Key result
The dramatic warfarin-erythromycin interactions reported previously may be confounded by other drugs, as some patients show only modest prothrombin time elevations (e.g., 23.2 to 31.3 seconds).
Why the study?
Does erythromycin interact with warfarin to increase prothrombin time?
Does erythromycin interact with warfarin to increase prothrombin time?
Answers are grounded in this paper and cite their sources.
This letter highlights the need to consider confounding medications when evaluating the clinical significance of the warfarin-erythromycin interaction.
To the Editor. —The recent article by Sato et al1in the December 1984Archivesprovided important data about a clinically significant interaction between warfarin and erythromycin, but we believe their discussion was incomplete. Just as their patient exhibited several factors that may have increased his sensitivity to warfarin, the two case reports they cited involved confounding variables. The patient reported by Bartle2and the individual described by Schwartz et al3were receiving quinidine and ticrynafen, respectively. Each of these agents has been reported to potentiate the effects of oral anticoagulants.4-6In contrast to these reports of dramatic interactions, Husserl7described a patient in whom only a modest elevation in the prothrombin time (PT) from previous values of 18 to 23.2 s to 31.3 s occurred after erythromycin was administered. This relatively modest increase is more consistent with the findings of Schwartz et al,8
No takes yet. Share an insight, caveat, or question.
Henry I. Bussey (1985) conducted a letter in Warfarin-erythromycin interaction. Erythromycin was evaluated on Prothrombin time (PT). The dramatic warfarin-erythromycin interactions reported previously may be confounded by other drugs, as some patients show only modest prothrombin time elevations (e.g., 23.2 to 31.3 seconds).
Synapse has enriched 10 related papers. Consider them for comparative context: