Your Patients Are Struggling to Fill Phentermine — Here's How You Can Help

You prescribe Phentermine. Your patient leaves the office optimistic and motivated. Two hours later, they call back: their pharmacy doesn't have it. This scenario is playing out in clinics across the country, and it's more than an inconvenience — it disrupts treatment plans and erodes patient confidence.

As a provider, you're not responsible for pharmacy inventory. But there are concrete steps you can take to minimize fill failures and keep your patients on track. This guide covers what's happening with Phentermine availability and what your practice can do about it.

Current Availability: What You Need to Know

Phentermine is not in an official FDA shortage as of 2026, but pharmacy-level stock-outs remain common. The situation is driven by:

• High demand: Weight-loss medication prescriptions have surged across the board. Phentermine, as the most affordable option, has seen significant increases in utilization.
• DEA quotas: Schedule IV manufacturing limits cap annual production, and demand has outpaced quota adjustments in recent years.
• Uneven distribution: Distributors allocate based on historical ordering. Pharmacies with historically low Phentermine volume may receive limited supply even when demand increases locally.
• Chain pharmacy limitations: Large chains use centralized ordering algorithms that can be slow to react to local demand changes.

For a deeper dive into the supply situation, see our provider shortage briefing.

Why Patients Can't Find Phentermine

Understanding the patient experience helps providers troubleshoot more effectively:

• Single pharmacy reliance: Most patients try only their regular pharmacy. If it's out of stock, they assume it's unavailable everywhere.
• Paper prescriptions: Patients with paper prescriptions can only try one pharmacy at a time, which slows the process significantly.
• Formulation specificity: A prescription written for "Phentermine 37.5 mg tablets #30" can only be filled with that exact product. If the pharmacy has 15 mg capsules but not 37.5 mg tablets, they can't substitute without a new prescription.
• Timing: Patients who wait until they're out of medication face more pressure and fewer options.

What Providers Can Do: 5 Practical Steps

Step 1: Default to E-Prescribing

Electronic prescriptions give patients the flexibility to choose which pharmacy to send their prescription to — or to have it transferred if the first pharmacy is out of stock. Paper prescriptions for controlled substances limit patients to a single pharmacy attempt.

If your state allows e-prescribing for Schedule IV medications (most do, and many now mandate it), make it your default for Phentermine.

Step 2: Prescribe With Availability in Mind

The 37.5 mg tablet is the most commonly prescribed strength and the most frequently out of stock. Consider these alternatives:

• Phentermine 15 mg capsules: Often more available; two capsules provide 30 mg (not equivalent to 37.5 mg, but effective for many patients)
• Phentermine 30 mg capsules: Another option with potentially better availability
• Lomaira 8 mg ODT: Taken three times daily before meals; provides 24 mg total daily dose; frequently in stock
• Adipex-P brand: Costs more but may be in stock when generics aren't

Discuss alternative dosing with patients upfront so they're not surprised if you need to adjust their prescription.

Step 3: Direct Patients to Medfinder

Medfinder provides real-time pharmacy stock data for Phentermine and other medications. You can:

• Recommend patients check Medfinder before going to the pharmacy
• Have your front desk or care coordination team check availability and identify stocked pharmacies
• Bookmark Medfinder on office computers for quick staff access

This single step can dramatically reduce call-backs from patients who can't fill their prescriptions.

Step 4: Build Relationships With Independent Pharmacies

Independent pharmacies often have advantages over chains when it comes to controlled substance availability:

• They work with multiple distributors and can source from whoever has stock
• They can prioritize specific medications based on local prescribing patterns
• They typically have more flexibility in ordering quantities
• They may be willing to hold or reserve stock for your patients if you establish a referral relationship

Identify 2-3 independent pharmacies near your practice and establish communication with their pharmacists.

Step 5: Set Patient Expectations and Plan Ahead

A brief conversation at the time of prescribing can prevent many fill issues:

• "Phentermine can sometimes be hard to find. If your pharmacy is out of stock, check Medfinder or try an independent pharmacy."
• "Don't wait until you're out of medication to try filling your refill — start 5-7 days early."
• "Call our office if you can't find it. We can help you locate a pharmacy or adjust the prescription."

This takes 30 seconds and saves significant time in follow-up calls and messages.

When to Consider Alternatives

If a patient consistently can't find Phentermine, or if they've completed a 12-week course and need continued pharmacotherapy, consider transitioning to:

• Qsymia (phentermine/topiramate ER): Contains phentermine at lower doses; approved for long-term use; available through REMS-certified pharmacies
• Contrave (naltrexone/bupropion): Non-controlled; good for patients with cravings or emotional eating patterns
• GLP-1 receptor agonists: Wegovy (semaglutide) or Zepbound (tirzepatide) for patients who need more significant weight loss and have insurance coverage or financial means
• Orlistat: Non-stimulant option; available OTC as Alli

For a detailed comparison, share our alternatives to Phentermine guide with patients.

Workflow Tips for Your Practice

Here are quick workflow adjustments to reduce Phentermine fill failures:

• Add a note to your Phentermine template: "Check Medfinder.com for pharmacy availability before sending to pharmacy"
• Train MAs and front desk staff: They can check Medfinder and help patients identify stocked pharmacies before the patient leaves the office
• Create a quick-reference list: Keep a list of 3-5 pharmacies that reliably stock Phentermine in your area, including at least 2 independents
• Use your EHR favorites: Set up alternative Phentermine formulations as quick-order favorites so switching strengths is seamless
• Follow up proactively: For new Phentermine starts, consider a 48-hour follow-up message asking if they were able to fill the prescription

Final Thoughts

Phentermine availability challenges aren't going away immediately, but they're manageable with the right approach. By e-prescribing, diversifying formulations, leveraging tools like Medfinder, and setting clear patient expectations, you can minimize treatment disruptions and keep your patients moving toward their goals.

The bottom line: a few small workflow changes in your practice can make a significant difference in your patients' experience filling Phentermine.

Related reading:

• Phentermine Shortage: What Providers Need to Know in 2026
• How to Help Patients Save Money on Phentermine
• Phentermine Drug Interactions: What to Avoid