Primidone is used on its own or together with other medicines to treat epilepsy (also known as fits or seizures).
This medicine is also used in the management of essential tremor (shaking attacks).
Take Primidone 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.
You may take this medicine with or without food. Swallow the tablet whole with a glass of water. Try to take it at the same time each day.
Primidone must be taken regularly for it to be effective. Continue taking Primidone even when you feel better. Do not stop taking it suddenly as this may worsen your condition.
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.
Alert your doctor if you have acute intermittent porphyria (an inherited disorder of metabolism that may cause nervous system abnormalities) as Primidone may not be suitable for you.
Inform your doctor if you have the following conditions:
- suicidal tendencies
- history of drug abuse
- hypoadrenalism (disorder of the adrenal glands)
- lung disease
- kidney disease
- liver disease
- physical or mental weakness, usually due to illness or old age
Let your doctor know if you are pregnant. Primidone may cause harm to your unborn child.
It is important that you do not get pregnant while taking this medicine. You must use proven birth control methods during Primidone therapy and for 2 months after stopping the treatment. Birth control medicines containing hormones may not be effective. You may wish to discuss other reliable methods of birth control with your doctor.
Inform your doctor if you are breastfeeding.
Be sure to check with your doctor or pharmacist before giving this medicine to a child or the elderly. Children or elderly people may be more sensitive to the side effects.
In case of prolonged treatment, your doctor may give you Vitamin D supplementation.
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
- Pregnancy test may be done before treatment to know if this medicine is suited for you to take.
- Routine tests (e.g. blood primidone and phenobarbital levels, blood folate levels, complete blood count, bone density scans) may be done while you are being treated with this medicine.
- Regular monitoring of signs of depression or suicidal thoughts may also be needed.
Your doctor will advise you about how often you need to have these tests.
Primidone may cause drowsiness and reduced alertness. If affected, do not drive or take part in any activity in which you need to be alert.
Other side effects include any of the following: nausea, vomiting, tiredness, rashes, joint pain, headache and dizziness.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- rashes with peeling of the skin or blistering of the lips, mouth or eyes accompanied by fever
- shortness of breath, muscle weakness, abnormal skin paleness, fast heartbeat
- having thoughts of self-harm
This medicine may cause the level of your red blood cells to drop. Red blood cells carry oxygen around your body. A fall in the level of red blood cells may make you feel tired and worn out.
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Inform your doctor and pharmacist if you are taking any of these medicines:
- certain antibiotics e.g. chloramphenicol, doxycycline, metronidazole
- other medicines for epilepsy (fits) e.g. felbamate, carbamazepine, sodium valproate
- certain medicines for cancer e.g. cyclophosphamide, etoposide
- blood-thinning medicines e.g. dicoumarin, warfarin
- medicine for high blood pressure or heart disease e.g. digitoxin, losartan, quinidine
- montelukast, theophylline (asthma medicines)
- nelfinavir (medicine for HIV infection)
- ciclosporin (medicine used in organ transplant or certain immune disorders)
- clozapine (medicine for mood disorders)
- corticosteroids (anti-inflammatory medicine)
- granisetron (medicine for nausea or vomiting)
- methadone (a strong painkiller)
- mianserin (medicine to treat depression)
- nimodipine (medicine that relaxes blood vessels in the brain)
- St. John’s wort (herbal medicine)
Alert your doctor if you are taking birth control pills or other types of hormonal birth control. You may need to add on another type of birth control.
This list does not include all medicines that may interact with Primidone.
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.
Avoid alcohol. Alcohol intake may worsen the drowsiness caused by Primidone.
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.