Opioid Treatment Program Billing in 2026: Medicare's Weekly Bundle Rules

How the G2067-G2080 Bundled Codes Work, Where Take-Home Medication Billing Goes Wrong, and the $178 Million OIG Already Found

By Team Rcmaxis  ·  November 1, 2026  ·  12 min read

The HHS Office of Inspector General found that Medicare made roughly $178 million in potentially improper payments to opioid treatment programs for opioid use disorder services, in a single audit (report A-09-22-03005). A separate OIG review went further, estimating Medicare could have saved about $301.5 million if OTP bundled payment rates had actually matched the services enrollees received instead of a flat weekly rate regardless of what was delivered. Neither number is a projection. Both came from real claims OIG pulled and tested, and both point at the same structural issue: Medicare pays OTPs through drug-specific weekly bundles, and bundles are exactly the kind of payment structure that hides billing errors until someone goes looking.

If your program bills Medicare for opioid use disorder treatment, this is the part of OTP billing that actually determines whether you keep what you're paid: the weekly bundle codes, the add-ons that ride alongside them, and the narrow rules around take-home medication that generate most of the improper-payment findings OIG has already published.

How the Weekly Bundle Actually Works

Medicare pays OTPs through drug-specific HCPCS codes, each billed once per patient per 7-day period, not per visit and not per dose. G2067 covers methadone. G2068 covers oral buprenorphine, including buprenorphine-naloxone combination products. G2069 covers injectable buprenorphine, billable no more than once every four weeks. G2073 covers naltrexone, also capped at once every four weeks. When a patient's weekly episode includes no drug administration at all, typically early in treatment or during a lapse, G2074 or G2075 apply instead, and CMS requires at least one non-drug service, like counseling or toxicology, to be billed alongside G2074 to justify it. A separate code, G0533, covers injectable buprenorphine under a slightly different billing structure, and as of October 6, 2025, modifier 59 can support billing it more than once in a single 7-day period when the clinical picture genuinely supports it.

Layered on top of the weekly bundle are add-on codes for everything the bundle doesn't already cover: G2076 for intake activities on a new patient starting treatment, G2077 for a periodic assessment that can ride alongside the weekly code, and G2080 for counseling beyond what the base bundle includes, billed in 30-minute increments. G0534, G0535 and G0536 cover care coordination, patient navigation and peer recovery support, each in additional 30-minute units. None of these add-ons replace the weekly bundle code; they supplement it, and billing them without an underlying weekly bundle claim for that same patient and period is itself a documentation gap worth catching before a MAC catches it for you.

Take-Home Medication Billing: Where Most Errors Start

Take-home supply codes exist because not every patient visits an OTP daily for dosing, and this is the single most common place OTP billing goes wrong. G2078 covers an additional take-home supply of methadone, and G2079 covers oral buprenorphine, used specifically alongside G2068. Each covers up to seven additional days of medication, capped at three units, which works out to a one-month maximum when combined correctly with the weekly bundle. CMS limits these add-ons to no more than three times per month, and critically, they can never be billed for dates of service that overlap with the weekly bundle codes G2067 through G2073 for that same patient. A claim that bills a take-home supply code and a weekly bundle code for overlapping dates is billing for the same medication twice under two different code families, which is precisely the pattern an auditor is trained to flag.

Naloxone and nalmefene codes carry their own frequency limits that run on a separate track from the OUD treatment bundle itself. G2215 (nasal naloxone), G2216 (injectable naloxone) and G1028 (nasal naloxone, 2-pack) are each limited to once every 30 days unless a program documents medical necessity for an additional supply, and G2216 specifically requires the dosage reported in the units field, rounded to the nearest whole number with a 1 mg minimum. G0532, the nasal nalmefene code, follows the same 30-day limit and can't be billed twice for the same patient on the same date of service. None of these limits are complicated individually; they become a compliance problem when a program's EHR template doesn't enforce them and billing staff are left to track overlapping date ranges by hand across a large patient panel.

OIG Audit Findings and What the 36-Month Lookback Means for Your Claims

OIG's $178 million improper-payment finding (A-09-22-03005) came with six recommendations to CMS, including having Medicare Administrative Contractors review OTP claims specifically for the kind of frequency and bundling errors described above. A later OIG review, published around October 2025, estimated that Medicare could have saved roughly $301.5 million if OTP bundled payment rates had been better matched to the actual services enrollees received, a finding that points squarely at programs billing full weekly bundles for episodes where fewer services were actually delivered. A separate Medicaid-focused OIG review of OTP billing (W-00-24-31523) left two CMS recommendations open as of its most recent update, which means federal attention on this category hasn't closed out; it's ongoing across both Medicare and Medicaid.

The standard 36-month lookback period applies to OTP claims the same way it applies to any other Medicare audit. That means every weekly bundle, take-home add-on and naloxone claim your program has submitted over the last three years is inside the window a MAC or OIG reviewer could pull, regardless of when the specific audit letter arrives. Programs that have been billing take-home codes without tracking date overlaps, or billing G2074 without a qualifying non-drug service attached, carry that exposure across the full lookback, not just from whenever the error gets noticed internally.

What Actually Triggers OTP Billing Eligibility, and What Happens When It Lapses

OTP billing doesn't run through a traditional prior authorization process the way a specialty drug or imaging study does. Instead, the gate is the program's own certification: SAMHSA certification, DEA registration specific to opioid treatment, and state opioid treatment authority approval all have to be active and on file before Medicare will pay a single weekly bundle claim. The request to even become a Medicare-billing OTP requires submitting that certification package to your MAC, and a lapse in any one of the three, not just an expired DEA registration but also a missed SAMHSA renewal cycle, can halt claims processing for the entire program, not just one patient.

When a claim denies under this structure, it's rarely a clinical appeal in the usual sense; it's almost always a certification or frequency-limit mismatch, which means the fix is administrative, not clinical. Track certification and registration expiration dates on a calendar separate from your general compliance calendar, with a 90-day buffer before each renewal deadline, not the 30-day buffer many programs default to. Running out that buffer against a single shared spreadsheet, rather than relying on any one person's memory of when DEA registrations expire, is the single most effective way to avoid a billing gap that has nothing to do with patient care and everything to do with paperwork timing.

Our substance use disorder billing guide covers the broader SUD billing landscape OTPs sit inside, and our RAC audits guide walks through what a federal claims review actually looks like once it starts.

Frequently Asked Questions About OTP Billing

What HCPCS codes does an Opioid Treatment Program bill Medicare?

OTPs bill drug-specific weekly bundles: G2067 for methadone, G2068 for oral buprenorphine, G2069 for injectable buprenorphine, G2073 for naltrexone, and G2074 or G2075 when no drug is given during the episode. Add-on codes cover take-home supplies (G2078, G2079), intake (G2076), periodic assessment (G2077), counseling (G2080), and naloxone (G2215, G2216, G1028). Each weekly bundle bills once per 7-day period per patient.

How many times can an OTP bill take-home medication supply codes in a month?

No more than three times per month, and never for dates of service that overlap with the weekly bundle codes (G2067-G2073) for that same patient. Each take-home supply code (G2078 for methadone, G2079 for oral buprenorphine) covers up to seven additional days of medication, with a cap of three units, so the monthly structure tops out at one weekly bundle plus three take-home add-ons per patient.

How much has Medicare overpaid for OTP services, according to OIG?

OIG found Medicare made roughly $178 million in potentially improper payments to OTPs for opioid use disorder treatment services (report A-09-22-03005). A separate OIG review found Medicare could have saved about $301.5 million if OTP bundled payment rates had more closely matched the services enrollees actually received, and recommended CMS have Medicare Administrative Contractors review OTP claims for compliance.