Why does this page start at 473 mL?

NADAC prices this product per ML. The FDA NDC Directory’s package description gives 473 mL in one package for this product’s NDC (“473 mL in 1 BOTTLE (28595-804-16)”), so the card starts at one package: 473 ML. Change it to match your prescription.

HISTEX-DM SYRUP

FDA nonproprietary name: dextromethorphan hydrobromide, phenylephrine hydrochloride, and triprolidine hydrochloride

For 473 mL

Pharmacies pay

$35.44 filed

473 × $0.07493 per ML

CMS NADAC · nadac-national-average-drug-acquisition-cost-20261014.csv · eff. 2026-09-23 · as of 2026-10-14 · retrieved 2026-10-17

Medicare

We don’t know yet

No Medicare reference price. Part D: OpenBill did not match this NDC to a usable Medicare Part D spending row. Either Part D has none for it, or the rows that share its name could not safely be tied to it (for example, they mix units, routes or release forms, or the drug is sold over the counter, which Part D does not cover). Part B: This NDC is not in the current quarter’s Medicare Part B NDC-HCPCS crosswalk, so it has no Part B payment limit.

The spread

We don’t know yet

There is no Medicare figure to compare with, so there is no spread.

Cost-plus estimate

$45.76 estimated

$35.44 + $5.32 (15%) + $5.00 fee per fill = $45.76

This is a model, not a price any pharmacy quoted. Shipping is not included. How it is worked out

OpenBill calculation · nadac-national-average-drug-acquisition-cost-20261014.csv · NADAC eff. 2026-09-23 (file of 2026-10-14, retrieved 2026-10-17)

Open the interactive card Change the quantity, type what you were charged, and see every record in full.

What it is

HISTEX-DM SYRUP is how the CMS NADAC file names this product. The FDA NDC Directory lists it as dextromethorphan hydrobromide, phenylephrine hydrochloride, and triprolidine hydrochloride, under the trade name “HISTEX-DM”.

FDA gives its dosage form as syrup and its route as oral.

The labeler, the company named on the label, is Allegis Pharmaceuticals, LLC.

FDA lists it under 3 Established Pharmacologic Classes: alpha-1 Adrenergic Agonist, Sigma-1 Agonist and Uncompetitive N-methyl-D-aspartate Receptor Antagonist.

The NADAC file of 2026-10-14 prices it under one NDC (National Drug Code), 28595-0804-16.

NADAC classes it as a generic drug (rate-setting class G), and marks it as sold over the counter.

What pharmacies pay

Pharmacies pay $35.44 for 473 mL (473 × $0.07493 per ML, rounded to the cent), by the CMS NADAC file of 2026-10-14; that price took effect on 2026-09-23. That is what pharmacies pay their suppliers, not what they charge you.

NADAC’s explanation codes for it: 1, calculated from the most recently completed pharmacy survey; 5, calculated based on package size.

What NADAC measures · NADAC explanation codes

The NDC

28595-0804-16 · Allegis Pharmaceuticals, LLC · $0.07493 per ML · eff. 2026-09-23 filed

Compared with its class

Its NADAC price is $0.07493 per ML filed.

Of the 30 other products in FDA’s alpha-1 Adrenergic Agonist class priced per ML, 7 have a higher middle NADAC price and 23 a lower one. The one in the middle is RYNEX DM LIQUID, at $0.05121 per ML filed (eff. 2026-09-23).

Of the 63 other products in FDA’s Sigma-1 Agonist class priced per ML, 5 have a higher middle NADAC price and 58 a lower one. The one in the middle is GNP TUSSIN LONG-ACTING LIQUID, at $0.02263 per ML filed (eff. 2026-09-23).

Of the 63 other products in FDA’s Uncompetitive N-methyl-D-aspartate Receptor Antagonist class priced per ML, 5 have a higher middle NADAC price and 58 a lower one. The one in the middle is GNP TUSSIN LONG-ACTING LIQUID, at $0.02263 per ML filed (eff. 2026-09-23).

Prices are compared per unit, whatever the strength or dose, and a class is not a list of substitutes.

CMS NADAC · nadac-national-average-drug-acquisition-cost-20261014.csv · eff. 2026-09-23 · as of 2026-10-14 · retrieved 2026-10-17

How the class comparison works

What Medicare paid

We don’t know yet; the card above says why.

Which Medicare figure OpenBill compares · How Part D is matched · How Part B is matched

What to ask at the counter

None of these figures is your price: what you pay depends on your pharmacy, your insurance, coupons and discounts.

What is your cash price for 473 mL? Is it lower than what I would pay through my insurance?
It is sold over the counter, so shelf prices vary from store to store: what does it cost per unit here?
How much is in the package I am getting? This page uses 473 mL; your package may hold a different amount.
These are questions about price, not medical advice. Do not change or stop a medicine without talking to your prescriber or pharmacist.

Questions

Why does this page start at 473 mL?: NADAC prices this product per ML. The FDA NDC Directory’s package description gives 473 mL in one package for this product’s NDC (“473 mL in 1 BOTTLE (28595-804-16)”), so the card starts at one package: 473 ML. Change it to match your prescription.

Its pharmacologic classes

alpha-1 Adrenergic Agonist 86 products
Sigma-1 Agonist 111 products
Uncompetitive N-methyl-D-aspartate Receptor Antagonist 111 products