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Arquel (meclofenamic acid) withdrawal and detection times for horses

Arquel (meclofenamic acid) is an NSAID, also sold as Arquel, Meclofenamate. Below: how 9 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: Restricted: dose and time limitsFEI: Controlled MedicationHISA: Controlled medicationnamed in the rules of 4 state racing commissions

Published detection times for Arquel

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
IFHA / EHSLC
Undated PDF p. 2
4mg/kg for 5 days, once daily · oralDynoton Biove Laboratory, Arques, France6120 h (5 days)
urine

How each rulebook lists Arquel

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. 10 · 2026 (last revised 1 Dec 2025; amendments effective 27 Jul 2026, published 10 Aug 2026)
Restricted: dose and time limits
  • Listed as: Restricted Medication Dose and Time Recommendations · Maximum dose: 0.5 mg/Lb (500 mg/1000Lb) each 12 hours · Screening limit: 2.5 micrograms per milliliter in plasma · Routes: oral
“Meclofenamic acid Arquel® 0.5 mg/Lb (500 mg/1000Lb) Oral, 2 doses each day, 12 hours apart NSAID” — source p. 10

FEI

2026 Equine Prohibited Substances List p. 22 · 2026 (effective 1 January 2026)
Controlled medication
  • Listed as: Controlled Medication
“CONTROLLED Meclofenamic acid Non-steroidal anti-inflammatory” — source p. 22

From 2027-01-01: 2027 Equine Prohibited Substances List p. 23 lists it as Controlled Medication.

AQHA

Restricted: dose and time limits
  • Listed as: Quantitatively Restricted Therapeutic Medication (VIO405) · Maximum dose: 0.5 gram per 12 hours for a 1,000 pound animal; not more than five successive days · Screening limit: 2.5 micrograms per milliliter in plasma
“concentration of Meclofenamic Acid (Arquel®) is 2.5 micrograms per milliliter.” — source p. 47

APHA

Restricted: dose and time limits
  • Listed as: Permitted Therapeutic Substance (SC-085.A) · Maximum dose: 0.5 gram per 12 hours for a 1,000 pound animal; not more than five successive days
“4. Meclofenamic Acid (a NSAID)” — source p. 78

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
“Meclofenamic Acid ... Conditionally Permitted ... Conditionally permitted substances require a 24-hour withdrawal prior to the horse competing.” — source

NCHA

2026 NCHA Rule Book - Standing Rule 35A, Medication and Drug Rules and Guidelines p. 9 · 2026 Rule Book, SR 35A extract (pages 75-95; PDF created 30 Jun 2026)
Restricted: dose and time limits
  • Listed as: Permitted Medication (35A.7) · Maximum dose: "the maximum 12‐hour dose is 0.5 gram" for a 1,000-pound horse; not more than five consecutive days · Screening limit: 2.5 micrograms per milliliter in plasma
“e. Meclofenamic Acid (an NSAID) ... Acid is 2.5 micrograms per milliliter.” — source p. 9

HISA / HIWU

HISA Prohibited Substances List: Controlled Medications p. 19 · Last updated on December 8th, 2023
Controlled medication
  • Listed as: S7 Controlled Medication Substances
“Meclofenamic acid ... NSAID” — source p. 19

ARCI

Controlled medication
  • Listed as: Class 4, Penalty C
“Meclofenamic acid Arquel 4 C” — source p. 36

IFHA / EHSLC

Controlled medication
  • Listed as: Legitimate therapeutic substance controlled by International Screening Limit · Dose in the rule: 2.2mg/kg, single dose · Routes: IV
  • Listed as: Legitimate therapeutic substance controlled by International Screening Limit · Detection time: 120 h (5 days) for 4mg/kg for 5 days, once daily · Routes: oral
“Meclofenamic acid Not commercially available. Sigma † 2.2mg/kg, single dose i.v. (6) ≤48 ^” — source p. 2

State racing commissions

Arquel is named in the medication rules, threshold schedules or withdrawal guidance of 4 state racing commissions: Idaho, Kentucky, New York, Washington. 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 Arquel 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 Arquel

Is Arquel allowed at USEF shows?

The 2026 USEF Guidelines & Rules for Drugs and Medications (with 27 Jul 2026 Guidelines Update) list Arquel as "Restricted Medication Dose and Time Recommendations". Maximum dose: 0.5 mg/Lb (500 mg/1000Lb) each 12 hours. Screening limit 2.5 micrograms per milliliter in plasma. (Page 10.)

What is the FEI detection time for Arquel?

On the 2026 FEI Equine Prohibited Substances List Arquel is a Controlled Medication. The FEI states that a detection time is not a withdrawal time; the treating veterinarian adds a safety margin.

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

No. It is the approximate time Arquel 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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