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    Home / Pharmacy rules by state / Generic substitution by state

    Generic substitution laws by state: 2026 guide

    Checked against each state's rules: October 2026

    Short answer

    Every state lets a pharmacist dispense an FDA-rated equivalent generic in place of a brand-name drug unless the prescriber indicates the brand is medically necessary. States differ on whether substitution is required when it lowers the price, how a prescriber blocks it, whether you must be told or can refuse, and how biosimilars are handled. The table quotes each state’s rules.

    Generic substitution in every state

    Each row quotes the opening of that state's guide on substitution, which cites the state's own pharmacy law. Follow the link for the full rules, including notification and any exceptions.

    • Alabama
      An Alabama pharmacist may substitute a generic equivalent unless the prescriber has written “medically necessary”, “dispense as written” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    • Alaska
      An Alaska pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Arizona
      An Arizona pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution and the patient may refuse it.
    • Arkansas
      An Arkansas pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • California
      A California pharmacist may dispense a generic equivalent in place of the brand written on a prescription unless the prescriber has indicated in their own handwriting, or electronically, that no substitution is allowed. The pharmacist must tell the patient that a substitution was made and must note it on the label.
    • Colorado
      A Colorado pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written” on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Connecticut
      A Connecticut pharmacist may substitute a generic equivalent unless the prescriber has indicated “brand medically necessary” on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Delaware
      A Delaware pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Florida
      Florida law directs a pharmacist to substitute a less expensive generic equivalent unless the prescriber has written “medically necessary” on the prescription, or indicated it electronically, or the patient asks for the brand. The pharmacist must tell the patient about the substitution and record it.
    • Georgia
      A Georgia pharmacist may substitute a generic equivalent unless the prescriber has written “brand necessary” or “brand medically necessary” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and may not substitute if the patient objects.
    • Hawaii
      A Hawaii pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required; Hawaii publishes a list of drugs that may not be substituted. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Idaho
      An Idaho pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Illinois
      An Illinois pharmacist may substitute a generic equivalent unless the prescriber has indicated that the brand is required, by writing “may not substitute” or the equivalent, or electronically. The pharmacist must tell the patient about the substitution and record the product dispensed.
    • Indiana
      An Indiana pharmacist may substitute a generic equivalent unless the prescriber has written “brand medically necessary” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    • Iowa
      An Iowa pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Kansas
      A Kansas pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Kentucky
      A Kentucky pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand must be dispensed. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Louisiana
      A Louisiana pharmacist may substitute a generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Maine
      A Maine pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Maryland
      A Maryland pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution and pass on the saving; a patient may ask for the brand and pay for it.
    • Massachusetts
      Massachusetts requires a pharmacist to substitute a less expensive generic equivalent unless the prescriber has written “no substitution” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution.
    • Michigan
      A Michigan pharmacist may substitute a generic equivalent unless the prescriber has written “dispense as written” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and the substituted product must cost the patient less.
    • Minnesota
      A Minnesota pharmacist may substitute a generic equivalent unless the prescriber has written “dispense as written” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and the patient may refuse it.
    • Mississippi
      A Mississippi pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Missouri
      A Missouri pharmacist may substitute a generic equivalent unless the prescriber has written “dispense as written” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    • Montana
      A Montana pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Nebraska
      A Nebraska pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Nevada
      A Nevada pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand must be dispensed. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • New Hampshire
      A New Hampshire pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • New Jersey
      New Jersey requires a pharmacist to substitute a less expensive generic equivalent unless the prescriber has indicated “do not substitute” by signing the appropriate line or box on the prescription, or electronically. The pharmacist must tell the patient about the substitution and pass on the saving.
    • New Mexico
      A New Mexico pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • New York
      New York requires a pharmacist to substitute a less expensive generic equivalent unless the prescriber has indicated “dispense as written” in the box provided on the prescription or electronically. The pharmacist must tell the patient about the substitution.
    • North Carolina
      A North Carolina pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written”, “brand medically necessary” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution.
    • North Dakota
      A North Dakota pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Ohio
      An Ohio pharmacist may select a generically equivalent drug in place of the brand prescribed unless the prescriber has handwritten “dispense as written” or the equivalent on the prescription, or indicated it electronically. The pharmacist must tell the patient that a substitution was made and the saving must be passed on.
    • Oklahoma
      An Oklahoma pharmacist may substitute a generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Oregon
      An Oregon pharmacist may substitute a generic equivalent unless the prescriber has indicated “no substitution” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Pennsylvania
      Under Pennsylvania’s Generic Equivalent Drug Law, a pharmacist may substitute a generic equivalent unless the prescriber has written “brand medically necessary” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and must pass on the saving.
    • Rhode Island
      A Rhode Island pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • South Carolina
      A South Carolina pharmacist may substitute a generic equivalent unless the prescriber has indicated “brand medically necessary” or “dispense as written” on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    • South Dakota
      A South Dakota pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Tennessee
      A Tennessee pharmacist may substitute a generic equivalent unless the prescriber has written “dispense as written”, “medically necessary” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    • Texas
      A Texas pharmacist may substitute a generic equivalent unless the prescriber has written “brand necessary” or “brand medically necessary” on the prescription, or indicated the equivalent electronically. The pharmacist must tell the patient that a less expensive generic is available and may be substituted, and the patient can refuse the substitution and pay the brand price.
    • Utah
      A Utah pharmacist may substitute a generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Vermont
      A Vermont pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Virginia
      A Virginia pharmacist may substitute a generic equivalent unless the prescriber has written “brand medically necessary” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and record the product dispensed.
    • Washington
      A Washington pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written” on the prescription or electronically. The pharmacist must tell the patient about the substitution, and a patient may refuse it and pay for the brand.
    • Washington, D.C.
      A District of Columbia pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • West Virginia
      A West Virginia pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Wisconsin
      A Wisconsin pharmacist may substitute a generic equivalent unless the prescriber has indicated “no substitutions” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    • Wyoming
      A Wyoming pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    Generic substitution rules by state, October 2026
    StateWhat the state guide says
    AlabamaAn Alabama pharmacist may substitute a generic equivalent unless the prescriber has written “medically necessary”, “dispense as written” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    AlaskaAn Alaska pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    ArizonaAn Arizona pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution and the patient may refuse it.
    ArkansasAn Arkansas pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    CaliforniaA California pharmacist may dispense a generic equivalent in place of the brand written on a prescription unless the prescriber has indicated in their own handwriting, or electronically, that no substitution is allowed. The pharmacist must tell the patient that a substitution was made and must note it on the label.
    ColoradoA Colorado pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written” on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    ConnecticutA Connecticut pharmacist may substitute a generic equivalent unless the prescriber has indicated “brand medically necessary” on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    DelawareA Delaware pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    FloridaFlorida law directs a pharmacist to substitute a less expensive generic equivalent unless the prescriber has written “medically necessary” on the prescription, or indicated it electronically, or the patient asks for the brand. The pharmacist must tell the patient about the substitution and record it.
    GeorgiaA Georgia pharmacist may substitute a generic equivalent unless the prescriber has written “brand necessary” or “brand medically necessary” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and may not substitute if the patient objects.
    HawaiiA Hawaii pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required; Hawaii publishes a list of drugs that may not be substituted. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    IdahoAn Idaho pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    IllinoisAn Illinois pharmacist may substitute a generic equivalent unless the prescriber has indicated that the brand is required, by writing “may not substitute” or the equivalent, or electronically. The pharmacist must tell the patient about the substitution and record the product dispensed.
    IndianaAn Indiana pharmacist may substitute a generic equivalent unless the prescriber has written “brand medically necessary” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    IowaAn Iowa pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    KansasA Kansas pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    KentuckyA Kentucky pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand must be dispensed. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    LouisianaA Louisiana pharmacist may substitute a generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    MaineA Maine pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    MarylandA Maryland pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution and pass on the saving; a patient may ask for the brand and pay for it.
    MassachusettsMassachusetts requires a pharmacist to substitute a less expensive generic equivalent unless the prescriber has written “no substitution” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution.
    MichiganA Michigan pharmacist may substitute a generic equivalent unless the prescriber has written “dispense as written” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and the substituted product must cost the patient less.
    MinnesotaA Minnesota pharmacist may substitute a generic equivalent unless the prescriber has written “dispense as written” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and the patient may refuse it.
    MississippiA Mississippi pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    MissouriA Missouri pharmacist may substitute a generic equivalent unless the prescriber has written “dispense as written” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    MontanaA Montana pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    NebraskaA Nebraska pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    NevadaA Nevada pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand must be dispensed. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    New HampshireA New Hampshire pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    New JerseyNew Jersey requires a pharmacist to substitute a less expensive generic equivalent unless the prescriber has indicated “do not substitute” by signing the appropriate line or box on the prescription, or electronically. The pharmacist must tell the patient about the substitution and pass on the saving.
    New MexicoA New Mexico pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    New YorkNew York requires a pharmacist to substitute a less expensive generic equivalent unless the prescriber has indicated “dispense as written” in the box provided on the prescription or electronically. The pharmacist must tell the patient about the substitution.
    North CarolinaA North Carolina pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written”, “brand medically necessary” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution.
    North DakotaA North Dakota pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    OhioAn Ohio pharmacist may select a generically equivalent drug in place of the brand prescribed unless the prescriber has handwritten “dispense as written” or the equivalent on the prescription, or indicated it electronically. The pharmacist must tell the patient that a substitution was made and the saving must be passed on.
    OklahomaAn Oklahoma pharmacist may substitute a generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    OregonAn Oregon pharmacist may substitute a generic equivalent unless the prescriber has indicated “no substitution” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    PennsylvaniaUnder Pennsylvania’s Generic Equivalent Drug Law, a pharmacist may substitute a generic equivalent unless the prescriber has written “brand medically necessary” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and must pass on the saving.
    Rhode IslandA Rhode Island pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    South CarolinaA South Carolina pharmacist may substitute a generic equivalent unless the prescriber has indicated “brand medically necessary” or “dispense as written” on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    South DakotaA South Dakota pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    TennesseeA Tennessee pharmacist may substitute a generic equivalent unless the prescriber has written “dispense as written”, “medically necessary” or the equivalent on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it.
    TexasA Texas pharmacist may substitute a generic equivalent unless the prescriber has written “brand necessary” or “brand medically necessary” on the prescription, or indicated the equivalent electronically. The pharmacist must tell the patient that a less expensive generic is available and may be substituted, and the patient can refuse the substitution and pay the brand price.
    UtahA Utah pharmacist may substitute a generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    VermontA Vermont pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    VirginiaA Virginia pharmacist may substitute a generic equivalent unless the prescriber has written “brand medically necessary” on the prescription or indicated it electronically. The pharmacist must tell the patient about the substitution and record the product dispensed.
    WashingtonA Washington pharmacist may substitute a generic equivalent unless the prescriber has indicated “dispense as written” on the prescription or electronically. The pharmacist must tell the patient about the substitution, and a patient may refuse it and pay for the brand.
    Washington, D.C.A District of Columbia pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    West VirginiaA West Virginia pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    WisconsinA Wisconsin pharmacist may substitute a generic equivalent unless the prescriber has indicated “no substitutions” or the equivalent on the prescription or electronically. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.
    WyomingA Wyoming pharmacist may substitute a less expensive generic equivalent unless the prescriber has indicated on the prescription, or electronically, that the brand is required. The pharmacist must tell the patient about the substitution, and the patient may refuse it and pay for the brand.

    How generic substitution works

    A pharmacist can substitute only a generic the FDA rates as therapeutically equivalent to the brand, shown by an AB rating in the FDA’s Orange Book. It has the same active ingredient, strength, dosage form and route, and is shown to work the same way in the body. The tablet can look different and contain different inactive ingredients.

    The prescriber can prevent substitution by indicating that the brand is required, using wording or a checkbox set by state law, such as "dispense as written" or "brand medically necessary"; on electronic prescriptions this is a coded field. In states where substitution is mandatory, the pharmacist must dispense the lower-cost equivalent unless the prescriber or, in some states, the patient asks for the brand.

    Your rights at the pharmacy

    • You can ask which version the pharmacy will dispense and whether a generic is available.
    • In most states you can ask for the brand instead, though you may pay the difference, and your plan may charge a higher copay.
    • Many states require the pharmacist to tell you about a substitution or show it on the label.
    • If your prescriber requires the brand, ask why; for most medicines an AB-rated generic is a safe, lower-cost choice.

    Biosimilars and narrow therapeutic index drugs

    Biologic medicines, such as insulins and adalimumab, have biosimilars rather than generics. Only a biosimilar the FDA has designated interchangeable can be substituted at the pharmacy without the prescriber’s involvement, and most states also require the pharmacist to tell the prescriber afterward. The FDA’s Purple Book lists which biosimilars are interchangeable.

    A few states add rules for narrow therapeutic index drugs, medicines where small differences in blood levels matter, such as some seizure medicines, warfarin and levothyroxine. These can require consent before switching manufacturer or keeping refills on the same product; the state guide notes where they apply.

    Making substitution work for you

    Substitution is one of the simplest ways to pay less, especially just after a generic launches, such as generic Farxiga and generic Januvia in 2026. Cash prices for the same generic still vary between pharmacies; on Script Unlock, licensed pharmacies quote their own price for your prescription.

    Frequently asked questions

    Can a pharmacist switch my brand-name drug to a generic?

    Yes, in every state, if the generic is rated therapeutically equivalent and your prescriber has not indicated the brand is required.

    Do I have to accept the generic?

    In most states you can ask for the brand, though you may pay more. In states with mandatory substitution, the pharmacist must offer the lower-cost equivalent unless the brand is requested or required.

    What does "dispense as written" mean?

    It is how a prescriber tells the pharmacy not to substitute. The exact wording or checkbox is set by state law.

    Can a pharmacist substitute a biosimilar?

    Only an interchangeable biosimilar, and most states then require the pharmacist to notify the prescriber.

    Why does my generic look different from last time?

    Pharmacies buy from different manufacturers, and each generic can look different. Ask the pharmacist if you are unsure, especially for medicines where some states restrict switching.

    Related

    • Pharmacy rules by state
    • Generic Farxiga
    • Generic Januvia
    • New generics in 2026
    • How to pay less for prescriptions
    • Controlled prescription transfers

    Sources

    • FDA Orange Book, therapeutic equivalence evaluations
    • FDA Purple Book, biosimilar and interchangeable products
    • FDA, generic drug facts
    • Each state’s guide, linked in the table, lists that state’s pharmacy law and sources.
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