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Generic name: racepinephrineRAYSE-ep-i-NEF-rin ]
Brand names: Asthmanefrin, S2 Inhalant
Drug class: Adrenergic bronchodilators

Medically reviewed by on Dec 1, 2023. Written by Cerner Multum.

What is Asthmanefrin?

Asthmanefrin is a bronchodilator. It works by relaxing muscles in the airways to improve breathing.

Asthmanefrin is used to relieve occasional symptoms of asthma, such as wheezing, chest tightness, and feeling short of breath.

Asthmanefrin may also be used for purposes not listed in this medication guide.

Asthmanefrin side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Asthmanefrin may cause serious side effects. Call your doctor at once if you have:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Do not use Asthmanefrin if you have used an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, or tranylcypromine.

Before taking this medicine

Do not use Asthmanefrin unless you have asthma that has been confirmed by a doctor.

You should not use Asthmanefrin if you are allergic to it.

Do not use Asthmanefrin if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.

Ask a doctor or pharmacist if it is safe for you to use this medicine if you have other medical conditions, especially:

It is not known whether Asthmanefrin will harm an unborn baby. Do not use this medicine without a doctor's advice if you are pregnant.

It is not known whether racepinephrine passes into breast milk or if it could harm a nursing baby. Do not use this medicine without a doctor's advice if you are breast-feeding a baby.

Do not give this medicine to a child younger than 4 years old without medical advice.

How should I use Asthmanefrin?

Use exactly as directed on the label, or as prescribed by your doctor. Do not take more than the recommended dose. Using too much Asthmanefrin or using it too often can increase your risk of heart attack or stroke, which can cause death.

Asthmanefrin is a liquid solution that must be placed into a hand-held bulb nebulizer. You will inhale the medicine from the nebulizer.

Any child using Asthmanefrin should be supervised by an adult while using this medicine.

After using Asthmanefrin, your symptoms should improve within 20 minutes.

Call your doctor right away if your symptoms do not improve within 20 minutes, or if they get worse after using Asthmanefrin.

Asthma is usually treated with a combination of drugs. Use all medications as directed by your doctor. Read the medication guide or patient instructions provided with each medication. Do not change your doses or medication schedule without your doctor's advice.

Seek medical attention if you think your medications are not working as well.

Signs that your asthma symptoms may be getting worse include:

Store at room temperature away from moisture, heat, and light. Do not freeze.

Do not use Asthmanefrin if it looks brown or cloudy. Throw it out and get a new supply of racepinephrine.

What happens if I miss a dose?

Since Asthmanefrin is used when needed, you may not be on a dosing schedule. If you are on a schedule, use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

Do not use more than 12 inhalations of racepinephrine in a 24-hour period.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using Asthmanefrin?

Avoid getting Asthmanefrin in your eyes.

Avoid eating or drinking products that contain caffeine, such as coffee, tea, soft drinks, or energy drinks. Taking caffeine while you are using Asthmanefrin can increase your blood pressure.

What other drugs will affect Asthmanefrin?

Tell your doctor about all your current medicines and any you start or stop using, especially:

This list is not complete. Other drugs may interact with racepinephrine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.