Professor Peter Weissberg, Medical Director of the British Heart Foundation said, "However, the increased risk is small, and many patients with chronic debilitating pain may well feel that this small risk is worth taking to relieve their symptoms".
Rezultati raziskav so mešani, metaanaliza dokumentov in poročil do aprila 2006 kaže relativno večjo stopnjo bolezni srca (1,63 v primerjavi z neuporabniki).