gabapentin (Neurontin)

How long the trials actually ran

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

The label carries a clinical studies section describing the trials the approval rested on.

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 gabapentin

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

46,839,967

prescriptions in the United States (2024)

11,472,603

people filling them (2024)

Prescriptions are up 19% since 2014. Whatever you decide about gabapentin, you are deciding alongside about 11,472,603 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 gabapentin

361,481

reports mentioning gabapentin, all time

229,940

filed as serious (a report-level flag covering every drug and outcome in the report)

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

Known interactions, from the label

The FDA label’s interactions section, verbatim. A pharmacist checking your actual medication list beats any published list — including this one.

FDA label for gabapentin, effective August 27, 2026 — DailyMed.

Who pays for gabapentin

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

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. 7,966,024 beneficiaries filled 36,824,304 claims in 2024 — 6,600,966 aged 65 and over, and 1,365,058 under 65.

Medicaid

At least 12,411,432 prescriptions in 2024 — a floor, because 420 of 2,285 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 46,839,967 prescriptions and 11,472,603 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 gabapentin 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?

   NEURONTIN was evaluated for the management of postherpetic neuralgia (PHN) in two randomized, double-blind, placebo-controlled, multicenter studies. The intent-to-treat (ITT) population consisted of a total of 563 patients with pain for more than 3 months after healing of the herpes zoster skin rash (Table 6).

   FDA-approved labelling, 14 CLINICAL STUDIES 14.1 Postherpetic Neuralgia — read the label on DailyMed

   Our reading

   Read the indication, not the quote. Gabapentin is approved for nerve pain after shingles and as an add-on for epilepsy. It is not approved for anxiety, for bipolar disorder, for sleep, for alcohol withdrawal or for anything else psychiatric — and it is prescribed for all of them, constantly. There is no approval-grade evidence for any of those uses because no such application was ever made. In 2004 Parke-Davis's parent pleaded guilty and paid $430 million over the illegal promotion of gabapentin for exactly these off-label psychiatric uses. That is not an argument that it cannot help you. It is the reason you should ask what the recommendation is based on.

2. Step 2

   The approval

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

   Approved

   December 30, 1993

   Application

   NDA020235

   Review

   PRIORITY

   Original sponsor

   Parke-Davis (now Viatris)

   Holds it now

   Viatris

   Label submissions since

   38

   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?

   • Gabapentin and pregabalin can suppress breathing, and that is not a boxed warning

     26 years after approval

     In December 2019 the FDA warned that gabapentin and pregabalin can cause serious and potentially fatal respiratory depression. The risk concentrates in people with specific risk factors: taking opioids or other central nervous system depressants at the same time, existing respiratory impairment such as COPD, and older age.

     Being precise about what the FDA actually did, because this gets misreported constantly: it required new Warnings and Precautions labelling, not a boxed warning. The current Neurontin label has no boxed warning at all. Anyone telling you gabapentin carries a black-box warning for breathing problems is wrong, and getting it wrong makes the real warning easier to dismiss.

     The FDA also required manufacturers to run trials on abuse potential, particularly combined with opioids.

     Worth asking

     Does anything else I take count as a CNS depressant, and given my lungs and my age, what is the lowest dose that would work for me.

     Neurontin, Gralise, Horizant (gabapentin) and Lyrica, Lyrica CR (pregabalin): Drug Safety Communication — Serious Breathing Problems — U.S. Food and Drug Administration (2019)

4. Step 4

   What independent research has found since

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

   • Withdrawal from these medications can take months, and NICE says so

     29 years after approval

     NICE guideline NG215 covers safe prescribing and managed withdrawal for five groups of medication: opioids, benzodiazepines, gabapentinoids, Z-drugs and antidepressants. It is the closest thing there is to an official answer on how coming off actually goes.

     It states that withdrawal can be difficult and may take several months or more, that symptoms vary widely in type and severity, that they affect both physical and mental health, and that they can be delayed in onset and can persist. Two recommendations are worth quoting to a prescriber. Do not stop a medicine abruptly except in exceptional medical circumstances. And taper using a slow, stepwise reduction proportionate to the current dose, so the decrements get smaller as the dose gets lower — not a fixed cut each time.

     That last detail is the one most commonly missed. Gabapentinoids are the exception in the guideline and are reduced by a fixed amount at each step.

     Worth asking

     Can we write the taper down, what size are the steps near the end, and how long do I hold at each step before the next reduction.

     Medicines associated with dependence or withdrawal symptoms: safe prescribing and withdrawal management for adults (NG215) — National Institute for Health and Care Excellence (2022)

5. Step 5

   What still is not known

   Which questions you might reasonably have has nobody answered yet?

   • If you were prescribed gabapentin for anxiety, sleep or mood, that use is not on the label and has no registration trial behind it.
   • The off-label psychiatric market for this drug was built by a marketing campaign that resulted in a criminal conviction. Where did your prescriber's confidence come from?
   • It is increasingly recognised as having withdrawal effects and misuse potential, neither of which was part of the 1993 approval.