thrombin (dabigatran) or factor Xa (apixaban, rivaroxaban, and edoxaban). In contrast to warfarin, NOACs have less thrombotic events and lower rates of major bleeding events and do not requir...
