Your Patients Are Struggling to Find Phenytoin XR — Here's How You Can Help

If you've been fielding calls from frustrated patients who can't find their Phenytoin XR at the pharmacy, you're not alone. Intermittent supply disruptions continue to affect phenytoin extended-release capsules in 2026, and for patients on this narrow therapeutic index medication, even a short gap in supply can mean breakthrough seizures.

This guide provides a practical, step-by-step approach to helping your patients maintain access to Phenytoin XR — and what to do when the medication simply isn't available.

For the clinical and policy context behind these disruptions, see our provider shortage briefing.

Current Availability: What's the Picture?

As of February 2026, Phenytoin XR (extended-release capsules) is generally available from multiple generic manufacturers. However, the picture is uneven:

• Generic Phenytoin ER capsules (100 mg, 200 mg, 300 mg) are produced by several manufacturers but individual suppliers may experience production gaps
• Dilantin Kapseals (Viatris) and Phenytek brand products are available but at significantly higher cost ($80-$120+ vs. $18-$45 for generic)
• Phenytoin oral suspension has had formulations discontinued, increasing demand on the capsule supply
• Availability varies significantly by region, pharmacy chain, and wholesaler relationships

Why Are Patients Having Trouble Finding It?

Understanding the root causes helps you guide patients more effectively:

1. Declining prescribing volume means fewer manufacturers maintain active production lines for phenytoin, reducing supply redundancy
2. Narrow therapeutic index requirements create strict bioequivalence standards that limit new market entrants
3. Centralized ordering at chain pharmacies can't always respond to local demand fluctuations
4. Patients may be tied to a specific manufacturer's product, further limiting which pharmacies can fill their prescription
5. Discontinued formulations (oral suspension) have concentrated demand on extended-release capsules

5 Steps to Help Your Patients Get Their Phenytoin XR

Step 1: Direct Patients to Medfinder

Medfinder for Providers provides real-time pharmacy availability data, searchable by medication and zip code. You can:

• Check availability during the office visit and give the patient a specific pharmacy to try
• Share the Medfinder link with patients so they can search independently
• Bookmark it as a resource for your nursing staff to use when patients call about supply issues

This is often the fastest way to resolve the problem — many patients simply don't know which nearby pharmacies have stock.

Step 2: Write Flexible Prescriptions When Clinically Appropriate

For patients who can safely use any manufacturer's version of extended phenytoin sodium:

• Avoid writing "dispense as written" unless medically necessary
• Add a note allowing manufacturer substitution to give the pharmacy maximum sourcing flexibility
• Consider writing for a 90-day supply if insurance allows — this reduces refill frequency and the number of times the patient needs to find stock

For patients who clinically require a specific manufacturer's product (due to demonstrated sensitivity to formulation differences), document this in the chart and on the prescription, but acknowledge that this may limit availability.

Step 3: Recommend Independent Pharmacies

Independent pharmacies often maintain relationships with 3-5 drug wholesalers (vs. 1-2 for chain pharmacies). This gives them more options to source hard-to-find medications. Encourage patients to:

• Call local independent pharmacies directly
• Ask the independent pharmacy to special-order Phenytoin XR if it's not currently in stock
• Consider transferring their prescription to an independent pharmacy that can reliably source their medication

Step 4: Document a Backup Plan in the Chart

Proactively document an approved alternative medication in each phenytoin patient's chart. This way, if the patient calls after hours or over a weekend unable to find their medication, any covering provider can quickly authorize the backup.

Your documented backup plan should include:

• The specific alternative agent and dose
• Tapering/crossover instructions
• Blood level monitoring timeline
• When to follow up after the switch

Common alternatives to consider (see our alternatives guide for patient-facing information):

• Levetiracetam (Keppra): Fewest drug interactions, no TDM required, widely available, $10-$25/month generic
• Lamotrigine (Lamictal): Broad-spectrum, well-tolerated, but requires slow titration (weeks to reach therapeutic dose)
• Carbamazepine (Tegretol): Similar sodium channel mechanism, also NTI; not ideal as an emergency swap due to its own interaction profile
• Valproic Acid (Depakote): Broadest spectrum, but avoid in women of childbearing potential due to teratogenicity

Step 5: Counsel Patients on Early Refills

The simplest prevention strategy: advise patients to refill 7-10 days before they run out. Most insurance plans accommodate early refills for maintenance seizure medications. This buffer gives patients time to check multiple pharmacies if their usual one is out of stock.

Consider adding this as a standing instruction in your after-visit summary for all phenytoin patients.

Workflow Tips for Your Practice

Small changes in your workflow can significantly reduce patient frustration:

• Add a phenytoin availability flag to your EHR for affected patients, so any staff member who pulls up the chart is aware of potential supply issues
• Create a phone script for front desk or nursing staff to use when patients call about supply issues: direct them to Medfinder, suggest independent pharmacies, and offer to send the prescription to a different location
• Batch refill authorizations: When a patient reports difficulty finding Phenytoin XR, authorize refills at 2-3 different pharmacies so the patient can fill at whichever has stock
• Monitor ASHP/FDA shortage databases quarterly to stay ahead of supply changes
• Use telehealth for medication management follow-ups — this is particularly helpful for patients in rural areas where pharmacy options are limited

Alternatives: When Switching Makes Sense

Consider a planned transition off Phenytoin XR when:

• The patient has experienced recurrent supply disruptions (3+ over 6 months)
• The patient has phenytoin-specific side effects (gingival hyperplasia, hirsutism, coarsened facial features) that reduce quality of life
• The patient is a woman of childbearing potential (Phenytoin is Pregnancy Category D — risk of fetal hydantoin syndrome)
• The drug interaction burden is high (Phenytoin is a potent CYP3A4 inducer and is metabolized by CYP2C9/2C19)
• The patient would benefit from a medication that doesn't require therapeutic drug monitoring

When switching, remember:

• Never abruptly discontinue Phenytoin — taper over 1-2 weeks while titrating the new medication
• Recheck seizure frequency and new medication levels (if applicable) at 2 and 6 weeks
• Warn patients about potential temporary changes in seizure control during the transition

For drug interaction details to consider during transitions, see: Phenytoin XR Drug Interactions.

Final Thoughts

Phenytoin XR supply disruptions are manageable with proactive planning. The key interventions — directing patients to Medfinder, writing flexible prescriptions, recommending independent pharmacies, documenting backup plans, and counseling on early refills — take minimal time but can prevent medication gaps that lead to seizure emergencies.

For the patient perspective, share our patient guide to finding Phenytoin XR and our cost savings guide with your patients.

For provider-specific cost assistance tools, see: How to Help Patients Save Money on Phenytoin XR.