Esmolol is a beta-blocker that is used to help keep the heart beating normally in people with certain heart rhythm disorders of the atrium (the upper chambers of the heart that allow blood to flow into the heart). Esmolol is used in people with atrial fibrillation or atrial flutter.

Esmolol is also used during surgery to help regulate blood pressure and heart rate.

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

You should not be treated with esmolol if you have a serious heart condition ("sick sinus syndrome" or "AV block"), very slow heartbeats, heart failure, pulmonary hypertension, or if you are receiving certain IV heart or blood pressure medications.

In an emergency, you may not be able to tell caregivers about your health conditions. Make sure any doctor caring for you afterward knows you received esmolol.

Esmolol is given as an infusion into a vein. A healthcare provider will give you this injection.

Your breathing, blood pressure, oxygen levels, and other vital signs will be watched closely while you are receiving esmolol.

You should not be treated with esmolol if you are allergic to it, or if you have:

• a serious heart condition such as "sick sinus syndrome" or "AV block" (second or third degree);

• a history of slow heart beats that have caused you to faint;

• severe heart failure;

• pulmonary hypertension (increased pressure inside the blood vessels of the lungs and heart); or

• a condition for which you are being treated with intravenous (IV) heart or blood pressure medication (such as diltiazem, nicardipine, or verapamil).

If possible before you receive esmolol, tell your doctor if you have ever had:

• a heart condition called Prinzmetal's angina;

• asthma, chronic obstructive pulmonary disease (COPD), or other breathing disorder;

• diabetes;

• pheochromocytoma (tumor of the adrenal gland);

• overactive thyroid;

• allergies;

• kidney disease;

• coronary artery disease (hardened arteries); or

• peripheral vascular disease such as Raynaud's syndrome.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant.

You should not breast-feed while using this medicine.

In an emergency, you may not be able to tell caregivers if you are pregnant or breast feeding. Make sure any doctor caring for your pregnancy or your baby knows you received this medicine.

Because you will receive esmolol in a clinical setting, you are not likely to miss a dose.

Since esmolol is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

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

Tell your caregivers right away if you have:

• a light-headed feeling, like you might pass out;

• very slow heartbeats;

• swelling in your hands or feet;

• wheezing, chest tightness, feeling short of breath;

• weak or shallow breathing;

• pain, swelling, irritation, bruising, or skin changes around the IV needle;

• cold feeling in your hands and feet;

• high potassium--nausea, slow or unusual heart rate, weakness, loss of movement; or

• low blood sugar--headache, hunger, sweating, irritability, dizziness, nausea, fast heart rate, and feeling anxious or shaky.

Common side effects of esmolol may include:

• increased sweating;

• nausea;

• dizziness, drowsiness; or

• low blood pressure.

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.

Tell your doctor about all your other medicines, especially:

• digoxin, digitalis;

• blood pressure medication;

• diet pills, stimulants, ADHD medication (Ritalin, Adderall, and others);

• insulin or oral diabetes medicine; or

• medicines to treat asthma, colds, or allergies.

This list is not complete. Other drugs may affect esmolol, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.