Q0166 — Granisetron hydrochloride, 1 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 24 hour dosage regimen
Q0166 is a HCPCS Level II code for granisetron hydrochloride, 1 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 24 hour dosage regimen. It belongs to the Temporary Codes section. Whether Medicare pays it depends on the coverage rule below.
Medicare coverage: Special coverage instructions apply
There are published conditions attached to this code. Check the applicable coverage policy before billing it: the code being valid is not the same as the service being covered.
From the coverage field of the CMS Alpha-Numeric HCPCS File, release 2026Q3-Jul. This states Medicare’s position on the code, not on your particular claim.
Physician fee schedule statusX
Statutory exclusion. The item or service is not within the statutory definition of 'physician services', so the fee schedule never pays it.
Global period: XXX
Want the dollar amount for your locality? The fee calculator applies your GPCI and the current conversion factor.
Medically Unlikely Edits — units per day
The most units of Q0166 Medicare will pay on one date of service. Bill more on a single line and it is denied. The limit is not the same in every setting, so the row that matters is the one matching the claim you are building.
- practitioner
- 0 — never payable MAI 3 — Date of Service Edit: Clinical · Oral Medication; Not Payable
- outpatient
- 2 units MAI 3 — Date of Service Edit: Clinical · Prescribing Information
- DME supplier
- 2 units MAI 3 — Date of Service Edit: Clinical · Prescribing Information
The adjudication indicator decides whether exceeding the limit is worth appealing at all: MAI 1 is a line edit you can support with documentation, MAI 3 is a date-of-service edit that is also appealable, and MAI 2 is absolute — no documentation overrides it. CMS MUE 2026Q3.
The CMS record for Q0166
- Long descriptor
- Granisetron hydrochloride, 1 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 24 hour dosage regimen
- Short descriptor
- Granisetron hcl 1 mg oral
- Added
- April 1, 1998
- BETOS
- O1D
- Pricing indicator
- 51 — Other
The official wording. This is what the code means.
CMS's 28-character form, which is what shows up on a remittance advice.
When CMS introduced the code.
Berenson-Eggers Type of Service — CMS's own analytic grouping.
Drugs.
Codes adjacent to Q0166
HCPCS has no hierarchy — related items simply sit next to each other in the numbering. If Q0166 is not quite right, the correct code is very often within a few positions of it.
- Q0138Injection, ferumoxytol, for treatment of iron deficiency anemia, 1 mg (non-esrd use)
- Q0139Injection, ferumoxytol, for treatment of iron deficiency anemia, 1 mg (for esrd on dialysis)
- Q0144Azithromycin dihydrate, oral, capsules/powder, 1 gram
- Q0155Dronabinol (syndros), 0.1 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
- Q0161Chlorpromazine hydrochloride, 5 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
- Q0162Ondansetron 1 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
- Q0163Diphenhydramine hydrochloride, 50 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at time of chemotherapy treatment not to exceed a 48 hour dosage regimen
- Q0164Prochlorperazine maleate, 5 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
- Q0167Dronabinol, 2.5 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
- Q0169Promethazine hydrochloride, 12.5 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
- Q0173Trimethobenzamide hydrochloride, 250 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
- Q0174Thiethylperazine maleate, 10 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimenterminated
- Q0175Perphenazine, 4 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
- Q0177Hydroxyzine pamoate, 25 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
- Q0180Dolasetron mesylate, 100 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 24 hour dosage regimen
- Q0181Unspecified oral dosage form, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for a iv anti-emetic at the time of chemotherapy treatment, not to exceed a 48 hour dosage regimen
Questions about Q0166
What is HCPCS code Q0166?
Q0166 is a HCPCS Level II code for granisetron hydrochloride, 1 mg, oral, fda approved prescription anti-emetic, for use as a complete therapeutic substitute for an iv anti-emetic at the time of chemotherapy treatment, not to exceed a 24 hour dosage regimen. It sits in the Temporary Codes section.
Does Medicare cover Q0166?
The CMS HCPCS file marks Q0166 as "Special coverage instructions apply". There are published conditions attached to this code. Check the applicable coverage policy before billing it: the code being valid is not the same as the service being covered.
How is Q0166 paid under the physician fee schedule?
Q0166 carries PFS status code X. Statutory exclusion. The item or service is not within the statutory definition of 'physician services', so the fee schedule never pays it.