Fatal anaphylaxis to intravenous coamoxiclav: A case series

Introduction: Fatal anaphylaxis to co­amoxiclav is rarely reported. We report three fatalities directly attributable to intravenous co­ amoxiclav administration. Case Report: Three patients with no prior history of drug allergy developed fatal anaphylaxis following intravenous administration of co­amoxiclav. Notably two of the three cases had been administered co­amoxiclav in the weeks preceding the fatal event. Each patient also had a factor associated with increased severity of anaphylaxis. Despite timely, appropriate and aggressive management of the anaphylactic reactions each case had a fatal outcome. Conclusion: Fatal anaphylaxis to co­amoxiclav is uncommon. These cases are typical of the rapid symptom onset of type I hypersensitivity to parenteral medication. Each incident occurred within a four­year time frame in a relatively small geographic area. This is out of proportion to 10 other fatalities related to amoxicillin containing medications occurring in the UK over a 47­year period. The clinical diagnoses were supported by elevations in serum mast cell tryptase. Assessment of drug allergy commonly relies on clinical history supported by skin and intradermal testing. Risk assessment algorithms incorporating such testing techniques are unlikely to have altered outcome in these cases. These cases indicate that anaphylaxis to co­amoxiclav may have a catastrophic outcome despite immediate management. Such cases may be under reported and more prevalent than previously indicated. All staff administering parenteral co­amoxiclav should be aware of the risk of anaphylaxis even in patients with a prior history of tolerance of the drug.