Mexiletine - oral

Patient Medicine Information
Why do I need this medicine?
Mexiletine is used to treat abnormal heart rhythm.

This medicine may be used to treat other conditions as decided by your doctor.
How do I take this medicine?
Take Mexiletine exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.

Take it together with food or immediately after a meal. Try to take it at the same time each day.

The dose of this medicine will be decided by your doctor. Your doctor will advise you on the course of treatment depending on your condition and response to the medication.

Mexiletine must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed by the doctor.
What should I do if I have forgotten to take this medicine?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.

DO NOT double a dose under any circumstances.

If you often forget to take your medicine, let your doctor and pharmacist know.
When should I not use this medicine?
Alert your doctor if you have the following conditions:
  • heart block particularly if without a pacemaker (a device placed in the chest that helps control your heartbeat)
  • cardiogenic shock (a condition caused by the inability of the heart to pump enough blood for the body)
as Mexiletine may not be suitable for you.
What should I take note of while taking this medicine?
Inform your doctor if you have the following conditions:
  • other heart problems e.g. heart failure, recent heart attack
  • low blood pressure
  • epilepsy (fits or seizures)
  • low or high potassium levels in the blood
  • low magnesium levels in the blood
  • liver disease
Let your doctor know if you are pregnant or breastfeeding.

Why is it important to keep my appointments with the doctor?

Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
  • Routine tests such as electrocardiogram or ECG (a test used to record the electrical activity of the heart), electrolyte levels and liver function tests may be done before and while you are being treated with this medicine. Your doctor will advise you how often you need to have these tests.
  • Your blood pressure may fall to unsafe levels without you noticing it. Monitor your blood pressure regularly during treatment.
What side effects could I experience?
Mexiletine may cause blurred vision, confusion, or tiredness. If affected, do not drive or take part in any activity in which you need to be alert or need to see clearly.

Other side effects include any of the following: headache, stomach discomfort, nausea, vomiting, constipation, diarrhoea, weakness, nervousness, difficulty sleeping, tremor, and difficulty in controlling or coordinating movements such as unsteadiness in walking.

Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
  • worsening of abnormal or irregular heartbeats
  • frequent and persistent sore throat with fever; unusual bleeding or bruising
  • yellowing of the skin or eyes, abdominal pain, dark coloured urine, swelling in the legs and ankles
  • fits or seizures
  • rashes with peeling of the skin or blistering of the lips, mouth or eyes accompanied by fever
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Can I take this with other medicines?
Inform your doctor and pharmacist if you are taking any of these medicines:
  • other medicines for irregular heartbeat e.g. amiodarone, quinidine, flecainide
  • medicines for epilepsy (fits or seizures) e.g. phenytoin, phenobarbital
  • fluvoxamine (medicine for depression)
  • theophylline (medicine for asthma)
  • medicines for TB (infection known as tuberculosis) e.g. rifampicin, rifapentine
  • cimetidine (medicine that reduces stomach acid production)
  • caffeine-containing medicines
This list does not include all medicines that may interact with Mexiletine.

Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
What special dietary instructions should I follow?
Avoid alcohol and foods that may markedly affect the acidity of your urine. Ask your doctor about the types of food you should avoid.
How should I store this medicine?
Store in a cool, dry place away from the reach of children.

Medicines must not be used past the expiry date.
This information is independently developed by MIMS based on mexiletine - oral and is provided for your reference only. It is not a replacement for and should only be used in conjunction with full consultation with a licensed healthcare professional, the information provided by your pharmacist and/or the manufacturer of the medication. It may not contain all the available information you require and cannot substitute professional medical care, nor does it take into account all individual circumstances. Although great effort has been made to ensure content accuracy, we shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by
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