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Active substance(s): PHENOBARBITAL

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Patient information leaflet


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,
pharmacist or nurse.
• 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
or nurse. This includes any possible side effects not listed in
this leaflet. See section 4.
What is in this leaflet:
1. What Phenobarbital is and what it is used for
2. What you need to know before you take Phenobarbital
3. How to take Phenobarbital Tablets
4. Possible side effects
5. How to store Phenobarbital Tablets
6. Contents of the pack and other information

1. What Phenobarbital is and what it is used for

Phenobarbital belongs to a group of drugs known as
barbiturates. Phenobarbital is used to treat all forms of
epilepsy except absence seizures. In an epileptic fit excessive
electrical activity builds up in the brain. Phenobarbital works
by neutralising this excessive electrical activity.

2. What you need to know before you take

DO NOT TAKE these tablets if you:
• have previously suffered an allergic reaction to a medicine
containing Phenobarbital or other barbiturates
• are allergic to any of the other ingredients in this medicine
(see section 6)
• suffer from the rare condition porphyria (a genetic or
inherited disorder of red blood pigment haemoglobin)
• have long-term kidney or liver problems
• have difficulty breathing
Warnings and precautions
Talk to your doctor or pharmacist before taking these tablets
if you:
• are young, run down, senile
• have a history of drug abuse or alcoholism
• have kidney or liver problems
• have breathing difficulties
• have severe or long-term pain

If you develop a rash or the following skin symptoms, seek
immediate advice from a doctor and tell him or her that
you are taking this medicine:
• Potentially life threatening skin rashes (Stevens-Johnson
syndrome, toxic epidermal necrolysis) have been reported
with the use of Phenobarbital tablets appearing initially as
reddish target-like spots or circular patches often with
central blisters on the trunk. Additional signs to look for
include ulcer 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 rashes 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 use of Phenobarbital tablets you
must not be restarted on Phenobarbital tablets at anytime.
A small number of people being treated with anti-epileptics
such as Phenobarbital have had thoughts of harming or killing
themselves. If at any time you have these thoughts,
immediately contact your doctor.
Other medicines and Phenobarbital
Tell your doctor or pharmacist if you are taking, have
recently taken or might take any other medicines, especially:

• anticoagulants, medicines used to thin the blood (e.g.


• chloramphenicol, an antibiotic used to treat eye and ear


• doxycycline, metronidazole, telithromycin, itraconazole,

posaconazole, voriconazole, abacavir, amprenavir,
lopinavir, darunavir, indinavir, nelfinavir and saquinavir
(to treat infection)
• griseofulvin, a drug used to treat fungal infections of the
• systemic steroids including oral contraceptives (talk to
your doctor about the best method of contraception for
you) or tibolone (hormone replacement treatment)
• ciclosporin or tacrolimus, which are used in organ and
tissue transplants
• other medicines used to treat epilepsy, e.g. oxcarbazepine,
primidone, phenytoin, lamotrigine, carbamazepine, sodium
valproate, tiagabine, zonisamide, ethosuxamide and
• phenylbutazone, which is used to treat a painful condition
of the spine
• rifampicin, a drug used to treat tuberculosis
• phenothiazines, chlorpromazine, thioridazine, haloperidol,
aripiprazole and clonazepam which are used to treat
psychiatric disorders
• mianserin, paroxetine, monoamine oxidase inhibitors
(MAOIs), tricyclic antidepressants or the herbal remedy St
John’s wort (all used to treat depression), should not be
taken at the same time as this medicine. If you already take
St John’s wort (Hypericum perforatum), consult your
doctor before stopping the St John’s wort preparation
• medicine used to treat heart trouble or high blood
pressure, e.g. nifedipine, felodipine, isradipine, verapamil
and nimodipine, diltiazem, metoprolol, timolol and
• digitoxin or eplerenone, disopyramide, quinidine (to treat
certain heart conditions)
• thyroxine and levothyroxine, which is used to treat a
disorder of the thyroid gland
• steroid such as hydrocortisone or prednisolone
• folic acid or vitamin D (supplements)
• tormifene, gestronone, irinotecan or etoposide (to treat
some cancer)
• methadone (used in severe pain or drug addiction)
• montelukast or theophylline (to treat asthma)
• tropisetron and aprepitant (to treat nausea and vomiting)
• sodium oxybate (to treat narcolepsy)
• methylphenidate (to treat Attention Deficit Hyperactivity
• memantine (to treat dementia)
Do not drink alcohol while taking this medicine without
asking your doctor.

Pregnancy and breast feeding
If you are pregnant or planning to become pregnant you
should speak to your doctor before taking Phenobarbital. If
you become pregnant whilst taking Phenobarbital your doctor
will decide if you should continue taking this medicine or
whether another would be more suitable during pregnancy.
Do not stop taking Phenobarbital until you have seen your
doctor as it is important to control your fits.
If taken during pregnancy (particularly in the first 3 months
and the last 3 months), Phenobarbital may cause birth defects.
It may also cause problems with bleeding in your baby when
it is born.
Your doctor should discuss the possible effects of
Phenobarbital tablets on the unborn child and the risks and
benefits of treatment should be considered carefully.
As with all women, adequate supplements of folic acid
should be taken before conception and during pregnancy.
As Phenobarbital is released into breast milk this may make
your baby sleepy and therefore breast feeding is not


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Driving and using machines
If you feel drowsy after taking this medicine, DO NOT drive
or operate machinery until this effect has worn off.
Phenobarbital tablets contain lactose and colour sunset
yellow (E110)
If you have been told by your doctor that you have an
intolerance to some sugars, contact them before taking this
medicine, as it contains lactose.
The colour sunset yellow (E110) in the 60 mg tablets may
cause allergic-type reactions including asthma.

If you see another doctor or go into hospital or need a blood
or urine test, let them know what medicines you are taking as
Phenobarbital tablets may interfere with the results.

3. How to take Phenobarbital tablets

Always take this medicine exactly as your doctor has told
you. The pharmacist’s label should tell you how much to take
and how often. Check with your doctor if you are not sure.
Swallow the tablets with a glass of water at the same time
each day.
The usual doses are:
Adults - The usual dose is 60 to 180 mg daily taken at night.
Children - If this medicine is prescribed for a child make
sure that the tablets are taken as stated on the pharmacist’s
label. The usual dose is 5 to 8 mg per kg of bodyweight per
Elderly - Your doctor may prescribe a lower dose.

If you take more tablets than you should
If you or anyone else has swallowed a lot of the tablets all
together contact your nearest hospital casualty department or
doctor immediately. Signs of an overdose include drowsiness,
speech problems, jerky movements, and jerky eye
movements, loss of inhibition, reduced reflex response, low
body temperature, low blood pressure and breathing
If you forget to take the tablets
If you forget to take a dose, take it as soon as you remember,
but do not take two doses together. Then go on as before.

If you stop taking the tablets
Do not stop taking the tablets suddenly, if you stop taking the
tablets you may develop withdrawal effects such as
sleeplessness, anxiety, tremor, dizziness, feeling sick, fits and
If you have any further questions on the use of this medicine,
ask your doctor or pharmacist.

4. Possible side effects

Like all medicines, this medicine can cause side effects,
although not everybody gets them.
Serious effects: tell your doctor straight away if the
following happens:
• allergic reaction: skin eruptions, fever, swelling of face,
lips, tongue or throat, or difficulties in breathing or
• blood: reduced numbers and types of blood cells and
platelets (anaemia). If you notice pale skin, weakness or
breathlessness, increased bruising, nosebleeds, sore throats
or infections, you should tell your doctor who may want to
perform a blood test
• liver: inflammation of liver (hepatitis), reduced flow of
bile from the gall bladder (cholestasis), yellowing of your
skin or the whites of your eyes
• skin: rashes, erythema multiforme (circular, irregular red
patches), lumps in the armpits or groin area. Potentially life
threatening skin rashes (Stevens-Johnson syndrome severe skin rashes with flushing, fever, blisters or ulcers
and toxic epidermal necrolysis - severe rash involving
reddening, peeling and swelling of the skin that resembles
severe burns) have been reported very rarely
The following side effects are usually mild and may
disappear with continued treatment. If they are severe or last
longer than a few days you should tell your doctor.

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• nervous system: hyperactivity, behavioural disturbances in

children, unsteady walking, jerky eye movement, visual
disorders, lack of energy, drowsiness
metabolism and nutrition: bone softening and bone
disease (rickets). There have been reports of bone disorders
including osteopenia (thinning of the bones) and
osteoporosis (loss of bone mass) and fractures. Check with
your doctor or pharmacist if you are on long-term
antiepileptic medication, have a history of osteoporosis, or
take steroids
mental health: restlessness and confusion in elderly,
unusual excitement, depression, hallucination (sensing
things that are not real), memory problems, difficulty in
concentrating, changes in behaviour
heart: low blood pressure
lungs: difficulty breathing
kidneys: changes in the amount or need to pass water
anticonvulsant hypersensitivity syndrome characterised by
fever, rash, swollen lymph nodes and other multi-organ

Reporting of side effects
If you get any side effects, talk to your doctor, pharmacist or
nurse. This includes any possible side effects not listed in this
leaflet. You can also report side effects directly via the
Yellow Card Scheme at: By
reporting side effects you can help provide more information
on the safety of this medicine.

5. How to store Phenobarbital tablets

Keep this medicine out of the sight and reach of children.

• Do not use this medicine after the expiry date stated on the

label after ‘EXP’. The expiry date refers to the last day of
that month.
• Do not store above 25°C.
• Keep the container tightly closed.
• Store in the original container.
• The tablets are sensitive to moisture and light.
Do not throw away any medicines via wastewater or
household waste. Ask your pharmacist how to throw away
medicines you no longer use. These measures will help
protect the environment.

6. Contents of the pack and other information

What Phenobarbital tablets contain
The active ingredient is 30mg or 60mg of Phenobarbital.
The other ingredients are maize starch, lactose monohydrate,
sodium lauryl sulphate, sodium starch glycollate, magnesium
stearate and stearic acid. The 60 mg tablets contain the colour
sunset yellow E110.
See end of section 2 for further information on lactose and
colour sunset yellow (E110).
What Phenobarbital tablets look like and contents of the
• Phenobarbital 30mg tablets are white, circular tablets
embossed PV on one side and P over 30 on the other.
• Phenobarbital 60mg tablets are pale orange, circular
tablets embossed PV on one side and P over 60 on the
• Phenobarbital tablets are available in pack sizes of 28 and
1000 tablets.
Not all pack sizes may be marketed.
Marketing Authorisation Holder and Manufacturer:
Pharmvit Ltd, 177 Bilton Road, Perivale,
Greenford, Middlesex UB6 7HQ.
Telephone: 0208 997 5444
0208 997 5433

To request a copy of this leaflet in large print or audio format
or additional copies, please contact the licence holder at the
address (or telephone, fax) above.
PL 4556/0048 & PL 4556/0049
Reference: 0048490415/02

Date leaflet last revised: April 2015


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Further information

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