Primidone SERB 250mg Tablets

Patient Leaflet Updated 24-Jan-2022 | SERB

PRIMIDONE SERB 50mg-250mg tablet

Package leaflet: Information for the user

Primidone SERB

50mg and 250mg Tablets


Read all of this leaflet carefully before you start taking this medicine because it contains important information for you.

  • 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.

What is in this leaflet:

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

1. What Primidone SERB is and what it is used for

Primidone contains primidone as the active ingredient; this belongs to a group of medicines used to treat seizures.

Primidone is used for the treatment of certain types of epilepsy, seizures (fits) or shaking attacks (essential tremor).

2. What you need to know before you take Primidone SERB

Do not take Primidone:

  • If you are allergic to primidone, phenobarbital, or to any of the other ingredients of this medicine (these are listed in Section 6: Further information).
  • If you have porphyria (a rare inherited disorder of metabolism) or anyone in your family has it.

Warnings and precautions

This medication is not effective in certain forms of epilepsy. Your doctor will assess the need to prescribe you this medicine depending on the form of epilepsy you are suffering from.

Consult your doctor immediately if the frequency of your seizures increases or if seizures of a different type appear.

Talk to your doctor or pharmacist before taking Primidone:

  • If you have ever had respiratory, kidneys or liver problems;
  • If you are pregnant or are trying to become pregnant (see beneath for further information).

If you go into hospital, tell the medical staff that you are taking Primidone.

Your doctor may prescribe you Vitamin D supplementation (in case of long-term treatment).

A small number of people being treated with anti-epileptics such as primidone have had thoughts of harming or killing themselves. If at any time you have these thoughts, immediately contact your doctor.

Potentially life-threatening skin rashes (Stevens-Johnson syndrome, toxic epidermal necrolysis or DRESS syndrome) have been reported with the use of Primidone, appearing initially as reddish target-like spots or circular patches often with central blisters on the trunk.

Additional signs to look for include ulcers in the mouth, throat, nose, genitals and conjunctivitis (red and swollen eyes).

These potentially life-threatening skin rashes are often accompanied by flu-like symptoms. The rash may progress to widespread blistering or peeling of the skin.

The highest risk for occurrence of serious skin reactions is within the first weeks of treatment.

If you have developed Stevens-Johnson syndrome, toxic epidermal necrolysis or DRESS syndrome with the use of Primidone or any other medicine containing phenobarbital, you must not be re-started on these medicines at any time.

If you develop a rash or these skin symptoms, stop using primidone and seek immediate advice from a doctor and tell him that you are taking this medicine.

Other medicines and Primidone

Tell your doctor or pharmacist if you are taking, have recently taken, or might take any other medicines. This is important because some medicines may affect the way Primidone works, or Primidone may affect the way other medicines work.

In particular, tell your doctor if you are taking any of the following:

  • Other medicines used to treat epilepsy and other types of seizures (such as phenytoin, felbamate, valproic acid, carbamazepine, perampanel, lamotrigine, oxcarbazepine, stiripentol, tiagabine, zonisamide)
  • Anticoagulants to prevent blood clots (such as acenocoumarol, fluindione, phenindione, warfarin)
  • Barbiturates or benzodiazepines (such as sleeping tablets)
  • Medicines used to treat severe pain, cough, or as a substitute for morphine addiction (such as methadone, oxycodone or fentanyl)
  • Antibiotics (such as metronidazole, doxycycline, telithromycine)
  • Asthma medicines (such as theophylline, montelukast)
  • Hormone containing medicines (such as the oral contraceptive pill, estroprogestatives, progestatives, ulipristal)
  • Thyroid hormones,
  • Medicines used to treat high blood pressure or heart conditions (such as beta-blockers, nimodipine)
  • Cyclosporine (used to prevent rejection of an organ transplant and also for other diseases of the body’s immune system)
  • Medicines used to treat mental health problems or depression (such as lurasidone, tricyclic antidepressants, lamotrigine, mianserin, quetiapine, sertraline)
  • Steroid-containing medicines
  • Medicines used to treat cancer (such as cyclophosphamide, etoposide, abiraterone, axitinib, eribuline, ifosfamide, bosutinib, crizotinib, dabrafenib, dasatinib, erlotinib, gefitinib, imatinib, lapatinib, nilotinib, pazopanib, ruxolitinib, sorafenib, sunitinib, vandetanib, regorafenib, vemurafenib, vismodegib, cabozantinib, ceritinib, ibrutinib, olaparib, ponatinib, carbazitaxel, docetaxel, irinotecan, procarbazine),
  • St-John’s wort
  • Medicines containing morphine or similar medicines called opiates.
  • Bedaquiline, delamanid (used to treat tuberculosis),
  • Quinine (used to treat malaria),
  • Medicines used to treat viral infections such as HIV infection or hepatitis C (such as boceprevir, cobicistat, daclatasvir, dasabuvir, dolutegravir, lopinavir, maraviroc, nelfinavir, ombitasvir+paritaprevir, rilpivirine, ritonavir, simeprevir, sofosbuvir, telaprevir),
  • Anti-fungal medicines (voriconazole, albendazole, itraconazole, posaconazole),
  • Anticoagulants (such as apixaban, dabigatran, rivaroxaban or ticagrelor),
  • Folates (vitamin B9),
  • Medicines used to reduce immunity (immune-suppressants, such as cyclosporine, tacrolimus, sirolimus, everolimus),
  • Deferasirox (iron-chelator),
  • Medicine used to treat cystic fibrosis (ivacaftor),
  • Medicines used to treat a heart disease, high blood pressure or to regulate cardiac rhythms (such as class IA antiarythmics, calcium antagonists, bosentan, dronedarone, ivabradine, macitentan, nimodipine, propafenone, ranolazine or betablockers (metoprolol, propranolol),
  • Antiparasite agent (albendazole, praziquantel).

Taking Primidone with food, drink and alcohol

Alcohol can react with Primidone. Ask your doctor for advice if you want to drink alcohol.

Pregnancy, breast-feeding and fertility

The use of Mysoline in pregnancy is associated with an increased risk of abnormalities in babies. Primidone is likely to cause malformations in the unborn child (especially cleft lip and palate, cardiovascular malformations and abnormality of the penis in male babies) when administered during pregnancy. Therefore, you must tell your doctor if you are pregnant, or trying to become pregnant

Your doctor will talk to you about potential benefit of continuation of the treatment or whether another medication maybe more suitable for you. If you continue treatment,

  • During pregnancy: your doctor will adjust your dose to get the minimum effective dose for you. Before delivery: you will need to take vitamin K to prevent the bleeding this medicine may cause during the first 24 hours of your baby's life.
  • After childbirth: an injection of vitamin K may also be prescribed to your baby, at birth, to avoid any bleeding.

Do not interrupt your treatment suddenly; this could lead to the recurrence of seizures, which would have serious consequences for you and your child.

It is recommended that you use effective contraception during treatment. Primidone can make the contraceptive pill ineffective and you should use another effective method of contraception - ask your doctor for advice regarding effective contraception.

Effects in the new born

The new born child may develop withdrawal symptoms if the mother has taken Mysoline in the late stages of pregnancy. Blood clotting problems have occurred occasionally in children born to women who were previously taking anticonvulsant drugs.

Breast-feeding is not recommended as Primidone is found in breat milk and can make the baby sleepy. Contact your doctor if you are breastfeeding or want to breastfeed.

Driving and using machines

Primidone can make you feel sleepy. If so, do not drive or operate machinery.

3. How to take Primidone SERB

Always take Primidone exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure.

The dosage will be determined by your doctor and adjusted gradually on individual basis.

Primidone is normally taken twice a day. Try to take your tablets at the same time each day.

Swallow the tablets whole with a drink of water.

The tablet can be divided into equal doses.


At first, your dose may be as little as 125mg (half a 250mg tablet). This will be adjusted by your doctor until your condition is controlled. Typical maintenance doses are as follows:

For adults and children over 9 years, the daily dose is 750 to 1500mg

For children 6 to 9 years, the daily dose is 750 to 1000mg

For children 2 to 5 years, the daily dose is 500 to 750mg

For children up to 2 years, the daily dose is 250 to 500mg

Shaking attacks (Essential tremor)

Your starting dose may be 50 mg. This will be adjusted by your doctor until your condition is controlled. The highest dose tolerated for shaking attacks (essential tremor) is up to a maximum of 750 mg.

Elderly / Patients with renal or liver disease

Lower doses may be prescribed. Please check with your doctor.

If you take more Primidone than you should

If you take more than your normal dose, contact your doctor or nearest hospital.

If you forget to take Primidone

If you miss a dose, take it as soon as you remember. Do not take a double dose to make up for a forgotten tablet.

If you stop taking Primidone

Do not stop taking your Primidone, even if you are feeling well, unless your doctor tells you to. You may have become dependent on Primidone, and therefore you could get a withdrawal reaction if you stop treatment too quickly. Primidone treatment should be reduced gradually to prevent this.

If you have any further questions on the use of this product, ask your doctor or pharmacist.

4. Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them.

Common (may affect up to 1 in 10 people)

  • lack of energy (apathy), coordination disorders, visual disturbances, rolling of the eyes.
  • nausea.

Uncommon (may affect up to 1 in 100 people)

  • Headache, vertigo
  • Vomiting
  • Allergic skin reaction

Rare (may affect up to 1 in 1,000 people)

  • Decreased number of some blood cells (red blood cells or white blood cells or platelets) or development of lymph nodes.
  • Changes in mood or behaviour
  • Joint or bone pain, Dupuytren’s contracture (a thickening of fibrous tissue in the palm of the hand that causes one or more fingers to draw back), osteomalacia (bone softening due to vitamin D deficiency)
  • Exfoliative dermatitis (common redness and peeling of the skin), lupus eythematous (disease which causes inflammation of various parts of the body including the skin, joints, lungs, kidneys, heart and live
  • Raised levels of enzymes in your liver (gamma GT, alkaline phosphatase)

Very rare (may affect up to 1 in 10,000 people)

  • Potentially life-threatening skin rashes (Stevens-Johnson syndrome, toxic epidermal necrolysis) have been reported (see section 2).

Not known (frequency cannot be estimated from the available data)

  • Allergic reactions which may include fever, rash, increased numbers of some blood cells (eosinophils), increased of some liver enzymes
  • There have been reports of bone disorders including osteopenia and osteoporosis (thinning of the bone) and fractures. Check with your doctor or pharmacist if you are on long-term antiepileptic medication, have a history of osteoporosis, or take steroids.
  • Potentially life-threatening skin rashes (drug rash with eosinophilia and systemic symptoms) have been reported (see section 2).

Reporting of side effects

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 the Yellow Card Scheme (Website: By reporting side effects you can help provide more information on the safety of this medicine.

5. How to store Primidone

Keep out of the reach and sight of children

Keep your tablets below 25°C.

Do not use Primidone after the expiry date which is stated on the carton as {EXP MM/YYYY}. The expiry date refers to the last day of that month.

Medicines should not be disposed of via wastewater or household waste. Ask your pharmacist how to dispose of medicines no longer required. These measures will help to protect the environment.

6. Contents of the pack and other information

What Primidone contains

The active substance is primidone. Each tablet contains either 50 mg or 250 mg of primidone. The other ingredients are carmellose calcium, gelatin, magnesium stearate, povidone K30 and stearic acid, which are all typical ingredients used in tablet manufacture.

What Primidone looks like and contents of the pack

Primidone SERB 50 mg Tablets are white uncoated tablets for oral use. One side of the tablet has a single letter M, the other side of the tablet is plain.

Primidone SERB 250 mg Tablets are white uncoated tablets for oral use. One side of the tablet has the letter M either side of a break-line. The other side of the tablet is plain.

Primidone comes in bottles of 100 tablets or blisters containing 10 tablets each.

Marketing Authorisation Holder

40, avenue George V
75008 Paris


Recipharm Limited
Vale of Bardsley

Allphamed PHARBIL Arzneimittel GmbH
Hildebrandstr. 10-12
37081 Göttingen

This leaflet was last approved in December 2021.

Is this leaflet hard to see and read? Phone 0800 198 5000 for help.

If you have any medical enquiry, please email [email protected]

Company Contact Details

40, avenue George V, 75008 Paris, France


00 33 1 73 03 20 00


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