Naproxen,
Equiproxen, Naprosyn, Alieve

Medication Facts

Performance enhancing: No
Total hours to clear: 72
Frequently used: N/A
ESC ID: NAPROX-0612
Trade names: Alieve
Drug type: NSAID
Plasma half-life · hours: 14
Equine dosing: 10 mg/kg of body weight (approx. 4.55 mg/lb). 1000# horse would get 20-25 tablets 225 mg each
Cmax · peak plasma concentration: 44.2 μg/mL
Tmax · time to peak plasma concentration: 2.5 to 3 hours
ESC concentration guidance: 10 μg/mL and 15 μg/mL.
Primary withdrawal · hours: 12
Washout withdrawal · hours: 0
ESC control type: B1 - Strictly Controlled - Conditionally PE
Medication report required: MED REPORT REQUIRED

Uses & side effects

Product-specific side effects await source review.

Drug interactions

Using more than one NSAID concurrently (e.g., combining phenylbutazone, flunixin meglumine, or firocoxib) drastically increases risks of toxicity without increasing pain relief.Corticosteroids (e.g., Dexamethasone): Combining NSAIDs with steroids increases the likelihood of gastric ulcers and severe GI toxicity.Nephrotoxic Agents: Avoid combining NSAIDs with aminoglycoside antibiotics (e.g., gentamicin) or diuretics, as this significantly increases the risk of acute renal failure.Blood Thinners: Concomitant use with anticoagulants (e.g., heparin) increases the risk of bleeding complications.Dehydration/Pre-existing Disease: NSAIDs are more toxic when horses are dehydrated, septic, or have pre-existing kidney or hepatic disease

Contraindications

Veterinary guidance

Dosing and pharmacokinetic data are sourced from publicly available resources, and accuracy is not guaranteed. The dosing samples provided are for illustrative purposes only and should not be used for actual administration; they assume a single medication is delivered at the correct individual dose. Loading doses, or combinations with other substances to increase efficacy or mask concentration levels, are strictly prohibited. Veterinarians must prescribe all medications and determine appropriate withdrawal times based on the horse's health, administration route, drug strength, and timing. The health of the horse must always take priority over performance.

Medication combinations

Combining certain substances or use of can trigger dangerous interactions or contraindications, posing severe health risks or creating unintended performance-enhancing effects. If a medical treatment causes these interactions or alters performance, the horse must be withdrawn from competition until its system clears, or face an adverse drug test.

Sanctioning-body comparison

Plasma only. Compare published competition guidance for this medication. ESC guidance remains in Medication Facts above. A dosing guideline, withdrawal recommendation and laboratory detection threshold are different measures.

Sources reviewed September 23, 2026. “Not verified” means a gap in this comparison, not zero tolerance or permission. Doses describe the cited rules; your veterinarian must determine treatment and withdrawal.

Published guidance by organization
Organization	Published dose & route	Plasma concentration	Withdrawal / timing	Control / penalty class
AQHA Show HorsesShow rules · 2026 handbook Conditions & sources One permitted NSAID at a time. Flunixin emergency exception requires veterinary examination, reporting and 24 h out of competition. Guidelines do not guarantee a compliant result. VIO404–406; VIO405.6 Reviewed 2026-09-23 2026 AQHA Handbook · VIO400–406 Current AQHA rulebook	4 mg/lb per 24 h orally (4 g/1,000 lb); up to 5 days.	40.0 µg/mL	12 h	Quantitatively restricted therapeutic NSAID.
APHA Paint Show HorsesShow rules · 2026 Rule Book Conditions & sources APHA’s published dosing guidance is not a numerical plasma allowance. Government restrictions and all SC-085 conditions still apply. SC-085.A.5 Reviewed 2026-09-23 2026 APHA Rule Book · SC-085, pp. 75–80 Current APHA rulebook	4 mg/lb per 24 h orally (4 g/1,000 lb); up to 5 days.	No numeric plasma limit stated in SC-085.A.	No drug-specific precompetition stop time stated in SC-085.A.	Listed permitted therapeutic substance.
ARCI Model RulesRacing model · Rules 15 / UCG 20.0 / CTMS 4.2.1 Conditions & sources An unverified entry is not permission to use this medication. Consult the linked current rules. ARCI model comparison only; no state-specific rule is substituted. Schedule timing is tied to its stated regimen and is not a clearance guarantee. UCG 20.0 PDF p. 41 Reviewed 2026-09-23 ARCI UCG 20.0 · April 2026 ARCI CTMS 4.2.1 · December 2020 ARCI Model Rules 15 · August 2026	Not verified for this medication.	Not verified for this medication.	Not verified for this medication.	Drug Class 4 · Penalty Class C. No dosing permission is implied by classification.
USEFNational Therapeutic Substance Provisions · 2026 + July amendment Conditions & sources Therapeutic Substance Provisions only. One permitted NSAID at a time; additional permitted NSAIDs need the source’s 3-day interval. Emergency exceptions and other restrictions apply. Guidelines do not guarantee clearance. GR410.4; NSAID guidelines Reviewed 2026-09-23 2026 USEF Drugs & Medications Guidelines · August 10 update USEF July 27, 2026 update	4 mg/lb per 24 h orally (4 g/1,000 lb); up to 5 days.	40.0 µg/mL	12 h	Restricted therapeutic NSAID under GR410.

Naproxen,Equiproxen, Naprosyn, Alieve

Uses & side effects

Drug interactions

Contraindications

Sanctioning-body comparison

Naproxen,
Equiproxen, Naprosyn, Alieve