- if you are allergic to phenytoin, or any of the other ingredients of this medicine (listed in section 6).
- if you are allergic to other medicines with a similar chemical structure to phenytoin (e.g. hydantoins)
Talk to your doctor or pharmacist before taking Phenytoin sodium. Medicines are not always suitable for everyone. Your doctor needs to know before you take phenytoin if you suffer from or have suffered in the past from any of the following conditions:
- liver disease
- kidney disease
- Porphyria (an inherited disease that affects haemoglobin biosynthesis)
The following symptoms have been reported in some people treated with phenytoin at recommended doses:
- shortness of breath, becoming unconscious, or unresponsive. All can be the symptoms of the sudden, unexpected stopping of the heart (known as cardiac arrest). If you or someone you know is taking Phenytoin and experiencing these symptoms, seek immediate medical support.
- severe allergic reactions like swelling of the eyelids, face, lips, mouth and / or throat, as well as the tongue may cause difficulty in breathing or swallowing (known as angioedema) and sudden wheeziness.
All these can be symptoms leading to a sudden, unexpected stopping of the heart (known as cardiac arrest). Stop taking your medicine and seek immediate medical help.
- slower heartbeat (known as bradycardia).
A small number of people being treated with antiepileptics such as phenytoin sodium 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) have been reported with the use of Phenytoin Tablets, 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, including fever at the initiation of treatment. 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 or toxic epidermal necrolysis with the use of Phenytoin Tablets, you must not be re-started on Phenytoin Tablets at any time.
If you develop a rash or these skin symptoms, stop taking Phenytoin Tablets, seek urgent advice from a doctor and tell them that you are taking this medicine. Consult your doctor before permanently discontinuing Phenytoin Tablets. If you suddenly stop taking this medicine you may have a seizure.
Talk to you doctor before taking Phenytoin tablets if you are of Taiwanese, Japanese, Malaysian or Thai origin and tests have shown that you carry the genetic variant CYP2C9*3.
Serious skin side effects can rarely occur during treatment with phenytoin. This risk may be associated with a variant in genes in a subject with Chinese or Thai origin. If you are of such origin and have been tested previously carrying this genetic variant (HLA-B*1502), discuss this with your doctor before taking Phenytoin tablets.
There is a risk of harm to the unborn child if Phenytoin tablets are used during pregnancy. Women of childbearing age should use effective contraception during treatment with Phenytoin tablets (see Pregnancy, contraception in women and breast-feeding).
Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines.
Some medicines can affect the way Phenytoin works, or Phenytoin itself can reduce the effectiveness of other medicines taken at the same time. These include:
- Medicines used for heart and circulation problems (amiodarone, digoxin, furosemide, reserpine, ticagrelor, warfarin, and calcium channel blockers e.g. diltiazem, mexiletine, nicardipine, nifedipine, nimodipine, disopyramide and verapamil)
- Medicines used to lower blood cholesterol, (e.g. atorvastatin, fluvastatin and simvastatin)
- Medicines used for epilepsy (carbamazepine, lacosamide, lamotrigine, oxcarbazepine, phenobarbital, sodium valproate, topiramate and valproic acid, succinimides e.g. ethosuximide and vigabatrin)
- Medicines used to treat fungal infections (e.g. amphotericin B, fluconazole, itraconazole, ketoconazole, miconazole, posaconazole and voriconazole)
- Medicines used for tuberculosis and other infections (chloramphenicol, clarithromycin, isoniazid, rifampicin, sulphonamides, sulfadiazine, sulfamethoxazole-trimethoprim, doxycycline, ciprofloxacin, efavirenz, fosamprenavir, indinavir, lopinavir/ritonavir, ritonavir and saquinavir).
- Medicines used for stomach ulcers (omeprazole, sucralfate, the medicines known as H2 antagonists e.g. cimetidine and some antacids)
- Medicines used for asthma and bronchitis (theophylline)
- Medicines used for pain and inflammation (salicylates e.g.aspirin and steroids)
- Medicines used for sleeplessness, depression and psychiatric disorders (chlordiazepoxide, clozapine, diazepam, disulfiram, fluoxetine, methylphenidate, paroxetine, phenothiazines, trazodone, tricyclic antidepressants, fluvoxamine, quetiapine and sertraline)
- Medicines used for diabetes (tolbutamide)
- Some hormone replacement therapies (oestrogens), oral contraceptives (the birth control pill)
- Medicines used for organ and tissue transplants, to prevent rejection (ciclosporin and tacrolimus).
- Medicines used for cancer (antineoplastic agents) e.g. bleomycin, capecitabine, carboplatin, cisplatin, doxorubicin, fluorouracil and methotrexate)
- Muscle relaxants used for surgery (neuromuscular blockers), some anaesthetic drugs (methadone)
- Medicines used as anticoagulants (e.g. rivaroxaban, dabigatran, apixaban, edoxaban)
- Some products available without a prescription (folic acid, theophylline, St John’s Wort, vitamin D)
Your doctor may need to test the amount of Phenytoin in your blood to help decide if any of these medicines are affecting your treatment.
The herbal preparation St John’s wort (Hypericum perforatum) should not be taken at the same time as this medicine. If you already take St John’s wort, consult your doctor before stopping the St John’s wort preparation.
Phenytoin tablets may also interfere with certain laboratory tests that you may be given.
Phenytoin tablets can be taken before or after food and drinks.
Drinking a lot of alcohol can also affect the concentration of Phenytoin in your blood.
Pregnancy
What you should know about the use of antiepileptic drugs in pregnancy
If you are pregnant, or think you may be pregnant, you must tell your doctor straight away and discuss possible risks the epilepsy medicine you are taking might pose to your unborn baby.
If you are planning to become pregnant you should discuss your epilepsy treatment with your doctor as early as possible before you become pregnant.
You should not stop your treatment without discussing this with your doctor. Suddenly stopping may lead to breakthrough seizures which may harm you and your unborn baby. It is important that your epilepsy is well controlled.
Taking phenytoin during pregnancy increases the chance that the baby may have a physical birth abnormality.
Studies with women treated with phenytoin for epilepsy during pregnancy have shown that around 6 babies in every 100 will have serious physical birth abnormalities. This compares to 2-3 babies in every 100 born to women who don’t have epilepsy.
The most common types of serious physical birth abnormalities (major congenital malformations) reported for phenytoin include abnormalities of the lip and palate, heart, skull, nail and finger disorders and growth abnormalities. Some of these may occur together as part of a foetal hydantoin syndrome.
Taking more than one epilepsy medicine at the same time may also increase the risk of physical birth abnormalities. Where possible, your doctor will consider using one epilepsy medicine only to control your epilepsy.
Your doctor may advise you to take folic acid if you’re planning to become pregnant and while you’re pregnant. Your doctor may adjust your epilepsy medicine when you take folic acid.
Some studies observed that taking phenytoin during pregnancy increases the chance that the baby may have problems affecting learning and thinking abilities.
If you take Phenytoin tablets during pregnancy, your baby is also at risk for bleeding problems right after birth. Your doctor may give you and your baby a medicine to prevent this. Moreover, your child should be closely monitored.
Contraception in women
If you are of childbearing age and are not planning a pregnancy, you should use effective contraception during treatment with Phenytoin tablets. Phenytoin may affect how hormonal contraceptives, such as the contraceptive (birth control) pill, work and make them less effective at preventing pregnancy. Talk to your doctor, who will discuss with you the most suitable type of contraception to use while you are taking phenytoin.
Breast-feeding
Phenytoin Tablets passes into breast milk. You should not take Phenytoin Tablets if you are breast-feeding.
Phenytoin may cause dizziness or drowsiness, especially during the first few weeks of treatment. If you experience these symptoms do not drive or use any tools or machinery.
This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially ‘sodium-free’.
Always take this medicine exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure.
It is best to take Phenytoin tablets at the same time each day.
Swallow the tablets whole, with plenty of water
The amount of Phenytoin Tablets needed varies from one person to another. Most adults need between 200mg and 500mg a day either as a single or divided dose. Occasionally higher doses are needed.
Infants and children usually start on a dose that depends on their weight (5mg per day for every kg they weigh) and is given as a divided dose, twice a day. The dose is then adjusted up to a maximum of 300mg a day.
The dose of Phenytoin Tablets for elderly patients, patients with kidney or liver disease, or those who may be taking other medicines may also need careful consideration and adjustment by their doctor.
Phenytoin is dangerous in overdose. If you accidentally take too many Phenytoin tablets contact your doctor at once or go to the nearest hospital casualty department. Always take the labelled medicine package with you, whether there are any Phenytoin tablets left or not.
If you forget to take a dose, take it as soon as you remember unless it is time for your next dose. Do not take a double dose to make up for a forgotten dose.
Do not stop taking Phenytoin tablets unless your doctor tells you to.
If you suddenly stop taking this medicine you may have a seizure.
Should you need to stop taking Phenytoin tablets, your doctor will have decided which is the best method for you.
If you have any further questions on the use of this medicine, ask your doctor or pharmacist.
- The active substance is Phenytoin sodium. Each film-coated tablet contains 100 mg of phenytoin sodium.
- The other ingredients are
Tablet core:
Mannitol
Crospovidone
Magnesium stearate
Croscarmellose sodium
Tablet coat:
Hypromellose
Macrogol 400
Titanium dioxide
Sodium lauryl sulfate
White to off-white, oval shaped, film-coated tablets debossed with ‘C’ on one side and ‘70’ on the other side.
Polyamide/Aluminium/PVC//Aluminium blister pack:
10, 14, 20, 28, 30, 50, 60, 84, 100, 112, 200 and 250 film-coated tablets
HDPE container with a polypropylene closure and silica gel dessicant:
30 film-coated tablets
Not all pack sizes may be marketed.
Milpharm Limited
1 Roundwood Avenue
Stockley Park
Uxbridge
UB11 1AF
United Kingdom
APL Swift Services (Malta) Limited
HF26
Hal Far Industrial Estate
Hal Far
Birzebbugia
BBG 3000
Malta
or
Milpharm Limited
1 Roundwood Avenue
Stockley Park
Uxbridge
UB11 1AF
United Kingdom