Complex sentence: Metoprolol, marketed under the tradename Lopressor and/or Toprol based on what salt form it is in (Tartrate vs. Succinate), is a selective β 1 receptor blocker medication.
Split into simpler sentences: Metoprolol, marketed under the tradename Lopressor and/or Toprol based on what salt form it is in (Tartrate vs. Succinate). It is a selective β 1 receptor blocker medication.