No. J1165 is a HCPCS Level II code, maintained by CMS, that identifies the drug supplied. CPT codes are five-digit numbers from the AMA that describe services. Giving the drug, for example an injection or infusion, is usually reported with a separate CPT administration code.

What NDCs are billed under J1165?

CMS's ASP crosswalk for October 1, 2026 through December 31, 2026 lists 9 NDCs under J1165, for Phenytoin Sodium. The table on this page shows each one with its billing units per package.

What is the Medicare payment limit for J1165?

$0.513 per 50 mg, effective October 1, 2026 through December 31, 2026, from CMS's Part B drug payment limit file. Multiply by the units billed for the allowed amount before deductible and coinsurance. It is not a coverage decision.

What is one billing unit of J1165?

One unit of J1165 is 50 mg, as stated in the code's descriptor. Units to report = dose given ÷ 50 mg.

J1165 J-Code: Phenytoin sodium — Billing Units & NDCs

In short

J1165 is the HCPCS Level II code for injection, phenytoin sodium, per 50 mg. CMS assigns NDCs for Phenytoin Sodium to it. One billing unit is 50 mg. The Medicare Part B payment limit is $0.513 per unit (October 1, 2026 through December 31, 2026).

Code

CMS HCPCS file

HCPCS codeJ1165

Billing unit50 mg

Descriptor: Injection, phenytoin sodium, per 50 mg
Short descriptor: Phenytoin sodium injection
Code set: HCPCS Level II, maintained by CMS
Effective: Jan 1, 1997

The billing unit is read from the descriptor. Confirm it against the CMS file before billing.

Medicare Part B payment limit

CMS ASP file

Payment limit per unit$0.513

Per50 mg

Coinsurance20%

Effective October 1, 2026 through December 31, 2026. Payment allowance limits subject to the ASP methodology are based on 2Q26 ASP data. A payment limit is not a coverage decision; the Medicare contractor decides coverage. CMS ASP pricing files

Units and claim line

Units = dose given ÷ 50 mg. For example, 5000 mg is 100 units. Enter the dose to get the units and the NDC line for the CMS-1500 and the 837P.

Dose given (mg)

HCPCS units (1 unit = 50 mg)

Modifier

NDC (11-digit)

NDC unit qualifier

NDC quantity

Enter the dose given to build the claim line.

NDCs billed under J1165

CMS’s ASP NDC–HCPCS crosswalk (effective October 1, 2026 through December 31, 2026) assigns 9 NDCs to J1165 for Phenytoin Sodium. Billing units per package are CMS’s figures for this code’s unit.

NDCs assigned to J1165 in the CMS ASP crosswalk
Drug	NDC (11-digit)	Labeler	Package	Billing units per package
Phenytoin Sodium	00404-9808-05	Henry Schein Inc.	5	5
Phenytoin Sodium	00404-9932-02	Henry Schein Inc.	2	2
Phenytoin Sodium	00404-9933-05	Henry Schein Inc.	5	5
Phenytoin Sodium	00641-0493-25	Hikma Pharmaceuticals USA Inc.	25 × 2	50
Phenytoin Sodium	00641-2555-10	Hikma Pharmaceuticals USA Inc.	10 × 5	50
Phenytoin Sodium	00641-6138-25	Hikma Pharmaceuticals USA Inc.	25 × 2	50
Phenytoin Sodium	00641-6139-10	Hikma Pharmaceuticals USA Inc.	10 × 5	50
Phenytoin Sodium	51662-1251-01	HF Acquisition Co. LLC, DBA HealthFirst	2	2
Phenytoin Sodium	51662-1251-03	HF Acquisition Co. LLC, DBA HealthFirst	25 × 2	50

J1165: common questions

Is J1165 a CPT code?: No. J1165 is a HCPCS Level II code, maintained by CMS, that identifies the drug supplied. CPT codes are five-digit numbers from the AMA that describe services. Giving the drug, for example an injection or infusion, is usually reported with a separate CPT administration code. CPT codes for drug administration.
What NDCs are billed under J1165?: CMS's ASP crosswalk for October 1, 2026 through December 31, 2026 lists 9 NDCs under J1165, for Phenytoin Sodium. The table on this page shows each one with its billing units per package.
What is the Medicare payment limit for J1165?: $0.513 per 50 mg, effective October 1, 2026 through December 31, 2026, from CMS's Part B drug payment limit file. Multiply by the units billed for the allowed amount before deductible and coinsurance. It is not a coverage decision.
What is one billing unit of J1165?: One unit of J1165 is 50 mg, as stated in the code's descriptor. Units to report = dose given ÷ 50 mg. J-code billing units.

J1165 — Injection, phenytoin sodium, per 50 mg