HCPCS code S0177: Levamisole 50 mg billing, coverage and fee schedule

Key takeaways

HCPCS code S0177 describes levamisole hydrochloride, oral, 50 mg, an anthelmintic with immunomodulatory activity. One unit of service is one 50 mg oral dose.

S0177 is an HCPCS Level II S-code approved by the HCPCS National Panel. Traditional Medicare fee-for-service does not cover it, so Medicaid and commercial payers are its only realistic users.

The JW and JZ drug-waste modifiers do not apply to S0177, because CMS wrote that policy for single-dose vials and single-use packages of injectable drugs.

Ergamisol, the US human brand of levamisole, was withdrawn in 2000. A current S0177 claim usually turns out to be a mis-keyed S0176 or S0178.

Practice management software like Pabau helps specialty practices track units of service and reduce denials on HCPCS drug codes.

HCPCS code S0177 is an HCPCS Level II billing code with the official descriptor Levamisole hydrochloride, oral, 50 mg. It sits in the S-series (S0100 to S9999), the temporary codes used by Medicaid programs and commercial payers. One unit of service is one 50 mg oral dose.

S-codes are approved by the HCPCS National Panel rather than by one agency alone. The panel brings together the Centers for Medicare and Medicaid Services (CMS), the Blue Cross Blue Shield Association, and America’s Health Insurance Plans (AHIP). It adds or changes a code only by unanimous consent.

Ergamisol, the levamisole brand approved for human use in the United States, was withdrawn in 2000. The code still appears in HCPCS references, so a US claim carrying it today usually points to a coding error rather than a dispense.

What drug does S0177 represent?

Levamisole hydrochloride is an oral anthelmintic that also acts as an immunomodulator. Against parasites, it overstimulates nicotinic receptors in nematode muscle and paralyzes the worm. In people, researchers found that it restored depressed T-cell function, which is what drew oncologists to it.

The FDA approved levamisole in 1990 as an adjuvant to fluorouracil (5-FU) after surgical resection of Dukes’ stage C colon cancer. That pairing anchored adjuvant colon cancer therapy for much of the 1990s. Later regimens replaced levamisole with leucovorin, and the US brand was withdrawn in 2000 after reports of agranulocytosis.

Levamisole is still prescribed outside the United States and still used in veterinary medicine. No human product is marketed here, so S0177 describes a drug your practice is very unlikely to supply.

The HCPCS Level II system gives named oral drugs their own codes, like S0177. The alternative is a miscellaneous code such as J8499 or J8999. A dedicated code makes claim submission cleaner, because the payer knows which drug and strength was supplied without extra documentation.

• Drug class: Anthelmintic (imidazothiazole) with immunomodulatory activity
• Mechanism: Nicotinic receptor agonism in parasites, plus restoration of T-cell function in humans
• Historical clinical context: Adjuvant colon cancer therapy alongside 5-FU, plus treatment of worm infections
• Route: Oral tablet, not injection or infusion
• Billing unit: Per 50 mg supplied
• US market status: Ergamisol withdrawn in 2000, with no human product marketed today

Important: HCPCS code S0177 describes the drug for billing purposes only. This article does not constitute clinical guidance on levamisole dosing or patient selection. Always follow current clinical protocols and consult prescribing references for treatment decisions.

HCPCS Level II S-codes: Where S0177 fits

The HCPCS Level II coding system is divided into code series identified by a leading letter. The S-series covers temporary codes for drugs, supplies, and services that CPT codes do not capture. These items also have no permanent HCPCS code in another series.

Key characteristics of S-codes:

• Approved by the HCPCS National Panel: CMS, the Blue Cross Blue Shield Association, and AHIP must all agree before a code changes
• Updated on a quarterly cycle: codes can be added, revised, or deleted between updates, so verify current status before billing
• Not recognized by traditional Medicare fee-for-service: submitting an S-code on a Medicare FFS claim will result in rejection or denial
• Used primarily by Medicaid and commercial payers, each of which may independently decide whether to cover a given S-code

Within the S0100 to S0199 range, the oral drug codes run in alphabetical order by drug name. S0177 sits between S0176 (hydroxyurea, oral, 500 mg) and S0178 (lomustine, oral, 10 mg). Every code in that run describes a tablet or capsule the practice supplies.

The T-series works the same way for state Medicaid agencies. A code such as T2019 is billable to Medicaid but never to Medicare fee-for-service.

Medicare coverage for HCPCS code S0177

Traditional Medicare fee-for-service does not cover HCPCS code S0177 or any other S-code. CMS policy excludes S-codes from Medicare FFS reimbursement. Submitting S0177 on a CMS-1500 claim for a Medicare FFS beneficiary will result in claim denial.

A second exclusion sits behind the first. Part B does not pay for most self-administered oral drugs. It carves out a narrow exception for oral anticancer drugs that share an active ingredient with an injectable form. Levamisole never had a human injectable form here, so that exception does not reach it.

Medicare Advantage (Part C) plans are a separate question. Private insurers run them and set their own formularies and coverage policies. Oral drugs usually route to the plan’s pharmacy benefit rather than a medical claim, so verify before assuming S0177 is billable.

Medicaid and commercial payer billing for S0177

Medicaid is the primary government payer that uses HCPCS S-codes, and coverage is not uniform. Each state Medicaid program sets its own fee schedule and coverage policies. A code covered in one state may be excluded in another, so check the state agency’s published fee schedule before billing.

Oral drugs raise a routing question that injectables do not. Most oral prescriptions reach the payer as a pharmacy claim carrying a National Drug Code (NDC).

An S-code like S0177 belongs on a medical claim, and only when the practice itself supplied the tablets. Send it down the wrong benefit and the claim denies as non-covered or duplicate.

Prior authorization is common for drugs billed under HCPCS Level II codes. Medicaid managed care plans and commercial payers frequently require an authorization number on the claim before they will process it. Submitting without an approved authorization is a leading denial reason on specialty drug codes.

Dispensing records fall under HIPAA documentation rules whatever the payer. Keeping them complete is a compliance obligation as much as a billing one, and it protects the practice during an audit.

S0177 fee schedule and reimbursement rates

Because S0177 is an S-code excluded from Medicare FFS, CMS publishes no national physician fee schedule rate for it. Drug codes Medicare does recognize, such as J1950, carry a published payment limit. S0177 has none, so reimbursement depends entirely on the payer’s own fee schedule.

State Medicaid programs that list the code express the rate per 50 mg unit of service. Commercial payers negotiate rates individually or set them against average wholesale price (AWP) benchmarks.

Levamisole’s market status complicates that last point. With no human product marketed in the United States, there is no current AWP to price against. Any figure you find in an older pricing file is decades out of date and should not be quoted to a patient.

• Medicare FFS rate: None, because the code is not recognized
• Medicaid rate: State-specific, so check your state’s drug fee schedule
• Commercial rate: Negotiated or AWP-based, so confirm with the payer contract or remittance history
• Unit of service: Rate applies per 50 mg supplied

Cross-check the descriptor and current status against the CMS quarterly HCPCS update before you bill. Never state a dollar figure as a definitive reimbursement amount without confirming it against the current payer fee schedule.

How to bill HCPCS code S0177: Claim form, units, and documentation

Billing HCPCS code S0177 correctly requires attention to claim form placement, units, NDC reporting, and documentation. Each of these elements must align for the claim to process cleanly. Practices using claims management software can configure drug code rules to flag missing data before submission.

1. Claim form placement: Report S0177 in Box 24D of the CMS-1500 form. Each date of service requires its own line.
2. Units of service: Enter the total number of 50 mg units supplied. Three 50 mg tablets supplied on one date is 3 units.
3. NDC reporting: Many state Medicaid programs require the 11-digit NDC and the dispensed quantity in the shaded area of Box 24.
4. Diagnosis code: Link an ICD-10-CM code that supports medical necessity. Historically that meant the resected colon cancer. For anthelmintic use it is the documented parasitic infection.
5. Prior authorization: If required by the payer, enter the authorization number in Box 23 of the CMS-1500.
6. Documentation: Retain the prescription and dispensing record showing date, drug name, strength, quantity supplied, and prescriber. For an oral drug, that record is the audit trail.

Which modifiers apply to S0177

Modifier expectations for S0177 differ from the injectable drug codes coders often work alongside. The JW and JZ drug-waste pair does not apply here. CMS wrote that policy for amounts discarded from single-dose vials and single-use packages. That matters to an IV therapy practice, but a tablet has no vial to discard.

That leaves payer-specific modifiers. Check the plan’s published policy before appending any of them, because S-code rules vary widely from one payer to the next.

The AAPC HCPCS code lookup lists coding tips and payer notes that help confirm modifier requirements payer by payer.

Your medical forms have to capture strength, quantity, and date at the point of dispensing. Without that, you cannot defend the units on the claim.

Related HCPCS codes to S0177

The S0175 to S0179 block is an alphabetical run of oral drug codes. Knowing the neighbors prevents miscoding when a practice supplies tablets from more than one of them. The table below covers the codes immediately surrounding HCPCS code S0177.

Every code in this run is oral, so the route recorded in the chart will not tell you which one to pick. Confirm the drug name and strength against the dispensing record each time.

Injectable drugs sit in the J-series instead, where a code such as J0881 carries its own unit and waste rules. A short cheat sheet of the drugs you supply removes most of these errors.

How practice management software simplifies HCPCS drug billing

Practices that supply drugs in-house hit the same workflow problem, from oncology groups to functional medicine practices. One drug may be billed at different rates, with different data requirements, to different payers. Managing those rules by hand in a spreadsheet invites errors.

Practice management software like Pabau centralizes those rules and enforces them when the claim is generated. Capabilities that cut S-code billing errors include:

• Pre-configured code rules: Set unit-of-service defaults for specific drug codes, so billing staff enter units accurately every time
• Payer rule prompts: Flag drug claims missing an NDC, a unit count, or a required authorization number before they go out
• Payer-specific routing: Route claims to the correct payer workflow automatically, so non-covered S-codes never reach Medicare FFS
• Documentation integration: Link dispensing records to claims, so the audit trail is attached from the start instead of reconstructed after a denial

Digital intake forms feed straight into the billing workflow. Drug name, strength, and date captured at the point of care then match what goes out on the claim. EHR integration keeps clinical and billing data in sync rather than re-entered by hand.

Oncology charts carry sensitive diagnosis and treatment detail, so patient data security tools matter as much as billing accuracy.

Tired of manual HCPCS claim errors?

Pabau’s claims management lets specialty practices configure drug code rules, track units of service, and catch missing claim data before anything goes out. See how it works in a live demo.

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Conclusion

Treat an S0177 line as a question before you treat it as a claim. The code is valid, but the drug behind it has not been available in the US for more than two decades.

If the dispensing record confirms levamisole, the billing work is straightforward. Get the units right at one per 50 mg, and add the NDC where the state requires it. Then confirm the payer covers S-codes at all.

If it does not, the cleaner path is often a pharmacy claim rather than a medical one. That choice costs nothing to make up front and saves a rework cycle later.

Managing these rules across multiple payers is easier with practice management software built for specialty billing. Book a demo to see how Pabau handles HCPCS Level II drug code workflows end to end.

Continue your research

Billing an injectable drug instead of a tablet? J2010 walks through units, NDC reporting, and the payer rules that apply to a J-series drug code.

Need a second worked example of drug units? J2320 shows how dosage maps to billable units when one vial covers several doses.

Billing a controlled drug in the office? J2175 covers documentation and unit reporting for an injectable analgesic supplied on site.

Working with other temporary HCPCS codes? G0162 explains how the G-series handles services that have no permanent code yet.

Billing supplies rather than drugs? A4490 sets out how the A-series supply codes are documented and submitted.

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