StallWise / ShowSafe Pro / Withdrawal times / Rompun (xylazine)

Rompun (xylazine) withdrawal and detection times for horses

Rompun (xylazine) is a sedative, also sold as Rompun, Anased, Xylazine Hydrochloride. Below: how 7 show and racing governing bodies list it, every published detection time for the dose and route studied, and the document and page each value comes from.USEF: Permitted with conditionsFEI: Controlled Medication, detection time 72 h (3 days)HISA/HIWU: detection time 72 h (3 days)named in the rules of 20 state racing commissions

Published detection times for Rompun

Each row is one study the governing body published: its own dose, route and formulation. A different dose or route was not studied, and the body says so.

Body and documentDose and route studiedFormulationHorsesDetection time
USEF (US Equestrian)
2026 (last revised 1 Dec 2025; amendments effect… p. 11
dose not stated in the row168 h (7 days)
plasma / urine
FEI
2024 (16 December 2024) p. 2
0.4mg/kg, single dose · IVChanazine®672 h (3 days)
Equestrian Canada
Rev. January 15, 2025 p. 18
500mg IV · IV24 h (1 day)
HISA / HIWU
Last updated on December 8th, 2023 p. 30
200 mg single IV dose · IV72 h (3 days)
plasma / urine
HISA / HIWU
080624 p. 4
200 mg single IV dose · IV72 h (3 days)
plasma / urine
IFHA / EHSLC
Undated PDF p. 3
0.4mg/kg, single dose · IVChanazine®672 h (3 days)
urine
RMTC (advisory)
Updated September 30, 2024 p. 4
200 mg single IV dose · IV672 h (3 days)

Advisory withdrawal guidance (RMTC)

The Racing Medication and Testing Consortium publishes withdrawal guidance built on HISA's detection times. It is advisory, not a rule, and ShowSafe Pro shows it beside the HISA result, never in place of it.

Dose and routeWithdrawal guidanceHISA detection timeSource
200 mg single IV dose · IV96 h (4 days)RMTC advisory p. 4

How each rulebook lists Rompun

Transcribed from the governing bodies' own documents. Each entry links to the document and quotes the row it came from.

USEF (US Equestrian)

2026 USEF Guidelines & Rules for Drugs and Medications (with 27 Jul 2026 Guidelines Update) p. 9 · 2026 (last revised 1 Dec 2025; amendments effective 27 Jul 2026, published 10 Aug 2026)
Permitted with conditions
  • Listed as: Potentially Permitted with Medication Report Form (MRF) according to GR411 · Timing: not within 24 h (1 day) of competition · Medication report form: required
  • Listed as: How Long Drugs Remain Detectable · Detection time: 168 h (7 days) for the dose studied · Medication report form: required
“Potentially Permitted with Medication Report Form (MRF) according to GR411: ... xylazine (Rompun®, AnaSed®)” — source p. 9

FEI

2026 Equine Prohibited Substances List p. 37 · 2026 (effective 1 January 2026)
Controlled medication
  • Listed as: Controlled Medication
“CONTROLLED Xylazine Sedative” — source p. 37
FEI List of Detection Times p. 2 · 2024 (16 December 2024)
Controlled medication
  • Listed as: Controlled Medication · Detection time: 72 h (3 days) for 0.4mg/kg, single dose · Routes: IV
“XYLAZINE2 Chanazine® 0.4mg/kg, single i.v. 6 72 (3d) dose” — source p. 2

From 2027-01-01: 2027 Equine Prohibited Substances List p. 38 lists it as Controlled Medication.

Equestrian Canada

Controlled medication
  • Listed as: Prohibited substance
  • Listed as: Prohibited substance · Detection time: 24 h (1 day) for 500mg IV · Routes: IV
“Xylazine” — source p. 11

NRHA

NRHA Medications Database · Database reflecting Board-approved changes effective 1 Jan 2026 (retrieved 3 Oct 2026)
Permitted with conditions
  • Listed as: Conditionally Permitted · Timing: not within 24 h (1 day) of competition · Medication report form: required
“Xylazine ... Conditionally Permitted ... Conditionally permitted substances require a 24-hour withdrawal prior to the horse competing.” — source

HISA / HIWU

Controlled medication
  • Listed as: Controlled Medication Substance · Screening limit: 10 ng/mL in urine (as 4-hydroyxylazine) or 0.05 ng/mL in serum or plasma · Detection time: 72 h (3 days) for 200 mg single IV dose · Routes: IV
“Xylazine ... 200 mg single IV dose ... 72 hours ... 10 ng/mL in urine (as 4-hydroyxylazine) or 0.05 ng/mL in serum or plasma” — source p. 4
HISA Prohibited Substances List: Controlled Medications p. 30 · Last updated on December 8th, 2023
Controlled medication
  • Listed as: S7 Controlled Medication Substances · Screening limit: 10 ng/mL in urine (as 4-OH xylazine); 0.05 ng/mL in serum or plasma · Detection time: 72 h (3 days) for 200 mg single IV dose · Routes: IV
“Xylazine ... 72 hours: 200 mg single IV dose. ... 10 ng/mL in urine (as 4-OH xylazine); 0.05 ng/ mL in serum” — source p. 30

ARCI

Controlled medication
  • Listed as: Class 3, Penalty B
“Xylazine Rompun, Bay Va 1470 3 B” — source p. 56
ARCI Controlled Therapeutic Medication Schedule for Horses p. 6 · Version 4.2.1 (Revised December 2020); policies from Model Rules Version 15 (August 2026)
Permitted up to a threshold
  • Listed as: Controlled Therapeutic Medication · Dose in the rule: 200 milligrams intravenously · Screening limit: 200 picograms per milliliter of plasma or / serum · Routes: IV
“Xylazine | 200 picograms per milliliter of plasma or serum | 48 hours” — source p. 6

IFHA / EHSLC

Controlled medication
  • Listed as: Legitimate therapeutic substance controlled by International Screening Limit · Detection time: 72 h (3 days) for 0.4mg/kg, single dose · Routes: IV
“Xylazine Chanazine® 0.4mg/kg, single dose i.v. (6) 72” — source p. 3

State racing commissions

Rompun is named in the medication rules, threshold schedules or withdrawal guidance of 20 state racing commissions: Arizona, California, Colorado, Florida, Illinois, Indiana, Kentucky, Louisiana, Maine, Maryland, Minnesota, Nebraska, New York, Ohio, Oklahoma, Oregon, Pennsylvania, Texas, Washington, West Virginia. Most states publish thresholds (concentrations), not times, and several adopt the ARCI schedule by reference. ShowSafe Pro Racing layers each state's rules over HISA or ARCI the way that state applies them, for all 32 states with live pari-mutuel racing.

Detection time is not withdrawal time

A published detection time tells you how long Rompun stayed detectable in a handful of horses given one dose by one route. It does not tell you when your horse is clear: a bigger dose, a different route, repeated doses, a joint injection or a slower horse all push the real figure out, and every governing body says to add a safety margin set by your veterinarian. Here is how to read the rulebook.

ShowSafe Pro takes the doses already logged for your horse, matches each one to the published row for that dose and route, adds the margin your vet set, and flags anything the studies never covered as Unknown, ask your vet instead of guessing. Every answer shows the document, page and line it came from, for every rulebook the show runs under.

A detection time is the approximate period a drug or its metabolite stayed detectable in the horses studied, at the dose and route studied. It is not a withdrawal time. No governing body publishes withdrawal times for you; your veterinarian sets the safety margin for your horse. Nothing on this page is a veterinary ruling or a promise that a horse will test clean. Rules change; the document, version and page behind every value are linked so you can check the current text.

Questions about Rompun

Is Rompun allowed at USEF shows?

The 2026 USEF Guidelines & Rules for Drugs and Medications (with 27 Jul 2026 Guidelines Update) list Rompun as "Potentially Permitted with Medication Report Form (MRF) according to GR411". Not within 24 h (1 day) of competition. (Page 9.)

What is the FEI detection time for Rompun?

The FEI List of Detection Times gives 72 h (3 days) for 0.4mg/kg, single dose IV (Chanazine®). On the 2026 FEI Equine Prohibited Substances List Rompun is a Controlled Medication. The FEI states that a detection time is not a withdrawal time; the treating veterinarian adds a safety margin.

How long before a race can a horse have Rompun under HISA?

HIWU's published detection time for Rompun is 72 h (3 days) for 200 mg single IV dose, screening limit 10 ng/mL in urine (as 4-OH xylazine); 0.05 ng/mL in serum or plasma. RMTC's advisory withdrawal guidance for the same dose is 96 h (4 days). A detection time is not a withdrawal time; HISA leaves the safety margin to your veterinarian.

Does a published detection time mean my horse will test clean?

No. It is the approximate time Rompun stayed detectable in the horses studied, at that dose and route. Your horse, dose, route and number of doses may differ. Every governing body tells you to add a safety margin set by your veterinarian, and none publishes a withdrawal time. ShowSafe Pro applies the published row for the dose and route you actually gave, adds your vet's margin, and says 'Unknown' when the studies do not cover what you gave.

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