| Active Ingredients: Phenobarbital
Representative Names: Solfoton
How does it work?
This medicine contains the active ingredient phenobarbital (previously known as phenobarbitone in the UK), which belongs to a group of medicines called barbiturates. It is an antiepileptic medicine that can be used to regulate the activity of nerves.
The brain and nerves are made up of many nerve cells that communicate with each other through electrical signals. These signals must be carefully regulated for the brain and nerves to function properly.
When abnormally rapid and repetitive electrical signals are released in the brain, it becomes over-stimulated and normal function is disturbed. This results in fits or seizures.
GABA is a chemical that, when released in the brain, acts as a natural calming agent and keeps the nerve activity in balance. Once the brain absorbs the GABA (uptake), this chemical can no longer act on the nerves. Too little GABA, the brain may become overexcited. Other chemicals in the brain act directly on nerve cells causing an increase in nerve activity.
Phenobarbital is thought to mainly act by preventing chemicals from passing through openings on the nerve cells. In addition, phenobarbital acts to increase the effects of GABA and decrease the effect of other chemicals such as glutamate that excite nerve activity.
This results in stabilised electrical nerve activity in the brain, leading to prevention of fits and maintenance of normal brain function.
What is it used for?
Warning!
- This medicine may reduce your ability to drive or operate machinery safely. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won't affect your performance.
- Avoid stopping this medicine suddenly, as it may result in insomnia, anxiety, tremor, dizziness, nausea, delirium and convulsions.
Use with caution in
- Children
- Decreased kidney function
- Decreased liver function
- Diabetes mellitus
- Elderly people
- History of alcoholism or drug abuse
- History of asthma
- Hyperactivity
- Ongoing pain that suddenly worsens
- Senility
- Severe anaemia
- Slow, shallow breathing (respiratory depression)
Not to be used in
- Allergy to any medication in the barbiturate group
- Dangerously slow, shallow breathing (severe respiratory depression)
- Life long inherited blood diseases which can cause a variety of symptoms, including mental health problems (porphyrias)
- Severe kidney disease
- Severe liver disease
This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and Breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- This medicine is not to be used during pregnancy, especially during the first and third trimesters.
- This medicine should not be used by breastfeeding mothers. Discuss this with your doctor.
Label warnings
- Do not stop taking this medication except on your doctor's advice.
- This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.
Side effects
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
- Drowsiness
- Slow, shallow breathing (respiratory depression)
- Excitement
- Confusion
- Blood disorders
- Hyperactivity
- Disturbances in behaviour
- Shaky movements and unsteady walk (ataxia)
- Rapid involuntary movements of the eyes (nystagmus)
- Depressed mood
- Allergic skin reactions
The side effects listed above may not include all of the side effects reported by the drug's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
There is a risk of increased sedation when Phenobarbital is taken with alcohol or sodium valproate.
Phenobarbital may decrease the blood levels of:
Anti-arrhythmic medications (disopyramide and quinidine)
Antibiotics (chloramphenicol, doxycycline, metronidazole and rifampicin)
Anti-clotting medications (warfarin and dicoumarol)
Anti-epileptic medications (carbamazepine, lamotrigine, phenytoin and sodium valproate)
Blood pressure lowering medications (felodipine, nimodipine and verapamil)
Corticosteroids such as prednisolone
Ciclosporin
Digoxin
Fenoprofen
Mianserin
Oral and depot contraceptives
Paracetamol
Phenothiazines such as chlorpromazine
Phenylbutazone
Theophylline
and tricyclic antidepressant medications such as amitriptyline.
Phenobarbital may decrease the effectiveness of griseofulvin.
The effectiveness of phenobarbital may be decreased by other anti-epileptic medication (eg phenytoin) or antidepressants (eg amitriptyline).
Phenobarbital may cause the body to need larger amounts of vitamin D. In addition, when phenobarbital is taken with acetazolamide, there is an increased risk of the occurrence of bone softening due to lack of vitamin D. |
