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Generic name: moricizine [ mor-IH-siz-een ]
Brand name: Ethmozine

Moricizine sometimes produces new irregular heartbeats (arrhythmias). Therefore, it should be used in carefully selected patients. Consult your doctor or pharmacist for more information.

Moricizine is used for:

Treating irregular heartbeat.

Moricizine is an antiarrhythmic. It works by making the heart tissue less sensitive, which brings an irregular or fast heartbeat to a normal rhythm.

Do NOT use moricizine if:

  • you are allergic to any ingredient in moricizine
  • you have heart block or heart shock

Contact your doctor or health care provider right away if any of these apply to you.

Before using moricizine:

Some medical conditions may interact with moricizine. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have liver problems, heart problems, high or low levels of potassium in the blood, or low levels of magnesium in the blood

Some MEDICINES MAY INTERACT with moricizine. Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Anticoagulants (eg, warfarin) because the risk of bleeding may be increased

This may not be a complete list of all interactions that may occur. Ask your health care provider if moricizine may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use moricizine:

Use moricizine as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Moricizine may be taken with or without food.
  • Hospitalization is required when starting moricizine.
  • Serious heartbeat disturbances can result from taking too much or too little of moricizine. Dose changes should be supervised by your doctor.
  • If you miss a dose of moricizine, take it if you remember within 4 hours. If it is more than 4 hours since your missed dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use moricizine.

Important safety information:

  • Moricizine may cause dizziness. Do not drive, operate machinery, or do anything else that could be dangerous until you know how you react to moricizine. Using moricizine alone, with certain other medicines, or with alcohol may lessen your ability to drive or perform other potentially dangerous tasks.
  • Before you have any medical or dental treatments, emergency care, or surgery, tell the doctor or dentist that you are using moricizine.
  • LAB TESTS, including electrocardiogram (ECG) monitoring, may be required to monitor your progress. Be sure to keep all doctor and lab appointments.
  • Use moricizine with extreme caution in CHILDREN. Safety and effectiveness have not been confirmed.
  • PREGNANCY and BREAST-FEEDING: If you become pregnant while taking moricizine, discuss with your doctor the benefits and risks of using moricizine during pregnancy. Moricizine is excreted in breast milk. Do not breast-feed while taking moricizine.

Possible side effects of moricizine:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Dizziness; headache; nausea; tiredness.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; fast, irregular, or slow heartbeat; shortness of breath; swelling of the legs or ankles.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center (, or emergency room immediately. Symptoms may include difficulty breathing; fainting; unconsciousness; vomiting.

Proper storage of moricizine:

Store moricizine at room temperature, between 59 and 86 degrees F (15 and 30 degrees C). Store away from heat, moisture, and light. Do not store in the bathroom. Keep moricizine out of the reach of children and away from pets.

General information:

  • If you have any questions about moricizine, please talk with your doctor, pharmacist, or other health care provider.
  • Moricizine is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.
  • Check with your pharmacist about how to dispose of unused medicine.

This information is a summary only. It does not contain all information about moricizine. If you have questions about the medicine you are taking or would like more information, check with your doctor, pharmacist, or other health care provider.

Issue Date: June 3, 2015

Further information

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