Metoprolol succinate and metoprolol tartrate are different salts of the active ingredient metoprolol. Tartarate salt is the immediate release formulation and succinate salt is the extended release formulation. The difference is that extended release formulation is usually given once a day and immediate release formulation in divided doses and also the dose titration varies for both. I would have suggested my patient an alternative called atenolol. Atenolol also belongs to same class but can have less side effects of central nervous system like confusion and memory loss. Feel free to discuss the above points with your consultant. Hope this solves your concerns. Thank you.