Medication approval journey

hydroxyzine (Vistaril)

Approved for Anxiety and tension associated with psychoneurosis

FDA approvedOther anti-anxiety medicationTaper risk: low

Before changing anything

Low risk from stopping, but still worth planning

Withdrawal risk in this group is generally low, but dose changes are still worth discussing rather than improvising.

How long the trials actually ran

We could not establish a longest trial length for hydroxyzine. That is a gap in what we can show you — not evidence that the trials ran long.

Approved before the Physician Labeling Rule, so no clinical studies section was ever required. The absence is the state of the public record, not a gap in our research.

The gap between how long the trials ran and how long people actually take these medications is the single most important thing on this page. It is not evidence that longer use is unsafe or ineffective. It is evidence that longer use was not what got tested.

How many Americans take hydroxyzine

Survey-based federal estimates, published with a lag of about two years. They count prescriptions filled, not outcomes.

14,857,240
prescriptions in the United States (2024)
4,680,154
people filling them (2024)

Prescriptions are up 90% since 2014. Whatever you decide about hydroxyzine, you are deciding alongside about 4,680,154 other people this year.

Source: ClinCalc DrugStats (Medical Expenditure Panel Survey (MEPS), Agency for Healthcare Research and Quality), CC BY-SA 4.0, release 2026.08.

What people report to the FDA about hydroxyzine

Read this before the numbers.

Anyone can file an adverse event report — patients, doctors, manufacturers — and nobody verifies that the drug caused what was reported. There is no denominator: tens of millions of prescriptions generate reports at an unknowable rate, and reporting rises with news coverage, not necessarily with harm. Counts below are report volumes, not rates, and cannot be compared between drugs. The FDA itself says not to use this data to make medical decisions — we show it because you deserve to see what is in the public record, with its limits stated plainly.

50,845
reports mentioning hydroxyzine, all time
33,218
filed as serious (a report-level flag covering every drug and outcome in the report)

Most-reported reactions

  • Drug ineffective3,485
  • Pruritus3,383
  • Nausea3,067
  • Fatigue2,961
  • Off label use2,620
  • Toxicity to various agents2,567
  • Completed suicide2,544
  • Pain2,510
  • Headache2,453
  • Rash2,274

“Drug ineffective” ranking this high is worth noticing: a report of not being helped counts as an adverse event too, and people file them in large numbers.

Source: FDA Adverse Event Reporting System (FAERS), via openFDA, data through 2026-07-30.

Who pays for hydroxyzine

Two claims datasets and one survey, covering different populations with different instruments — they cannot be reconciled by arithmetic, and where their sum crowds the all-payer estimate, that is a finding about the estimates rather than a percentage.

Medicare Part D · claims · 2024Medicaid · claims floor · 2024All-payer · survey · 2024Commercially insured adults · not publishedChildren · no per-drug data
Medicare Part D
Read the under-65 group correctly before the numbers: Medicare before 65 means the disabled and dual-eligible population — among the sickest, highest-need people in the program — and reading their utilization as typical adult use would be a category error. The beneficiary total sums brand-level rows, so treat it as an upper bound on distinct people. 1,889,798 beneficiaries filled 6,278,612 claims in 2024 — 1,218,334 aged 65 and over, and 671,464 under 65.
Medicaid
At least 8,616,838 prescriptions in 2024 — a floor, because 187 of 977 national data rows are suppressed for privacy and contribute zero. Medicaid covers more children than any insurer in the country and publishes no age split — how much of this number is pediatric use is not knowable from public data.
All payers (survey estimate)
The MEPS-based estimate above puts the whole country at 14,857,240 prescriptions and 4,680,154 people in 2024. Subtracting the public programs from it would produce a number for everyone else — and we do not print that number, because subtracting a survey from claims counts manufactures precision that does not exist.
The population nobody counts
The commercially insured working-age adult — statistically, the likeliest person to be reading this page — is the one population with no public per-drug count anywhere. Private claims data exists and is sold, but nothing a patient can check is published. For children the record is thinner still: no public source counts pediatric use of hydroxyzine specifically; the closest the public record comes is condition-level treatment rates for children, which we have traced for one condition in how childhood ADHD got counted.

Sources: Medicare Part D Prescribers — by Geography and Drug, data.cms.gov, National rows, data year 2024 (published with ~17-month lag). Medicaid State Drug Utilization Data 2024, data.medicaid.gov, national aggregate rows. Retrieved 2026-09-01.

The approval, step by step

  1. Step 1

    What the approval was actually based on

    Which studies did the FDA rely on, how long did they run, and who was in them?

    read the label on DailyMed

    Our reading

    Approved in 1956, forty-five years before any rule required a label to print its trials, and with four submissions filed against the application in seventy years. There is no clinical studies section because none was ever required to exist. That is the state of the public record and not a gap in our research. Hydroxyzine is an antihistamine that is sedating, and it is prescribed for anxiety largely because it is not addictive and can be taken as needed — the same shape of argument as buspirone, made about a drug that predates modern trial standards entirely.

  2. Step 2

    The approval

    When was it approved, under what application, and by whose review?

    Approved
    May 31, 1956
    Application
    NDA010485
    Review
    STANDARD
    Holds it now
    Roerig (Pfizer)
    Label submissions since
    4

    Drug applications are bought and sold. The company that holds this one today is often not the company that ran the trials, and where we cannot state the original sponsor from a source we leave it blank rather than guess.

    Source: openFDA Drugs@FDA, original application ORIG-1

  3. Step 3

    What was added after it was on the market

    Which warnings arrived only after millions of people were already taking it?

  4. Step 4

    What independent research has found since

    What has been learned by people who were not selling it?

  5. Step 5

    What still is not known

    Which questions you might reasonably have has nobody answered yet?

    • Approved eight years before the FDA was required to see efficacy evidence at all. What is this prescription actually resting on?
    • The indication is "anxiety and tension associated with psychoneurosis" — language from 1956. It has not been restated in modern diagnostic terms because the label has barely been touched.
    • It is chosen over a benzodiazepine because it is not habit-forming. Compared on effect rather than on risk, what is known?

Deciding about hydroxyzine?

Open hydroxyzine (Vistaril) in Resolv

The app has the full approval journey, the resources behind it, and people working through the same questions.

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