• Keep this leaflet. You may need to read it again.
• If you have any further questions, ask your doctor or pharmacist.
• This medicine has been prescribed for you only. Do not pass it on to others. It may harm them, even if their signs of illness are the same as yours.
• If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. See section 4.

There is an Alert Card distributed with Namuscla, to remind you and medical staff of the risk of cardiac arrythmias. Read the Alert Card in conjunction with this leaflet and keep the card it with you at all times.

1. What Namuscla is and what it is used for
2. What you need to know before you take Namuscla
3. How to take Namuscla
4. Possible side effects
5. How to store Namuscla
6. Contents of the pack and other information

• if you are allergic to mexiletine or to any of the other ingredients of this medicine (listed in section 6)
• if you are allergic to any local anaesthetic
• if you have had heart attack
• if your heart does not work well enough
• if you have certain disorders of the heart rhythm
• if your heart beats too fast
• if the blood vessels of your heart are damaged
• if you also take certain medicines to treat disorders of the heart rhythm (see Other medicines and Namuscla)
• if you also take certain medicines which have a narrow therapeutic window (see Other medicines and Namuscla).

If you have any doubt, ask your doctor or pharmacist.

Talk to your doctor or pharmacist or nurse before taking Namuscla if you have:

• heart problems
• liver problems
• kidney problems
• low or high potassium blood levels
• low magnesium blood levels
• epilepsy

Heart function

Before starting treatment with Namuscla, you will have tests to check how well your heart is working, including ECG (Electrocardiogram). These tests will also be performed regularly during treatment with Namuscla, and before and after your dose of Namuscla is modified. How often these tests will be performed depends on your heart function.

If you or your doctor detects any heart rhythm disturbances or any of the conditions stated in section “Do not take Namuscla”, your doctor will stop your treatment with Namuscla.

If you notice that the rhythm of your heart changes (the heart beats faster or slower), if you feel fluttering or pain in your chest, if you have difficulty breathing, if you feel dizzy, if you sweat or if you faint, you have to contact an emergency centre immediately.

Some patients may have higher blood levels of Namuscla because of slower break down in the liver and the dose may need to be adjusted accordingly.

Namuscla should not be used in children and adolescents younger than 18 years old.

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines.

Do not take Namuscla with certain medicines for treating heart rhythm disorders (quinidine, procainamide, disopyramide, ajmaline, encainide, flecainide, propafenone, moricizine, amiodarone, sotalol, ibutilide, dofetilide, dronedarone, vernakalant). See section “Do not take Namuscla”. Taking Namuscla together with any of these medicines increases the risk of a serious heart rhythm disturbance called torsades de pointes.

Do not take Namuscla with certain medicines which have a so called narrow therapeutic window (these are medicines where small differences in dose or blood concentration may impact the effect of the medicine or side effects). Examples of such medicines are digoxin (for heart problems), lithium (mood stabiliser), phenytoin (for treating epilepsy), theophylline (against asthma) and warfarin (against blood clots).

Tell your doctor or pharmacist if you are taking any of the following since these medicines may affect or be affected by Namuscla:

• medicines for heart problems (lidocaine, tocainide, propranolol, esmolol, metoprolol, atenolol, carvedilol, bisoprolol, nebivolol, verapamil, diltiazem),
• certain other medicines:
  • timolol for treating high pressure in the eye (glaucoma),
  • certain antibiotics (ciprofloxacin, rifampicin),
  • certain antidepressants (fluvoxamine),
  • tizanidine (used to relax the muscles),
  • metformin (used against diabetes)
  • omeprazole (to treat stomach ulcer and gastric acid reflux).

Tell your doctor or pharmacist if you start to smoke or quit smoking while taking Namuscla because smoking impacts the Namuscla blood levels and your dose may need to be adjusted accordingly .

It is recommended to reduce your caffeine intake by half while on treatment with mexiletine because the medicine can increase caffeine levels in your blood.

If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor for advice before taking this medicine. If you become pregnant while taking Namuscla, see your doctor immediately as it is preferable not to take Namuscla while you are pregnant. If you become pregnant while taking Namuscla, see your doctor immediately.

Mexiletine passes into human milk. You should talk to your doctor about this, together you will make a decision whether to abstain breast-feeding or to discontinue/abstain from mexiletine therapy.

Namuscla may in rare cases cause tiredness, confusion, blurred vision: If you have these effects do not drive, cycle and use machines.

Contact your doctor if you take more than the recommended dose of Namuscla. This could be very harmful to your health. You or your companion should contact the doctor immediately if you have tingling in the arms and legs, if you feel unable to think clearly or concentrate, if you have hallucinations, convulsions, if you feel that your heart beats slower, if you feel dizzy and faint, if you collapse or if your heart stops beating.

If you have forgotten a dose, do not take a double dose and take the next dose at your regular schedule.

If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine.

Each hard capsule contains:

• mexiletine hydrochloride corresponding to 166.62 mg of mexiletine (active substance)
• Other ingredients (maize starch, colloidal anhydrous silica, magnesium stearate, gelatin, iron oxide [E 172], titanium dioxide [E 171]).

Namuscla hard capsules are reddish hard gelatin capsules filled with white powder.

Namuscla is available in blister packs containing 30, 50, 100 or 200 capsules.

Not all pack sizes may be marketed.