How to Check Formularies Before Prescribing: A Step-by-Step Guide for Providers

Every time you write a prescription, you're not just choosing a drug-you're also deciding if your patient can afford it. That's why checking the formulary before prescribing isn't optional-it's critical. A formulary (also known as a Preferred Drug List) is a list of medications covered by a health insurance plan. It's created by doctors and pharmacists to balance safety, effectiveness, and cost. Without checking it, you risk prescribing a drug your patient can't afford or that requires unexpected prior authorization. Let's cut through the confusion and learn exactly how to do this right.

What You're Actually Checking

Formularies aren't static documents. They're dynamic lists updated regularly. For example, HealthPartners publishes quarterly updates for Medicare plans in January, April, July, and October 2024. Medicare Part D plans must notify patients 60 days before changes. But here's the real issue: a single drug like Januvia can be Tier 3 in one plan, Tier 4 in another, or require step therapy. A Tiered Structure system breaks drugs into cost categories. Medicare Part D typically uses five tiers:

Each drug also has special flags: PA (Prior Authorization), ST (Step Therapy), or QL (Quantity Limit). For instance, Aetna's September 2024 documentation shows that Prior Authorization means your insurance requires approval before covering the drug. Step Therapy means you must try cheaper alternatives first. Quantity Limit restricts how much you can prescribe per month. These details change constantly-so checking isn't a one-time task.

How to Check Formularies in 5 Minutes

You don't need to be a pharmacy expert to do this. Here's exactly what to do:

1. Use the insurer's online tool. Most insurers like Aetna or UnitedHealthcare have search tools on their websites. For Aetna, you'll need the patient's county and plan name. A July 2024 MGMA survey found 74% of providers rated this tool "very helpful" for showing real-time PA requirements and tier costs.
2. Check your EHR's formulary checker. 67% of large hospital systems use embedded tools. Northwestern Medicine reported a 42% reduction in prescription abandonment after adding Epic's Formulary Check module in Q3 2023. If your system has this, it shows coverage details while you're writing the prescription.
3. Download the PDF formulary. Many insurers offer downloadable PDFs. HealthPartners publishes these quarterly. Always check the date-formularies change often. Rural practices still use these 41% of the time (per NRHA's September 2024 survey).
4. Call the insurer's provider hotline. 98% of Medicare Part D plans have 24/7 phone support. For urgent cases, Medicare requires responses within 24 hours for expedited requests. This works best for complex cases where online tools don't clarify coverage.

Why This Matters More Than Ever

A September 2023 Sermo survey of 1,247 clinicians found 68% spend 10-20 minutes per patient verifying coverage. Primary care doctors average 18.7 minutes per patient-more than specialists. Why? Because Tiered Structure rules vary wildly. For example, Januvia (a common diabetes drug) is Tier 3 in one Medicare plan, Tier 4 in another, and requires Step Therapy in a third. This isn't theoretical. A February 2024 American Medical Association report showed 88% of physicians experience care delays due to prior authorization issues. Worse, 34% of these delays caused serious adverse events for patients.

Current policy changes make this even more urgent. The Inflation Reduction Act introduces a $2,000 annual out-of-pocket cap for Medicare Part D starting in 2025. This is already reshaping formularies. Avalere's October 2024 analysis found 73% of 2025 Medicare formularies are moving more drugs to lower tiers to manage costs. Meanwhile, CMS requires all Medicare Part D plans to implement Real-Time Benefit Tools (RTBT) by January 1, 2026. These tools integrate coverage info directly into EHRs, cutting verification time significantly.

Common Mistakes to Avoid

Even experienced providers slip up. Here's what to watch for:

• Not checking the current version. Medicare Part D formularies are effective January 1 through December 31, 2024-but insurers can make mid-year changes with 60-day notice. Always verify you're looking at the latest update.
• Assuming all plans are the same. Commercial insurers like UnitedHealthcare use a four-tier structure, while Medicare uses five. Medicaid programs vary by state; 42 states have closed formularies requiring prior authorization for non-formulary drugs.
• Ignoring step therapy requirements. A 2023 JAMA Internal Medicine editorial noted 32% of cancer medication prior authorization requests face delays exceeding 48 hours. If a drug requires Step Therapy, you must document failed trials of cheaper alternatives first.
• Forgetting quantity limits. Some drugs like opioids have strict monthly limits. Prescribing 90 days' supply when the limit is 30 days will get your prescription denied.

How to Stay Ahead of Changes

Formularies evolve fast. Here's how to keep up:

• Bookmark insurer pages. For example, UnitedHealthcare's 2024 Commercial Drug List is at uhc.com/physicians/drug-list. Set calendar reminders for quarterly updates.
• Use CMS Plan Finder. This tool covers 99.8% of Medicare Part D plans and shows tier costs, PA requirements, and drug alternatives. It's updated daily.
• Ask patients about their plan. During intake, ask: "Do you know if your plan covers [drug name]?" Many patients can check their own formulary online through their insurer's portal.
• Track policy changes. The Inflation Reduction Act's $2,000 cap will force formulary redesigns through 2025. Watch for updates from CMS and organizations like IQVIA, which tracks $601 billion in U.S. prescription drug spending.