# Hyoscine Butylbromide (N-Butylscopolammonium): veterinary dose and monograph

> Hyoscine Butylbromide (N-Butylscopolammonium) is a veterinary gastrointestinal drug. Quaternary antimuscarinic spasmolytic for spasmodic/gas colic, simple impactions and oesophageal choke in horses, and as a short-acting bronchodilator. Indications include spasmodic / flatulent colic and simple impactions (horses); oesophageal obstruction (choke) — with oxytocin in geldings/stallions; bronchospasm relief (diagnostic/short-term). This monograph lists 2 reference doses for horses, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/butylscopolamine · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Gastrointestinal
- **Also known as:** Buscopan, Butylscopolamine, Hyoscine butylbromide, N-butylscopolammonium bromide
- **Species with doses:** Horses
- **General dose range:** 0.3 mg/kg IV single dose — check the species tables for the indication
- **Routes:** IV
- **Last reviewed:** 1 October 2026

## Indications

- Spasmodic / flatulent colic and simple impactions (horses)
- Oesophageal obstruction (choke) — with oxytocin in geldings/stallions
- Bronchospasm relief (diagnostic/short-term)

## Hyoscine Butylbromide (N-Butylscopolammonium) dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Horses

*Hyoscine Butylbromide (N-Butylscopolammonium) doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Spasmodic colic / bronchoconstriction | 0.3 mg/kg | IV | single dose (slow IV) | — |
| Oesophageal obstruction (choke) | 0.3 mg/kg | IV | once, with oxytocin | — |

- Spasmodic colic / bronchoconstriction: Papich 5e and Plumb’s p.881 (label): 0.3 mg/kg (1.5 mL per 100 kg of 20 mg/mL) slowly IV once; onset within 2 min, duration <2 h.
- Oesophageal obstruction (choke): Plumb’s p.881 (Beard 2008): 0.3 mg/kg IV once with oxytocin 0.11–0.22 U/kg IV; avoid or greatly reduce oxytocin in mares and do not use in pregnant mares.

## Contraindications

Ileus or suspected strangulating lesion where masking signs is dangerous; tachyarrhythmias; glaucoma. Combination products with metamizole (dipyrone) are dosed differently — check the label.

## Adverse effects

- Transient tachycardia (~30 min)
- Reduced GI sounds
- Mydriasis, dry mucous membranes

## Formulations and products

- Injection 20 mg/mL

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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## Frequently asked questions

### What is the dose of Hyoscine Butylbromide (N-Butylscopolammonium) for horses?

Reference doses for Hyoscine Butylbromide (N-Butylscopolammonium) in horses: 0.3 mg/kg IV single dose (slow IV) (Spasmodic colic / bronchoconstriction); 0.3 mg/kg IV once, with oxytocin (Oesophageal obstruction (choke)). Confirm against the label and the patient before use.

### When should Hyoscine Butylbromide (N-Butylscopolammonium) not be used?

Ileus or suspected strangulating lesion where masking signs is dangerous; tachyarrhythmias; glaucoma. Combination products with metamizole (dipyrone) are dosed differently — check the label.

### What are the side effects of Hyoscine Butylbromide (N-Butylscopolammonium) in animals?

Transient tachycardia (~30 min); Reduced GI sounds; Mydriasis, dry mucous membranes.

## Sources

- Plumb's Veterinary Drug Handbook
- Papich 5e — N-Butylscopolammonium Bromide
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.