Last updated: March 2026
How Much Does Phenytoin (Dilantin) Cost?
Cost Breakdown by Type
| Type / Procedure | Without Insurance | With Insurance |
|---|---|---|
| 100mg Capsules Generic (30-day) | $10 – $30 | $0 – $10 |
| Extended-Release 100mg (30-day) | $10 – $40 | $0 – $12 |
| Brand Dilantin 100mg (30-day) | $30 – $60 | $5 – $15 |
| Oral Suspension 125mg/5mL | $15 – $50 | $0 – $15 |
What Affects the Cost
- Brand-name vs. generic availability
- Insurance formulary tier placement
- Pharmacy choice (retail vs. mail-order vs. Costco)
- Manufacturer savings cards and coupons
- Dosage and quantity prescribed
- Geographic location
Insurance Coverage
Typical coverage: Covered as Tier 1 generic; brand Dilantin may require prior auth
Most insurance plans use a tiered formulary: Tier 1 (generic) $0-$15 copay, Tier 2 (preferred brand) $25-$75, Tier 3 (non-preferred brand) $50-$150, Tier 4 (specialty) $100-$500+. Prior authorization may be required for certain medications. Step therapy may require trying cheaper alternatives first.
How to Save Money
- Always ask for generic when available — saves 50-90%
- Use GoodRx, RxSaver, or similar discount cards
- Costco pharmacy is open to non-members and often has lowest prices
- Mark Cuban's Cost Plus Drugs offers transparent low pricing
- Manufacturer patient assistance programs provide free medication to qualifying patients
- HSA/FSA funds can cover medication costs tax-free
Related Procedures & Costs
Frequently Asked Questions
Phenytoin has a narrow therapeutic index. Small differences between generic manufacturers may affect blood levels. Some neurologists prefer consistent brand use.
Generic phenytoin costs $10 to $40/month. Brand Dilantin costs $30 to $60/month.
Yes, phenytoin blood levels, CBC, and liver function should be checked regularly. Levels must stay in a narrow therapeutic range.