Nausea, vomiting, heartburn, dizziness, lightheadedness, vision problems (such as blurred vision), headache, shaking, nervousness, or problems with muscle control (coordination difficulties) may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor immediately if any of these rare but serious side effects occur: worsening symptoms of heart failure (such as ankle/leg swelling, increased tiredness, increased shortness of breath when lying down), signs of liver problems (such as persistent nausea/vomiting, stomach/abdominal pain, yellowing eyes/skin, dark urine).

Seek immediate medical attention if any of these rare but very serious side effects occur: chest pain, seizure.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Read the Mexitil (mexiletine hcl) Side Effects Center for a complete guide to possible side effects »

PRECAUTIONS: Before taking mexiletine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: other heart problems (such as heart failure, slow heartbeat, previous heart attack), liver problems, seizure disorder.

This drug may make you dizzy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Limit alcoholic beverages.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk. However, this drug is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.