DAW stands for “Dispense as Written,” a designation used on prescriptions to tell the pharmacy whether or not it can substitute a generic version of a medication. When a prescriber writes DAW on a prescription, they’re instructing the pharmacist to fill it with the exact brand-name drug specified, not a cheaper generic equivalent. Behind the scenes, DAW is also a numeric code (0 through 9) that pharmacies submit to insurance companies when processing claims, communicating who requested the brand-name drug and why.
How DAW Works in Practice
In most states, pharmacists are allowed (and sometimes required) to substitute a less expensive generic drug when one is available. DAW overrides that default. If your doctor believes you need a specific brand-name medication, they can mark the prescription “Dispense as Written” or “Brand Medically Necessary,” which prevents the pharmacy from swapping in a generic.
On paper prescriptions, this traditionally meant the doctor would write “DAW” or sign on a specific line indicating no substitution. With electronic prescribing, the same instruction is transmitted digitally. States like New York explicitly allow electronic signatures paired with an electronic DAW designation, and most other states have similar provisions.
The DAW Codes (0 Through 9)
When a pharmacy submits a claim to your insurance, it includes a single-digit DAW code, formally called the “Product Selection Code” under the NCPDP Telecommunication Standard used across the industry. Each number tells the insurer something different about why a brand-name drug was dispensed instead of a generic.
- DAW 0: No product selection indicated. The pharmacist may substitute a generic if one is available. This is the most common code and the default on most prescriptions.
- DAW 1: Substitution not allowed by the prescriber. The doctor has specifically required the brand-name product. This is the code that carries the most weight with insurance companies.
- DAW 2: Substitution allowed, but the patient requested the brand. You asked for the brand name even though the doctor didn’t require it.
- DAW 3: Substitution allowed, but the pharmacist selected the brand product.
- DAW 4: Substitution allowed, but the generic is not in stock.
- DAW 5: Substitution allowed, but the brand drug is dispensed at a price equal to or less than the generic.
- DAW 6: Override used by the pharmacist based on state law or regulation.
- DAW 7: Substitution not allowed because the brand drug is mandated by law.
- DAW 8: Substitution allowed, but a generic is not available in the marketplace.
- DAW 9: Other, covering situations not described by codes 1 through 8.
Why DAW 1 Matters Most for Insurance
Of all ten codes, DAW 1 is the one insurance plans pay closest attention to. It signals that the prescriber has made a medical judgment that the patient needs the brand-name drug specifically. Many insurance plans, including Medicaid programs, require prior authorization before they’ll cover a brand-name drug when a generic equivalent exists. A claim submitted with DAW 1 for a brand-name medication that has generic alternatives may be rejected with a message asking the pharmacy to either use the available generic or obtain prior authorization confirming the brand is medically necessary.
Claims submitted with DAW codes 0 or 2 through 9 typically don’t trigger this specific rejection. However, those claims can still be denied for other coverage reasons, such as the drug not being on the plan’s formulary or quantity limits being exceeded. The practical takeaway: DAW 1 is the only code that truly restricts substitution from the insurer’s perspective, and it often requires extra paperwork to get approved.
How DAW Affects Your Out-of-Pocket Cost
Generic drugs cost significantly less than their brand-name counterparts, and insurance plans build their copay structures around that difference. When a prescription is filled with a generic (DAW 0), you typically pay the lowest copay tier. When a brand-name drug is dispensed because the doctor required it (DAW 1), your plan may cover it at a higher copay tier, or it may require prior authorization before covering it at all.
Things get more expensive when you’re the one requesting the brand. If you ask for a brand-name drug when a generic is available (DAW 2), many insurance plans will charge you the brand copay plus the cost difference between the brand and generic versions. Some plans won’t cover the brand at all in this scenario, leaving you to pay the full price. The logic is straightforward: if there’s no medical reason for the brand, the plan doesn’t want to absorb the extra cost.
If your doctor does believe the brand is necessary, the path forward usually involves the doctor’s office submitting a prior authorization request to your insurance. This documents the clinical reasoning, such as a patient having a bad reaction to the generic’s inactive ingredients or not responding well to the generic formulation.
State Laws Shape How Substitution Works
Every state has its own pharmacy laws governing generic substitution, and these laws create the legal framework that DAW codes operate within. State regulations address two main questions: whether pharmacists are required or simply permitted to substitute generics, and whether patient consent is assumed or must be explicitly obtained before a switch happens.
In some states, pharmacists must substitute the generic unless the prescriber has written DAW. In others, substitution is allowed but not mandatory. Regardless of the state, you as the patient can always refuse a generic substitution, though doing so will likely affect what you pay. These laws don’t regulate what doctors write on the prescription. A separate set of rules governs how prescribers can block generic substitution, which is where DAW designations come in.
What This Means If You See DAW on Your Prescription
If your prescription or pharmacy receipt shows a DAW code other than 0, it means something prevented the usual generic substitution. The most common scenario is DAW 1, where your doctor has decided the brand-name version is important for your care. This might happen with medications where small differences between the brand and generic formulations could affect how the drug works for you, such as certain thyroid medications, anti-seizure drugs, or narrow therapeutic index drugs where precise dosing is critical.
If you’re paying more than expected for a medication, the DAW code on your pharmacy receipt can help explain why. A DAW 2, for instance, means the brand was dispensed at your own request, and switching to the generic could lower your cost. A DAW 1 means your doctor made that call, and if cost is a concern, it’s worth asking them whether a generic would be appropriate in your case. Sometimes the original DAW 1 designation was carried over from an older prescription and may no longer be necessary.