Keep in mind that when you switched from Toprolol ER (Metoprolol
Succinate) to Lopressor (Metoprolol
Tartrate), you lost the timed released advantage. If you were taking 25mg. pills of
each medication, you are loosing a great deal of
the latter drug's effectiveness as the day wears on. The half life of
Metoprolol Tartrate is only 3-7 hours. So you must take it at least twice a day for
it to be effective the entire 24 hour period. Also 25mg., once a day is a a very small dose.