# Metoprolol: veterinary dose and monograph

> Metoprolol is a veterinary cardiovascular drug. A CARDIOSELECTIVE (β1-selective) beta-blocker — used for supraventricular and some ventricular tachyarrhythmias, rate control, systemic hypertension, and dynamic outflow obstruction in feline hypertrophic cardiomyopathy. Indications include supraventricular tachycardia / rate control; feline HCM with dynamic LV outflow obstruction; systemic hypertension (adjunct). This monograph lists 2 reference doses for dogs and cats, each with route, frequency and source.

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

## At a glance

- **Drug class:** Cardiovascular
- **Also known as:** Lopressor, Metolar, Metpure, Betaloc
- **Species with doses:** Dogs and Cats
- **General dose range:** 0.2–1 mg/kg PO q8h — check the species tables for the indication
- **Routes:** PO
- **Last reviewed:** 1 October 2026

## Indications

- Supraventricular tachycardia / rate control
- Feline HCM with dynamic LV outflow obstruction
- Systemic hypertension (adjunct)
- Some catecholamine-driven ventricular arrhythmias

## Metoprolol 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

*Metoprolol doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Arrhythmia / hypertension | 0.2–1 mg/kg | PO | q8h | — |

- Arrhythmia / hypertension: Papich 5e: 0.5–1 mg/kg (5–50 mg per dog) PO q8h. Plumb’s p.825: AF rate control 0.25–1 mg/kg PO q12–24h (Saunders); CHF — start 0.2 mg/kg q12h and titrate every 2–3 weeks (many dogs will not tolerate up-titration; Rush); sustained-release 0.4–1 mg/kg q24h peri-operatively (Orton). Start low; do not stop abruptly.

### Cats

*Metoprolol doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| HCM / arrhythmia | 2–15 mg per cat PO q8h, titrated to heart rate | PO | q8h | — |

- HCM / arrhythmia: Papich 5e and Plumb’s p.825 (Brovida 2002): 2–15 mg per cat PO q8h. Atenolol is more commonly used in cats. Do not stop abruptly.

## Contraindications

Decompensated congestive heart failure, significant bradyarrhythmia / high-grade AV block, and hypotension. Severe bronchospastic disease (selectivity is lost at high doses). Diabetes (masks hypoglycaemia). Abrupt withdrawal (rebound). Known hypersensitivity.

## Species-specific warnings

> **Caution:** Cats: Useful in HCM but avoid in decompensated heart failure; monitor for bradycardia/hypotension. Atenolol is commonly preferred in cats.

## Adverse effects

- Bradycardia, hypotension, lethargy
- Negative inotropy — can worsen heart failure
- Bronchoconstriction at higher (non-selective) doses
- Masks hypoglycaemia; GI upset

## Drug interactions

- Calcium-channel blockers (diltiazem/verapamil): additive bradycardia/AV block/myocardial depression
- Other negative chronotropes (digoxin): additive AV slowing
- Sympathomimetics (terbutaline/salbutamol): mutual antagonism
- CYP2D6 inhibitors: increased metoprolol levels; insulin: masks hypoglycaemia

## Pregnancy and lactation

Beta-blockers may cause fetal bradycardia/growth effects; use only if maternal benefit outweighs risk.

## Monitoring

- Heart rate, rhythm (ECG), blood pressure
- Signs of worsening CHF; respiratory status
- Blood glucose in diabetics; taper to discontinue

## Toxicity and overdose

Overdose: profound bradycardia, AV block, hypotension, heart failure, bronchospasm and CNS depression/hypoglycaemia. Cardioselectivity reduces (but does not eliminate) bronchospasm risk. Potentially life-threatening in overdose.

Management: GLUCAGON is the key antidote for beta-blocker overdose; plus atropine, IV fluids, high-dose catecholamines, and consider high-dose insulin-euglycaemia therapy/IV lipid emulsion for refractory cases. Treat bronchospasm and hypoglycaemia; continuous ECG.

## Clinical pearls

- A cardioselective (β1) beta-blocker — preferable to propranolol when airway disease coexists (less bronchospasm at usual doses)
- Atenolol (q12–24h, renally cleared) is the more common veterinary cardioselective choice; metoprolol q8h is an alternative
- Glucagon is the overdose antidote; never stop abruptly (rebound) and avoid in decompensated CHF
- Start low and titrate to heart rate/rhythm with ECG guidance

## Mechanism of action

A β1-selective adrenoceptor antagonist. β1 blockade slows sinus rate and AV conduction, reduces myocardial contractility and oxygen demand, and lowers blood pressure/renin release; in HCM it relieves catecholamine-driven dynamic outflow obstruction. Its relative β1 selectivity spares bronchial β2 receptors at usual doses (less bronchospasm than propranolol), though selectivity diminishes at high doses.

## Formulations and products

- 25 / 50 mg tablet
- 100 mg tablet (incl. extended-release)
- Injection 1 mg/mL
- Metolar / Metpure — 25 / 50 / 100 mg tablet (XL forms), Tablet (human-label)
- Betaloc / Lopressor — 25 / 50 mg tablet; 1 mg/mL injection, Tablet / injection (human-label)

## Storage

Tablets/injection: 15–30 °C, protect from light.

## 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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- [Phenylephrine](https://vetmasterji.com/drugs/phenylephrine)

## Frequently asked questions

### What is the dose of Metoprolol for dogs?

Reference doses for Metoprolol in dogs: 0.2–1 mg/kg PO q8h (Arrhythmia / hypertension). Confirm against the label and the patient before use.

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

Reference doses for Metoprolol in cats: 2–15 mg per cat PO q8h, titrated to heart rate PO q8h (HCM / arrhythmia). Confirm against the label and the patient before use.

### When should Metoprolol not be used?

Decompensated congestive heart failure, significant bradyarrhythmia / high-grade AV block, and hypotension. Severe bronchospastic disease (selectivity is lost at high doses). Diabetes (masks hypoglycaemia). Abrupt withdrawal (rebound). Known hypersensitivity.

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

Bradycardia, hypotension, lethargy; Negative inotropy — can worsen heart failure; Bronchoconstriction at higher (non-selective) doses; Masks hypoglycaemia; GI upset.

## Sources

- Plumb's Veterinary Drug Handbook
- Merck Veterinary Manual, 11th edition
- 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.