Equine Sports Council

Controlled Medications Library

ESC MEDICATION CLASSIFICATIONClass A - Therapeutic

ESC Medication Library · Revision 2

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Medication Facts

Performance enhancing
No
Total hours to clear
Not recorded
Frequently used
N/A
ESC ID
ANISOT-0076
Trade names
Not recorded
Drug type
Anticholinergic
Plasma half-life · hours
Not Published
Equine dosing
Consult Veternarian
Cmax · peak plasma concentration
Unavailable
Tmax · time to peak plasma concentration
Unavailable
ESC concentration guidance
May not exceed 6% of efficacy in plasma
Primary withdrawal · hours
12
Washout withdrawal · hours
0
ESC control type
A1 - Generally Controlled - Therapeutic
Medication report required
Generally not required, however understand exceptions.

Uses & side effects

Product-specific side effects await source review.

Drug interactions

anticholinergic drugs in horses are used primarily to reduce smooth muscle spasms, decrease secretions, dilate the pupils, and modify gastrointestinal or respiratory activity. They work by blocking acetylcholine at muscarinic receptors.

Common equine anticholinergic drugs include:

Atropine
Scopolamine (hyoscine)
Glycopyrrolate
N-butylscopolammonium bromide
Common Uses in Horses
Gastrointestinal spasms / colic

The most common use is:

treatment of spasmodic colic
reducing intestinal cramping
rectal relaxation during examination

N-butylscopolammonium bromide is widely used for:

spasmodic colic
intestinal hypermotility
facilitating rectal exams
Ophthalmic use

Atropine is commonly used:

to dilate the pupil
relieve painful eye spasms in uveitis (“moon blindness”)
prevent ocular adhesions
Anesthesia and respiratory management

Glycopyrrolate or atropine may be used:

to reduce salivation and airway secretions
to prevent vagal bradycardia during anesthesia

Contraindications

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
OrganizationPublished dose & routePlasma concentrationWithdrawal / timingControl / penalty class
AQHA Show HorsesShow rules · 2026 handbook
Conditions & sources

An unverified entry is not permission to use this medication. Consult the linked current rules.

Reviewed 2026-09-23

Not verified for this medication.Not verified for this medication.Not verified for this medication.Medication-specific control not yet verified.
APHA Paint Show HorsesShow rules · 2026 Rule Book
Conditions & sources

An unverified entry is not permission to use this medication. Consult the linked current rules.

Reviewed 2026-09-23

Not verified for this medication.Not verified for this medication.Not verified for this medication.Medication-specific control not yet verified.
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. 14

Reviewed 2026-09-23

Not verified for this medication.Not verified for this medication.Not verified for this medication.Drug Class 4 · Penalty Class B. No dosing permission is implied by classification.
USEFNational Therapeutic Substance Provisions · 2026 + July amendment
Conditions & sources

An unverified entry is not permission to use this medication. Consult the linked current rules.

Reviewed 2026-09-23

Not verified for this medication.Not verified for this medication.Not verified for this medication.Medication-specific control not yet verified.