Switching Toprol XL to Lopressor

[mayormike]

My medication was recently switched from Toprol XL to Lopressor due to unavailability through the mail order company mandated by my prescription insurance. I previously took 300mg each morning of the Toprol XL, and now am taking 300mg of Lopressor in the morning. After years of being well regulated, I am now experiencing tachycardia, arrthymias, shortness of breath, and palpitations. I feel as though my medication is not the correct dose and/or that I need additional medication. The only instructions I received were to take the same as before and that there was no difference between the two medications; however my research says the duration for the medications is different.  In order to be prepared to question my doctor appropriately, should I just ask to divide the dose, and if so,how should it be divided, and is the conversion in dosage equal or do I need a higher dose?  If it were possible, I would prefer to have my Toprol XL back.

[PharmDlamar]

The correct coversion of toprol xl 300 mg = lopressor 150 bid for a total of 300 daily. It should have not been 300 mg qd at once as this should have been giving in divided doses. Hope this helps!