I'm in toprol (metoprolol) xr, synthroid, vitamin d and miralax daily. are their any interactions between these?

Not realy: Orthostatic hypotension, limb discomfort, dysarthria. In about 3 people from a group of 80 patients study especially female above the age of 50 years old. Good luck.

A valuable resource: You can use a drug interaction checker whenever you have questions about drug-drug interactions or drug - food interactions. Here is one option (Drugs.Com): https://www.drugs.com/drug_interactions.php Your pharmacist is also an excellent source of information.