The best "medicine" is the one that works for you! Fortunately there are a finite number you can try, but that does carry some risk, as it can work on the SVT but also create other disturbances of the heart's electrical system. As an alternative to drug therapy, there is also a procedure referred to as cardiac ablation which destroys the source of the SVT and makes drug therapy unnecessary. Many of us here have had this done, usually after drugs have failed (which they often do in SVT cases). You need to work with your physician to determine which path is best for you.
Discuss these with your physician....no single answer since it depends on each diagnosis.