Promethazine is an old, cheap generic that patients keep getting surprised by. Medicare Part D covered 1.30 million promethazine hydrochloride claims in 2024 at an average of $10.15 each. The medicine inside those claims costs a pharmacy about four and a half cents per tablet.
The surprise comes from form. Promethazine is sold as a tablet, an oral syrup, a rectal suppository and an injectable vial, and those four products span a price range of more than 300 to 1. Two people handed the same diagnosis and the same drug name can walk out of the pharmacy with a $6 bill and a $90 bill.
This guide covers the cash price of plain promethazine hydrochloride, the antiemetic and antihistamine version prescribed for nausea, vomiting, motion sickness and allergy symptoms. Combination cough products containing promethazine are separate drug listings with separate pricing and are not covered here. Every figure below is dated, and the underlying federal acquisition data is refreshed weekly, so re-check before you rely on a specific number months from now.
What Does Promethazine Cost Without Insurance?
The Low column is what a pharmacy pays to acquire the drug, from the CMS National Average Drug Acquisition Cost file with an August 19, 2026 effective date, still present in the September 2, 2026 weekly release. The Average and High columns are cash-payer prices read on September 4, 2026.
| Promethazine presentation | Low (pharmacy cost) | Average (cash price) | High (retail or brand) |
|---|---|---|---|
| 25 mg tablets, 30 count | $1.36 | $7.99 | $24.97 |
| 12.5 mg tablets, 30 count | $1.60 | $5.71 | $10.00 (10 count) |
| 50 mg tablets, 30 count | $2.36 | $6.55 | $15.00 (20 count) |
| 25 mg suppositories, 30 count | $61.31 | $89.21 | $752.07 (brand Promethegan, 50 mg) |
| 6.25 mg/5 mL syrup, 30 mL | $1.27 | $6.12 | $55.00 (full bottle) |
The tablet row is the one most people need. Cost Plus Drugs listed thirty 25 mg tablets at $5.83 on September 4, 2026 against its own stated retail comparison of $18.00, with a standard shipping charge added at checkout (listed as $5.25 in the cost breakdown on that page). SingleCare quoted $7.99 for the same fill with its card and put the typical price without a card at $24.97. HealthWarehouse listed twelve 25 mg tablets at $9.24 with free shipping available.
Sources disagree on the top of the tablet range, and the disagreement is instructive. Drugs.com’s own price comparison listed a HealthWarehouse price of $9.00 for twelve 25 mg tablets on September 4, 2026 while HealthWarehouse’s own product page showed $9.24 the same day. Treat any single quote as a snapshot and price your specific fill before you commit.
What Drives the Price
Which form the prescription is written for
This is the whole story. In the August 19, 2026 acquisition file a 25 mg promethazine tablet costs a pharmacy $0.04544 and a 25 mg suppository costs $2.04375, a gap of about 45 times. A 12.5 mg suppository costs $1.85858. The injectable vial at 25 mg per mL costs $1.75582 per milliliter and the ampule version costs $1.31331.
Strength
Unusually for a generic, the middle strength is not the cheapest per tablet. The 12.5 mg tablet costs a pharmacy more per unit ($0.05342) than the 25 mg tablet ($0.04544), because the 25 mg is the volume strength. If your prescriber is flexible on strength, ask.
Pharmacy markup
At four and a half cents of drug per tablet, essentially the entire retail price is dispensing cost. That is why the same 30-tablet fill runs $5.83 at a mail-order pharmacy and $24.97 as an average retail price. Nothing about the medicine changed between those two numbers.
Whether it is given in a clinic
A shot is priced as a service. In 2024 CMS claims data covering 8,339 providers, HCPCS J2550 (promethazine injection, up to 50 mg) carried an average submitted charge of $15.52 in the office setting against a Medicare allowed amount of $3.20. The intramuscular administration code 96372 carried an average submitted charge of $55.33 against a $13.42 allowed amount. The vial itself costs the practice under $2.
Quantity and dispensing fees
Because the drug itself is close to free, the dispensing fee dominates, and that fee is charged once per fill regardless of size. Cost Plus Drugs publishes its own arithmetic: on the 25 mg tablet page the September 4, 2026 breakdown showed $0.72 of manufacturing cost, an $0.11 markup and $5.00 of pharmacy labor. Doubling the tablet count barely moves the labor line, which is why 90-count fills price so much lower per tablet than 30-count fills.
Brand labeling on the suppositories
Suppositories are where brand names still cost real money. Drugs.com listed a Cost Plus Drugs price of $752.07 for thirty 50 mg Promethegan suppositories on September 4, 2026, against $89.21 for thirty generic 25 mg suppositories. Medicare Part D data agrees on the direction: an average of $104.24 per Promethegan claim in 2024 against $10.15 per generic claim.
Cash Price vs. Insurance
For tablets, paying cash usually wins. A typical deductible-phase copay runs $10 to $15, and the mail-order or discount-card price for a 30-day fill is often below that. Pharmacies can quote you the cash price on request, and the federal ban on pharmacy gag clauses means they cannot be stopped from telling you.
The exception is the suppository. At $89.21 or more per pack, a suppository fill is expensive enough that a covered copay may genuinely be cheaper, and it is also expensive enough that the fill counts meaningfully toward a deductible. If you have coverage and the prescription is for suppositories, run it through the plan first and compare.
Cash fills paid outside a plan generally do not count toward your deductible or out-of-pocket maximum. That matters less on a $6 drug than it does on a $900 one, but it is worth knowing before you build a habit of paying cash for everything.
How to Pay Less
Ask whether tablets will work. The gap between a tablet course and a suppository course on this drug is roughly $80 for the same active ingredient. That is a conversation for your prescriber, but it is worth having before the prescription is sent.
Compare discount cards against the counter price. The retail-to-card spread on promethazine is roughly three to one. Our GoodRx vs. SingleCare comparison explains how the two cards differ, and our fair price checker shows what a defensible cash price looks like before you walk in.
Use mail order for standing prescriptions. Cost Plus Drugs listed thirty 25 mg tablets at $5.83 on September 4, 2026 with shipping added at checkout. HealthWarehouse ships as well. Neither helps if you need the medicine tonight, so keep a local price in mind too.
Ask for a larger quantity. Drugs.com listed a dirxhealth price of $13.10 for ninety 12.5 mg tablets on September 4, 2026, about 15 cents a tablet, against roughly 20 cents at a 30-count fill. Fewer dispensing fees means a lower unit price.
Get the itemized bill if you were given a shot. A promethazine injection given in an urgent care or emergency department shows up as a drug line and an administration line, and both are commonly billed well above the allowed amounts in the CMS data above. Start with reading an itemized hospital bill, then use how to negotiate medical bills to challenge the markup.
Find a sliding-scale prescriber if you do not have one. Federally qualified health centers charge on income and many dispense common generics in house. See free clinics and sliding-scale care.
Bottom Line
A month of generic promethazine tablets should cost a cash payer somewhere between $6 and $25 in September 2026. If you are quoted meaningfully more than that for tablets, the price is coming from the pharmacy counter, not from the medicine, and a different pharmacy or a discount card will fix it.
Suppositories are the genuine expense on this drug at $17 to $89 a pack, and a shot in a clinic is priced as a visit rather than as a dose. For other cash-priced nausea and neurology generics, see our guides to Zofran and ondansetron costs, topiramate costs and prednisone costs.