31st August 2018, Volume 131 Number 1481

Flucloxacillin-warfarin interaction: an under-appreciated phenomenon

Sub-therapeutic anticoagulation attributed to flucloxacillin-warfarin interaction has been described in individual case reports.

The authors of this report encountered one such case in their hospital-in-the-home service in Brisbane. Review of the records of this service revealed a total of four examples of patients who appeared to suffer from such a flucloxacillin-warfarin interaction. In all 4 cases there was a statistically significant increase in the warfarin dose in the final week of the flucloxacillin treatment – ranging between 57% and 130%.

Awareness of this interaction should prompt close monitoring of the INR (International Normalised Ratio) in such patients in order to reduce the risk of anticoagulation treatment failure.

Internal Medicine Journal 2018; 48:860–863

Benefits and harms of screening men for abdominal aortic aneurysm in Sweden

Large reductions in the incidence of abdominal aortic aneurysm (AAA) and AAA—related mortality mean that results from randomised trials of screening for the disorder might be out—dated. The aim of this study was to estimate the effect of AAA screening in Sweden on disease-specific mortality.

The researchers compares data relevant to the incidence of AAA and related mortality in a cohort of men aged 65 years who had been screened with an age—matched cohort who had not been screened. They found that mortality decreased at similar rates in screened and non—screened subjects. There was a non—significant reduction in AAA mortality associated with screening.

AAA screening in Sweden did not contribute substantially to the large observed reductions in AAA mortality. The reductions were mostly caused by other factors, probably reduced smoking. The researchers noted that the prevalence of smoking in Sweden decreased from 44% in 1970 to 15% in 2010. They conclude that the small benefit and substantially less favourable benefit—to—harm balance call the continued justification of the intervention into question.

Lancet 2018; 391:2441–47

A randomized trial of early endovenous ablation in venous ulceration

Venous disease is the most common cause of leg ulceration. Although compression therapy improves venous ulcer healing, it does not treat the underlying causes of venous hypertension. Treatment of superficial venous reflux has been shown to reduce the rate of ulcer recurrence, but the effect of early endovenous ablation of superficial venous reflux on ulcer healing remains unclear.

To elucidate, this randomised trial enrolled 450 patients from 20 centres in the UK with venous leg ulcers. Half were treated with compression therapy and venous ablation of superficial veins within 2 weeks after randomisation. The other half had compression alone and were considered for endovenous ablation when the ulcer was healed or at six months if the ulcer had not healed.

Apparently early endovenous ablation of superficial venous reflex resulted in faster healing of venous leg ulcers and more time free from ulcers than deferred endovenous ablation.

N Engl J Med 2018; 378:2015–14