Prescription Costs & Part D
What is the difference between a preferred and standard pharmacy?
Last reviewed: · Big Sioux Benefits Data Desk
Both are in your plan's network and both will fill your prescription, but a preferred pharmacy has agreed to lower cost sharing with your plan, so the identical drug on the identical day can cost you less there than at a standard network pharmacy. A third category, out-of-network, may not be covered at all except in limited circumstances.
The qualifier: preferred status is a contract between the pharmacy and your specific plan, so it varies plan by plan and can change from year to year. The pharmacy down the street may be preferred under one plan and standard under another, and the pharmacy that was preferred for you in 2025 is not guaranteed to be in 2026. This matters more in rural South Dakota than in Sioux Falls, because a plan with a narrow preferred network may not have a preferred pharmacy within a reasonable drive of a smaller community.
The three categories
| Pharmacy type | Covered? | Your cost |
|---|---|---|
| Preferred network | Yes | The plan's lowest cost sharing |
| Standard network | Yes | Higher than preferred for the same drug |
| Out of network | Usually not, except in limited situations | Potentially the full price, which may not count toward your cap |
| Mail order | Usually, often at preferred pricing | Frequently the lowest for 90-day supplies |
Two things worth doing once a year. Check that your regular pharmacy is still preferred under your plan for the coming year, because that status is a plan decision that can change quietly at renewal. And compare a 90-day mail-order fill against three 30-day retail fills for any maintenance drug you take, since the gap is often larger than people expect. When you are comparing plans, the pharmacy question belongs alongside the tier question, not after it.
Sources
- Medicare.gov — Costs for Medicare drug coverage — accessed 2026-08-21
- Medicare.gov — What Medicare Part D drug plans cover — accessed 2026-08-21
- CMS — CY2026 Medicare Advantage and Part D Landscape Source Files — plan year 2026; accessed 2026-08-21
Related questions
Can I use any pharmacy I want with Medicare Part D?
You can fill anywhere that will serve you, but what your plan pays depends on network status. Preferred and standard network pharmacies are covered at different cost-sharing levels, while out-of-network fills are usually not covered outside limited situations such as an emergency away from home, and may not count toward your out-of-pocket cap.
Is mail order always cheaper?
Not always, but often for maintenance drugs taken every month, especially at a 90-day supply. It is worth pricing your specific drugs both ways rather than assuming. Mail order is generally a poor fit for a drug you have just started, since a 90-day supply of something you may stop taking is money at risk.
Drug costs turn on your specific prescriptions, so the arithmetic is worth doing once, properly: book a free, no-pressure conversation, see your county's South Dakota plan lineup, or browse all answers. SHIINE, the state's free counseling program, is at 1-800-536-8197 and sells nothing.
Big Sioux Benefits is a licensed insurance agency, not affiliated with or endorsed by the U.S. government or the federal Medicare program. We do not offer every plan available in your area. Contact Medicare.gov, 1-800-MEDICARE, or SHIINE (South Dakota's SHIP) for all of your options.