When you get a script filled for vitamin d from pharmacy what exactly is in it? Besides vitamin d, are there fillers, soy, other inert ingredients?

Yes-excipients. The Vitamin D tablet has only milligrams of Vitamin D, but the tablet weighs much more (a few grams I bet). Most tablets (not just Vitamin D) have excipients - fillers, coloring agents, gelatin (for the outer capsule). Each maker has their own proprietary "formula" for the excipients, so no two Vitamin D tablets will be exactly alike. In all cases, the FDA regulates what's used. They shd be safe4u.
Some. I checked 2 brands of 50,000 unit Decara and Dailyvite. Decara contains yellow dye and soybean oil. Dailyvite didn't mention any ingredients other than D3. Some of the lower doses state they are gluten, soy and lactose free. If that's important to you, ask the pharmacist for a list of inert ingredients. Thanks for trusting HealthTap!
Depends on brand... Most prescription vitamin D supplements contain vitamin D3, from animal sources. Most also need some "inactive" ingredients to hold them together: gelatin, glycerin, lecithin, etc. You can look up your exact brand on drugs.com or rxlist.com and read all of the ingredients.
Ask your pharmacist. Different Vit D preparations have differing inert ingredients your Pharmacist will be glad to tell you what is in the medication he/she uses to fill the Prescription. Hope this helps Dr Z.
There are others. No medication is completely made of the active ingredient, in fact, most contain very little and much of any pills is made up of fillers/delivery mechanisms that allow for improved convenience/dosing. What those are depends on the manufacturer of your respective pill.
With script, pure(?) If you fill a prescription for vitamin D (usually it would be vitamin D3) it should be pure vitamin D without fillers, etc. That is what the FDA monitors -- strength, purity, safety --for prescription drugs. Supplements are not subject to FDA monitoring; consequently, their purity can not be guaranteed. Each manufacturer might include different fillers, colors, inert ingredients--read label.