Evidence Based or Mechanism Based Therapeutics

摘要

I recently had the experience of having to justify the use of verapamil to treat a patient instead of beta blocker. The patient had ischemic heart disease with a vasospastic component, as well as a history of very mild asthma suspected on the basis of wheezing when exposed to cat dander. The rationale for prescribing the verapamil is that patients with vasospasm need coronary dilation and a beta blocker reduces coronary dilation by blocking sympathetic vasodilatory neural innovation while leaving alpha constrictor innovation unopposed. The beta blocker can worsen bronco constriction. However, there is a large body of evidence that beta blockers reduce mortality in patients with ischemic heart disease and little evidence that verapamil reduces mortality. The advocate of prescribing a beta blocker felt that evidence based medicine would clearly support the beta blocker as the only acceptable therapy.