# Neostigmine: veterinary dose and monograph

> Neostigmine is a veterinary drug. Quaternary cholinesterase inhibitor: reverses non-depolarising neuromuscular blockade, diagnoses and treats myasthenia gravis, and stimulates GI (rumen, colon) motility. Indications include reversal of non-depolarising neuromuscular blockade (atracurium); diagnosis and short-term treatment of myasthenia gravis; large-colon ileus (horses); rumen atony (ruminants). This monograph lists 9 reference doses for dogs, cats, cattle, horses, goats and sheep and 1 more species, each with route, frequency and source, plus meat and milk withdrawal periods for food animals.

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

## At a glance

- **Drug class:** Veterinary drug
- **Also known as:** Neostigmine methylsulfate, Prostigmin, Stiglyn
- **Species with doses:** Dogs, Cats, Cattle, Horses, Goats, Sheep and Pigs
- **General dose range:** 0.02–0.04 mg/kg IM as needed — check the species tables for the indication
- **Routes:** IM, SC
- **Last reviewed:** 1 October 2026

## Indications

- Reversal of non-depolarising neuromuscular blockade (atracurium)
- Diagnosis and short-term treatment of myasthenia gravis
- Large-colon ileus (horses); rumen atony (ruminants)

## Neostigmine 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.

### Dogs

*Neostigmine doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Myasthenia gravis — diagnostic test | 0.04–0.05 mg/kg | IM | single dose (pre-treat with atropine) | — |
| Myasthenia gravis — parenteral treatment (regurgitating) | 0.04 mg/kg | IM | q6h | — |
| Reversal of neuromuscular blockade | 0.04 mg/kg | IM | once (with atropine or glycopyrrolate) | — |

- Myasthenia gravis — diagnostic test: Papich 5e: 40 µg/kg IM or 20 µg/kg IV. Plumb’s p.886 (LeCouteur): 0.05 mg/kg IM — improvement within 15–30 min supports MG; pre-treat with atropine.
- Myasthenia gravis — parenteral treatment (regurgitating): Plumb’s p.886 (Inzana 2000): 0.04 mg/kg IM q6h until oral pyridostigmine can be given. Papich 5e: 10 µg/kg IM or SC as needed (not for long-term use); oral 2 mg/kg/day divided.
- Reversal of neuromuscular blockade: Papich 5e: 40 µg/kg IM or SC as an antidote for neuromuscular blockade. Give only once recovery has begun (train-of-four); ventilate until adequate.

### Cats

*Neostigmine doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Myasthenia gravis / NMB reversal | 0.04 mg/kg | IM | q6h (MG) or once (reversal) | — |

- Myasthenia gravis / NMB reversal: Plumb’s p.886 (Inzana 2000): 0.04 mg/kg IM q6h for regurgitating cats. Papich 5e (dogs and cats): reversal 40 µg/kg IM or SC; diagnosis 40 µg/kg IM or 20 µg/kg IV.

### Cattle

*Neostigmine doses for cattle*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Rumen atony / GI stimulation | 0.02–0.022 mg/kg | SC | repeat as indicated | — | Withdrawal NOT established — treat as extra-label |

- Rumen atony / GI stimulation: Papich 5e: 22 µg/kg SC; rumen motility 0.02 mg/kg IM or SC. Plumb’s p.886 (label): 1 mg per 100 lb SC. Rule out obstruction first. Follow the local label or FARAD for withdrawal.

### Horses

*Neostigmine doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Large-colon ileus / NMB reversal | 0.02–0.044 mg/kg | SC | q2–6h (ileus) or as needed | — |

- Large-colon ileus / NMB reversal: Papich 5e: 0.02–0.04 mg/kg IV or SC, or CRI 0.008 mg/kg/h. Plumb’s p.886: 0.022 mg/kg IV or 0.044 mg/kg SC/IM — no value in small-intestinal ileus (White); 0.025 mg/kg SC q2–6h (Hassel); 2 mg per 500 kg every 30–60 min to 10 mg total (Hallowell). May cause colic. ARCI Class 3.

### Goats

*Neostigmine doses for goats*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Rumen atony / GI stimulation | 0.01–0.02 mg/kg | SC | repeat as indicated | — | Withdrawal NOT established — treat as extra-label |

- Rumen atony / GI stimulation: Plumb’s p.886 (Davis 1986, sheep and goats): 0.01–0.02 mg/kg.

### Sheep

*Neostigmine doses for sheep*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Rumen atony / GI stimulation | 0.01–0.033 mg/kg | SC | repeat as indicated | — | Withdrawal NOT established — treat as extra-label |

- Rumen atony / GI stimulation: Papich 5e: 22–33 µg/kg SC. Plumb’s p.886: 1–1.5 mg per 100 lb SC (label); 0.01–0.02 mg/kg (Davis).

### Pigs

*Neostigmine doses for pigs*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| GI stimulation | 0.03–0.066 mg/kg | IM | repeat as indicated | — | Withdrawal NOT established — treat as extra-label |

- GI stimulation: Papich 5e: 44–66 µg/kg IM. Plumb’s p.886: 2–3 mg per 100 lb IM (label); 0.03 mg/kg (Davis).

### Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

*Neostigmine doses for buffalo*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Rumen atony / GI stimulation | 0.02–0.022 mg/kg | SC | repeat as indicated | — | Withdrawal NOT established — treat as extra-label |

- Rumen atony / GI stimulation: Papich 5e: 22 µg/kg SC; rumen motility 0.02 mg/kg IM or SC. Plumb’s p.886 (label): 1 mg per 100 lb SC. Rule out obstruction first. Follow the local label or FARAD for withdrawal.

## Contraindications

Mechanical GI or urinary obstruction, peritonitis, bradycardia or AV block, asthma/bronchospasm. Do not use for small-intestinal ileus in horses (no benefit, colic). Depolarising blockers (succinylcholine) are prolonged, not reversed.

## Adverse effects

- Salivation, diarrhoea, urination (muscarinic)
- Bradycardia
- Bronchospasm
- Muscle fasciculation / cholinergic weakness at high doses
- Colic (horses)

## Toxicity and overdose

Management: Cholinergic crisis (salivation, diarrhoea, bradycardia, weakness): atropine 0.02–0.04 mg/kg IV/IM, ventilatory support.

## Formulations and products

- Injection 0.5 mg/mL
- Injection 2 mg/mL (1:500, large animal)

## 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 Neostigmine for dogs?

Reference doses for Neostigmine in dogs: 0.04–0.05 mg/kg IM single dose (pre-treat with atropine) (Myasthenia gravis — diagnostic test); 0.04 mg/kg IM q6h (Myasthenia gravis — parenteral treatment (regurgitating)); 0.04 mg/kg IM once (with atropine or glycopyrrolate) (Reversal of neuromuscular blockade). Confirm against the label and the patient before use.

### What is the dose of Neostigmine for cats?

Reference doses for Neostigmine in cats: 0.04 mg/kg IM q6h (MG) or once (reversal) (Myasthenia gravis / NMB reversal). Confirm against the label and the patient before use.

### What is the dose of Neostigmine for cattle?

Reference doses for Neostigmine in cattle: 0.02–0.022 mg/kg SC repeat as indicated (Rumen atony / GI stimulation). Confirm against the label and the patient before use.

### What is the withdrawal period for Neostigmine?

Cattle, SC (Rumen atony / GI stimulation): Withdrawal NOT established — treat as extra-label; Goats, SC (Rumen atony / GI stimulation): Withdrawal NOT established — treat as extra-label; Sheep, SC (Rumen atony / GI stimulation): Withdrawal NOT established — treat as extra-label; Pigs, IM (GI stimulation): Withdrawal NOT established — treat as extra-label. Follow the product label and national regulations where they differ.

### When should Neostigmine not be used?

Mechanical GI or urinary obstruction, peritonitis, bradycardia or AV block, asthma/bronchospasm. Do not use for small-intestinal ileus in horses (no benefit, colic). Depolarising blockers (succinylcholine) are prolonged, not reversed.

### What are the side effects of Neostigmine in animals?

Salivation, diarrhoea, urination (muscarinic); Bradycardia; Bronchospasm; Muscle fasciculation / cholinergic weakness at high doses; Colic (horses).

## Sources

- Plumb's Veterinary Drug Handbook
- Papich 5e — Neostigmine
- 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.