Xanax (alprazolam) vs Klonopin (clonazepam)
Xanax and Klonopin, compared on what the public record actually supports: side effects by rate from each FDA label, what the largest trial comparison found, who takes each one, who pays, what the labels warn, and what the litigation record holds. Sources on every number.
the short answer
- is Xanax or Klonopin more effective? there is no head-to-head trial record in our library that settles this pair, and we do not fill the gap with a guess. what can be compared is below: each label's own side-effect table, who takes each drug, who pays, and the legal record.
- which has fewer side effects? the labels say their trials “cannot be directly compared”, because each drug was tested in different people under different rules. what each label prints: Xanax (alprazolam): the label prints no discontinuation rate in the section we transcribed. Klonopin (clonazepam): 17% stopped for an adverse reaction vs 9% on placebo (Klonopin label, SPL version 6, effective 2025-12-01). the reactions both labels list, side by side, are in the table below.
- which should i take? not a question this page answers. the odds ratios are averages across thousands of strangers; your history, other medications and what you can live with are not in them. the questions for your prescriber below are built from what is on this page.
What this page will not do is rank them. For most same-class pairs, head-to-head efficacy differences are smaller than the rankings look — the largest network meta-analysis ever run (21 antidepressants, 522 trials) found every drug beat placebo and the gaps between drugs mostly modest and uncertain. Which one fits you turns on your history, your other medications, and side-effect trade-offs — a prescriber conversation. This page arms that conversation; here are the questions worth taking into it →
side effects by rate: what each label prints, not a head-to-head trial
the labels' own warning, first: “Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.” the two columns below come from different trials, in different people, under different inclusion rules. read each against its own placebo column, not against the other drug.
| reaction | XANAX (n=1388) vs Placebo (n=1231) | <1 mg (n=96) / 1–<2 mg (n=129) / 2–<3 mg (n=113) / ≥3 mg (n=235) / All Klonopin Groups (N=574) vs Placebo (N=294) |
|---|---|---|
| constipation | 26% vs 15% | 0% / 1% / 5% / 3% / 2% vs 2% |
| somnolence | 77% vs 43% | 26% / 35% / 50% / 36% / 37% vs 10% |
| decreased appetite | 28% vs 24% | 1% / 1% / 0% / 3% / 1% vs 1% |
| libido decreased | 14% vs 8% | 0% / 1% / 3% / 1% / 1% vs 0% |
- Xanax (alprazolam): the label prints no discontinuation rate in the section we transcribed.
- Klonopin (clonazepam): 17% stopped for an adverse reaction vs 9% on placebo (Klonopin label, SPL version 6, effective 2025-12-01).
what makes each table, in the labels' words
- Xanax (alprazolam), SPL effective 2023-01-18, 6 ADVERSE REACTIONS / 6.1 Clinical Trials Experience, immediate-release tablets (Schedule IV controlled substance). inclusion rule: “Table 2: Adverse Reactions Occurring in ≥1% in XANAX-treated Patients and Greater than Placebo-treated Patients in Placebo-Controlled Trials (Up to 10 Weeks) for Panic Disorder” trials: “The data in the two tables below are estimates of adverse reaction incidence among adult patients who participated in: 4-week placebo-controlled clinical studies with XANAX dosages up to 4 mg per day for the acute treatment of generalized anxiety disorder (Table 1); short-term (up to 10 weeks) placebo-controlled clinical studies with XANAX dosages up to 10 mg per day for panic disorder, with or without agoraphobia (Table 2).” DailyMed
- Klonopin (clonazepam), SPL version 6, effective 2025-12-01, ADVERSE REACTIONS (old-format label; panic-disorder subsection), tablets, 0.5 mg / 1 mg / 2 mg (Schedule IV controlled substance). inclusion rule: “Table 3 enumerates the incidence, rounded to the nearest percent, of treatment-emergent adverse events that occurred during acute therapy of panic disorder from a pool of two 6- to 9-week trials. Events reported in 1% or more of patients treated with Klonopin (doses ranging from 0.5 to 4 mg/day) and for which the incidence was greater than that in placebo-treated patients are included.” trials: “The panic-disorder data come from two double-blind, placebo-controlled studies of adult outpatients with a primary diagnosis of panic disorder (DSM-IIIR) with or without agoraphobia: Study 1, a 9-week fixed-dose study (Klonopin 0.5, 1, 2, 3 or 4 mg/day or placebo), and Study 2, a 6-week flexible-dose study (0.5 to 4 mg/day; mean dose during optimal dosing 2.3 mg/day). Label methodology note: "Adverse events during exposure to Klonopin were obtained by spontaneous report and recorded by clinical investigators using terminology of their own choosing… CIGY dictionary terminology has been used to classify reported adverse events… An event was considered treatment-emergent if it occurred for the first time or worsened while receiving therapy following baseline evaluation."” DailyMed
every row above was transcribed from the current FDA label on 2026-09-08; the full tables, including the reactions only one label lists, are on side-effect rates, drug vs placebo. the sexual side-effect rows carry each label's own underreporting caveat on the SSRI sexual side effects page.
alprazolam (Xanax)
benzodiazepine
- FDA approval
- 1981 · full approval journey →
- Who takes it (US, 2024)
- 3,426,968 patients · 12,541,990 prescriptions (AHRQ MEPS)2014 → 2024: 28,897,889 → 12,541,990 prescriptions, down 57%Correction (29 September 2026): An earlier version of this section took its numbers from ClinCalc DrugStats, a third-party site that republishes this survey; we now compute them from AHRQ’s public-use files ourselves.
- Who pays (2024)
- Medicare: 11,707,746 claims · 2,316,589 beneficiariesMedicaid: ≥3,090,918 prescriptionsCommercial claims: not published in any public dataset — a real absence, not a zero.
- Boxed warning
- Yes — on the current FDA label. read it in context →
- Adverse-event reports (FAERS)
- Caveat first: FAERS counts unverified REPORTS, not patients or rates — no denominator, and attention inflates reporting. Never compare these counts head-to-head; a longer-marketed, more-prescribed drug accumulates more reports by exposure alone. how to read FAERS →204,912 all-time reports; most-reported terms: drug ineffective, nausea, fatigue
- Legal & safety record
- no dedicated record page yet; the journey page carries label history
clonazepam (Klonopin)
benzodiazepine
- FDA approval
- 1975 — for seizure disorders; the panic indication came in the 1990s · full approval journey →
- Who takes it (US, 2024)
- 2,154,594 patients · 11,861,003 prescriptions (AHRQ MEPS)2014 → 2024: 21,021,489 → 11,861,003 prescriptions, down 44%Correction (29 September 2026): An earlier version of this section took its numbers from ClinCalc DrugStats, a third-party site that republishes this survey; we now compute them from AHRQ’s public-use files ourselves.
- Who pays (2024)
- Medicare: 8,856,358 claims · 1,315,917 beneficiariesMedicaid: ≥3,836,777 prescriptionsCommercial claims: not published in any public dataset — a real absence, not a zero.
- Boxed warning
- Yes — on the current FDA label. read it in context →
- Adverse-event reports (FAERS)
- Caveat first: FAERS counts unverified REPORTS, not patients or rates — no denominator, and attention inflates reporting. Never compare these counts head-to-head; a longer-marketed, more-prescribed drug accumulates more reports by exposure alone. how to read FAERS →159,283 all-time reports; most-reported terms: drug ineffective, fatigue, nausea
- Legal & safety record
- no dedicated record page yet; the journey page carries label history
questions for your prescriber, built from this page
this page does not tell you to start, stop or switch anything. it arms the conversation where that decision belongs. take these in:
- which of Xanax and Klonopin did you have in mind first, and what in my history points that way?
- the trials put these two close together on average. what, for me specifically, breaks the tie: another medication i take, a side effect i can't live with, sleep, weight, sexual function?
- the label lists these reactions above placebo for the one you're suggesting. which of them should i expect in the first weeks, and which would make you want to hear from me the same day?
- how long were the approval trials, and what do we know past that point?
- how will we judge whether it is working, by when, and what is the plan if it isn't?
- if i ever want to come off it, how is that done, and over how long?
- is there a cheaper generic or a formulation that changes the dosing, and does my insurance prefer one of these two?
the longer checklist, for any antidepressant, is questions to ask before starting antidepressants. if you are already on one and it feels like it stopped working, that has its own page.
What the warnings mean, drug by drug
Each explainer reads one drug's current FDA label and the studies in our library, in both directions: the boxed warnings with the label's own numbers, the trials behind the approval and how long they ran, side effects by rate, and the research since.
Questions people search
Is Xanax or Klonopin better?
No honest page can answer that in one line. Head-to-head differences between comparable psychiatric medications are usually smaller than rankings suggest, and which fits you depends on your history, other medications, and side-effect trade-offs, a prescriber conversation. What can be compared is the public record (usage, payers, label warnings, approval history, litigation), which is what this page does, with sources.
Is Xanax the same as alprazolam, and Klonopin the same as clonazepam?
Xanax is a brand name for alprazolam. Klonopin is a brand name for clonazepam. alprazolam is a benzodiazepine; clonazepam is a benzodiazepine. This page uses the generic names because the federal datasets do.
Which has fewer side effects, Xanax or Klonopin?
The two FDA labels cannot be compared head to head, in their own words, because each drug's trials ran in different people under different rules. What each label prints: Xanax (alprazolam): the label prints no discontinuation rate in the section we transcribed. Klonopin (clonazepam): 17% stopped for an adverse reaction vs 9% on placebo (Klonopin label, SPL version 6, effective 2025-12-01). The page shows the reactions both labels list, each against its own placebo column.
Which is prescribed more, Xanax or Klonopin?
The page shows federal survey estimates we compute from AHRQ’s Medical Expenditure Panel Survey public-use files for both alprazolam and clonazepam: patients and prescriptions in the latest reliable year, and the yearly series from 2014 where AHRQ’s reliability rule allows it, with a direction stated only when the change is larger than the survey’s margin of error. Prescription volume reflects habits, prices, and marketing as much as evidence, so it is context, not a verdict.
Where these numbers come from
- Patients and prescriptions: computed by us from AHRQ's public-use Medical Expenditure Panel Survey Prescribed Medicines files, 2014 (HC-168A) to 2024 (HC-254A), with AHRQ's reliability rule (a year with fewer than 60 respondents or a relative standard error over 50% is not shown) — counts of people filling prescriptions, not outcomes. A direction is stated only when the change is larger than the survey's margin of error. Until 29 September 2026 these came from ClinCalc DrugStats, a third-party site; see the correction under each drug where a figure changed.
- Medicare/Medicaid: CMS public datasets; commercial insurance publishes no per-drug series, so it renders as an absence, never a synthesized number.
- Label facts: the drugs' current FDA labels via DailyMed — quoted in context on each drug's approval-journey page.
- FAERS: openFDA — reports, never rates; the caveat travels above every count.
- Litigation: court records and regulator documents only, on the linked record pages; settled is never adjudicated.
Explore both drugs in depth: /m/alprazolam · /m/clonazepam · or the whole library →