‘Have you had Viagra within the past 24 hours?’


Rapid drug-induced vasodilation is essential in treating coronary medical emergencies. Through oral or sublingual administration of glyceryl trinitrate (GTN), changes occur in cyclic guanosine monophosphate (cGMP) levels, as well as a reduction in blood pressure. Patients who require GTN treatment may also take vasodilatory medication for other medical conditions, including erectile dysfunction (ED). Current guidance in the UK contraindicates GTN use alongside sildenafil (commercially known as Viagra) and other related drugs, owing to the likelihood of life-threatening hypotension. Therefore, it is essential that paramedics and emergency responders establish whether patients have taken sildenafil within the past 24 hours before administering GTN. This article identifies the action mechanisms of both drugs, and provides an evidence-based explanation for co-administration outcomes; a dramatic drop in blood pressure which can potentially be fatal. This article also reflects on the challenges faced by paramedics when considering administration of GTN to determine whether sildenafil has been taken within the past 24 hours.

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