Ephedrine
Ephedrine sulfate
Also known as: Enurace · Ephedrine sulphate · Ephedrine hydrochloride · Ephedrini hydrochloridum
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of bronchospasm (maintenance therapy) | 1-2 mg/kg PO q8-12h | PO | q8-12h | — | 🌎 NA |
| Treatment of bronchospasm | 2 mg/kg PO q8-12h | PO | q8-12h | — | 🌎 NA |
| Treatment of urinary incontinence | 5-15 mg (total dose) PO q8h | PO | q8h | — | 🌎 NA |
| Treatment of urinary incontinence | 1.2 mg/kg PO q8h or 5-15 mg (total dose) PO q8h | PO | q8h | — | 🌎 NA |
| Treatment of hypotension associated with anesthesia | 0.03-0.1 mg/kg IV bolus | IV | Once, may repeat in 5 minutes | — | 🌎 NA |
| Treatment of hypotension associated with anesthesia | 0.1-0.25 mg/kg IV bolus | IV | Once | — | 🌎 NA |
| Treatment of hypotension associated with anesthesia | 0.1-0.2 mg/kg IV bolus | IV | Once | 15-60 minutes | 🌎 NA |
| Treatment of hypotension associated with anesthesia | 0.15-0.25 mg/kg IV boluses OR CRI at 5-10 micrograms/kg/minute | IV | To effect or CRI | — | 🌎 NA |
| Hypotension during anaesthesia | Dose not specified in monograph | IV/IM | As needed (effects wane after 2-3 doses) | Perioperative | 🌍 EU |
| Urinary incontinence | Dose not specified in monograph | PO | Not specified | Long-term | 🌍 EU |
- Treatment of hypotension associated with anesthesia: Dilute 5 mg in 10 mL of saline and give the lower dosage first as sinus tachycardia may accompany the higher dose.
- Treatment of hypotension associated with anesthesia: For relatively short procedures in ASA I or II patients when hypotension is not responsive to 1 or 2 crystalloid boluses.
- Treatment of hypotension associated with anesthesia: Dilute into 5 mL of a balanced electrolyte solution or saline and give small increment IV boluses until desirable blood pressure achieved.
- Hypotension during anaesthesia: Assists in bradycardia. Tachyphylaxis occurs rapidly.
- Urinary incontinence: Exclude polyuria before treatment. Can be used with phenylpropanolamine.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Treatment of bronchospasm (emergency treatment) | 2-5 mg PO | PO | Once | — | 🌎 NA |
| Treatment of urinary incontinence | 2-4 mg (total dose) PO q8h | PO | q8h | — | 🌎 NA |
| Treatment of urinary incontinence | 2-4 mg/kg PO q6-12h or 2-4 mg (total dose) PO q8h | PO | q6-12h or q8h | — | 🌎 NA |
| Treatment of urinary incontinence | 2-4 mg per cat PO q8-12h | PO | q8-12h | — | 🌎 NA |
| Treatment of hypotension associated with anesthesia | 0.15-0.25 mg/kg IV boluses OR CRI at 5-10 micrograms/kg/minute | IV | To effect or CRI | — | 🌎 NA |
| Hypotension during anaesthesia | Dose not specified in monograph | IV/IM | As needed | Perioperative | 🌍 EU |
| Nasal congestion (cat 'flu') | Dose not specified in monograph | topical | Not specified | Short-term | 🌍 EU |
- Treatment of hypotension associated with anesthesia: Dilute into 5 mL of a balanced electrolyte solution or saline and give small increment IV boluses until desirable blood pressure achieved.
- Hypotension during anaesthesia: Use with caution.
- Nasal congestion (cat 'flu'): Proposed for treatment of nasal congestion; may be of some benefit.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Ephedrine is a non-catecholamine sympathomimetic amine. In veterinary medicine, it is primarily utilized for the management of urethral sphincter mechanism incompetence (USMI) in dogs and cats, though phenylpropanolamine (PPA) is often preferred due to a lower incidence of CNS side effects.
Additionally, it serves as an injectable vasopressor to combat anesthesia-induced hypotension and as a bronchodilator for respiratory conditions.
Clinical Pearl: Because ephedrine crosses the blood-brain barrier more readily than many other sympathomimetics, it can cause mild to moderate CNS stimulation, which manifests as restlessness or agitation in some patients.
Mechanism of action
Ephedrine is a mixed-acting sympathomimetic.
- Indirect Action (Primary): It enters the sympathetic nerve terminal and promotes the release of stored norepinephrine into the synaptic cleft.
- Direct Action (Secondary): It directly stimulates α- and β-adrenergic receptors.
Key Pathways:
- α1-receptors → Smooth muscle contraction → Increased internal urethral sphincter tone (improving continence) and peripheral vasoconstriction (increasing blood pressure).
- β1-receptors → Positive inotropic and chronotropic effects on the heart → Increased cardiac output.
- β2-receptors → Smooth muscle relaxation → Bronchodilation.
Note: Because it relies heavily on endogenous norepinephrine stores, repeated frequent dosing can deplete these stores, leading to tachyphylaxis (diminished response over time).
Safety & warnings
Contraindications
- Severe cardiovascular disease
- Cardiac arrhythmias
- Pregnancy
- Lactation
- Glaucoma
Adverse effects
- Irritability
- Tachycardia
- Hypertension
- Anorexia
- Tachyphylaxis (decreased response to subsequent doses)
- Panting
- Mydriasis (dilated pupils)
- CNS stimulation (restlessness, agitation)
- Atrial fibrillation
- Vasoconstriction
- Reduction of intestinal wall motility and tone
Precautions
Use with caution in patients with glaucoma, prostatic hypertrophy, hyperthyroidism, diabetes mellitus, cardiovascular disorders, or hypertension.
When administered IV, the administration rate should be carefully controlled (in humans, not to exceed 10 mg/minute; scale appropriately for veterinary patients).
Pregnancy/Nursing: FDA Category C. Excreted in milk and may have deleterious effects on nursing animals. Consider milk replacer if use is absolutely necessary in a nursing dam.
Drug interactions
Phenothiazines block alpha-adrenergic receptors; concomitant use can lead to unopposed beta-activity causing vasodilation and increased cardiac rate.
May negate the therapeutic effects of ephedrine.
Increased risk of arrhythmias. Propranolol may be administered should these occur.
Concomitant use may diminish the effects of both drugs.
Increased risk of arrhythmias if used concurrently.
Should not be given within two weeks of receiving MAOIs; severe hypertension and hyperpyrexia are possible.
Should not be administered together as increased toxicity may result.
May reverse the pressor effects of ephedrine.
May increase the risk for theophylline toxicity.
May decrease the pressor effects of ephedrine.
May reduce urinary excretion of ephedrine and prolong its duration of activity, potentially requiring dosage adjustments.
Synergistic effects, increasing the risk of adverse cardiovascular and CNS stimulation.
Enhances the sensitivity of the myocardium to the arrhythmogenic effects of ephedrine.
Concomitant use can cause severe cardiac arrhythmias.
Concomitant use can cause severe cardiac arrhythmias.
May cause severe hypertension when given concurrently.
Concomitant use with tricyclic antidepressants can cause arrhythmias.
Concomitant use with MAO inhibitors may cause severe hypertension.
Can be used in conjunction for urinary incontinence, but increases sympathetic load.
Monitoring
- Clinical effectiveness (resolution of incontinence, improved blood pressure, or bronchodilation)
- Behavioral changes (restlessness, irritability)
- Heart rate and rhythm (ECG during anaesthesia)
- Resolution of urinary incontinence
- Signs of CNS stimulation or excessive panting
Pharmacokinetics
Absorption
Rapidly absorbed after oral or parenteral administration.
Distribution
Thought to cross both the blood-brain barrier and the placenta.
Metabolism
Metabolized in the liver.
Elimination
Excreted unchanged in the urine. Urine pH may significantly alter excretion characteristics.
Overdose
Clinical signs of overdosage may consist of an exacerbation of adverse effects (restlessness, tachycardia).
In a very large overdose, severe cardiovascular signs (hypertension leading to rebound hypotension, bradycardias to tachycardias, and cardiovascular collapse) or CNS effects (ranging from severe stimulation to coma) can be seen.
Treatment:
- If the overdose was recent, empty the stomach using usual precautions.
- Administer activated charcoal and a cathartic.
- Treat clinical signs supportively as they occur.
Available products
Formulations
- Capsules
- 10 mg tablet
- 15 mg tablet
- 30 mg tablet
- 50 mg tablet
- 3 mg/ml solution for injection
- 30 mg/ml solution for injection
- 0.5% nasal drops
- 1% nasal drops
Veterinary
- Enurace 10 mg, 15 mg, 30 mg, 50 mg tablets
Human-labeled
- Ephedrine Sulfate Capsules: 25 mg
- Ephedrine Sulfate Injection: 50 mg/mL in 1 mL single-dose vials & preservative free in 1 mL single-dose amps
- Ephedrine hydrochloride 3 mg/ml, 30 mg/ml solutions for injection
- Ephedrine 0.5%, 1% nasal drops
Regulatory status
POM-V classification in the UK/EU.
POM-V, POM.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store ephedrine sulfate products in tight, light-resistant containers at room temperature unless otherwise directed. When used parenterally, ephedrine sulfate is usually administered directly and not diluted.
Client information
- Consistency is Key: In order for this drug to be effective for urinary incontinence, it must be administered exactly as directed by your veterinarian. Missed doses will negate its effect and leaking may return.
- Patience: It may take several days for the full benefit of the drug to take place.
- Side Effects: Because this medication acts like a stimulant, it can cause your pet to feel "jittery". Contact your veterinarian if your pet demonstrates ongoing changes in behavior (restlessness, irritability, pacing) or if incontinence persists or increases.
- Timing: To prevent sleep disturbances, try not to give the final dose of the day right before bedtime unless instructed otherwise.
- Appetite: You may notice a temporary decrease in your pet's appetite.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.