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Phenytoin Injection BP
Read all of this leaflet carefully
before you start using this
• Keep this leaflet. You may need
to read it again.
• If you have any further questions,
ask your doctor or pharmacist.
• If any of the side effects gets
serious, or if you notice any side
effects not listed in this leaflet,
please tell your doctor.
In this leaflet:
1. What Phenytoin Injection is and what
it is used for
2. Before Phenytoin Injection is used
3. How Phenytoin Injection is used
4. Possible side effects
5. How Phenytoin Injection is stored
6. Further information


Phenytoin is one of a group of
medicines called hydantoins.
Phenytoin Injection is a medicine which
is used to control status epilepticus
(serious condition in which seizures
(fits) continue for hours or days) or to
prevent fits during or after neurosurgery.
It can also be used to correct some
heart rhythm abnormalities.


Phenytoin Injection should not be
• if you have shown signs of
hypersensitivity (severe allergy) to
phenytoin or medicines of the same
class (hydantoins) in the past
• in patients with certain heart
If possible, tell your doctor if any of
the above applies to you before this
medicine is used.
This medicine must not be injected into
an artery. See section 3 for the correct
method of administration.

Take special care with Phenytoin
A small number of people being treated
with anti-epileptics such as phenytoin
have had thoughts of harming or killing
themselves. If at any time you have
these thoughts, immediately contact
your doctor.
Serious skin side effects can rarely
occur during treatment with Phenytoin
Injection. This risk may be associated
with a variant in genes in a subject
of Chinese or Thai origin. If you are
of such origin and have been tested
positively carrying this genetic variant
(HLA-B*1502), discuss this with
your doctor before taking Phenytoin

Special care needs to be taken with
Phenytoin Injection
• if you have a liver or kidney disorder
• if you suffer from diabetes
If possible, tell your doctor if any of
the above applies to you before this
medicine is used.

Taking/using other medicines
Special care is needed if you are taking/
using other medicines as some could
interact with phenytoin, for example:
• some antibacterials i.e. doxycycline,
ciprofloxacin, chloramphenicol,

Phenytoin Injection BP
The following information is intended
for medical or healthcare professionals
Practical information on the preparation/
handling of the medicinal product is
provided here.
Intra-arterial administration must be
avoided in view of the high pH of the

isoniazid, rifampicin, and other
some antifungals i.e. ketoconazole,
fluconazole, miconazole
some coumarin anticoagulants, e.g.
medicines used to control diabetes
e.g. insulin or oral anti-diabetic
some pain killers and
anti-inflammatory medicines, i.e.
phenylbutazone and salicylates such
as aspirin
some medicines used to control
anxiety, i.e. chlordiazepoxide,
barbiturates, e.g. phenobarbitone
and amylobarbitone
corticosteroids (used in numerous
situations to aid the body’s healing
some medicines used to treat
mental problems such as psychoses
and depression, e.g. haloperidol,
methylphenidate, monoamine
oxidase inhibitors, trazodone,
thioxanthenes and tricyclic
oral contraceptives and other
medicines which mimic female
hormones, e.g. oestrogen and
antiepileptic medicines, e.g.
carbamazepine, ethosuximide,
mephenytoin, primidone, sodium
valproate, sulthiame, valproic acid
and trimethadione
halothane (an inhaled general
some anti-ulcer medicines, i.e.
cimetidine and ranitidine
medicines taken to help the heart,
i.e. aspirin, beta-blockers, diazoxide,
digoxin, disopyramide, dopamine,
frusemide, mexiletine, nifedipine,
quinidine, reserpine and verapamil
medicines often taken while
undergoing cancer treatment,
i.e. bleomycin, calcium folinate,
carboplatin, carmustine, cisplatin,
dacarbazine and vinblastine
St John’s wort - The herbal
remedy 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 preparations
others which you may recognise
by name: ciclosporin, disulfiram,
folic acid, L-dopa, lignocaine,
succinimide, theophylline (a
xanthine), methotrexate and
vitamin D

If possible, please tell your doctor if you
are taking or have recently taken any
other medicines, including medicines
obtained without a prescription.

Phenytoin and alcohol consumption
The consumption of alcohol, whilst you
are being treated with phenytoin can
reduce the effectiveness of treatment or
increase the side effects.

Pregnancy and breast-feeding
If possible, tell your doctor if you are
pregnant, trying to become pregnant or
breast-feeding. Your doctor will only use
this medicine if the expected benefits
outweigh any potential risk to your baby.
Ask your doctor or pharmacist for
advice before taking any medicine.

Driving and using machines
Do not drive or use machines if you
experience any side effect (e.g.
dizziness or drowsiness) which may
lessen your ability to do so.

Important information about some
of the ingredients of Phenytoin
This medicinal product contains 10% vol
ethanol (alcohol), i.e. up to 1.6 g per 1 g
dose of phenytoin, equivalent to 57 ml
of a 3.5% vol beer or 14 ml of a 14% vol

Incompatible with amikacin sulphate,
cephapirin sodium, clindamycin phosphate,
and many other drugs. It is recommended
that phenytoin sodium is not mixed with
other drugs or with any infusion solution
other than sodium chloride 0.9%.

Instructions for use and handling
For single use. Discard any unused


wine. Harmful to those suffering from
alcoholism. To be taken into account
in pregnant or breast-feeding women,
children and high-risk groups such as
patients with liver disease or epilepsy.
In addition, this medicinal product
contains propylene glycol, which can
cause alcohol-like symptoms.

This medicine will be given to you by
a slow injection via a drip into a vein
or, more rarely, via an injection into a

Your doctor will calculate the correct
does of phenytoin for you.
The dose will depend upon your
medical condition, your size, your age
and how well your kidneys, liver and
heart are working. Your doctor will tell
how well your liver and kidneys are
working from blood and urine samples.
Where treatment is prolonged, blood
samples may be taken to check
the level of phenytoin in the blood.
Subsequent doses may be increased or
decreased accordingly.

If you are given too much or too little
Phenytoin Injection
As this medicine will be given to you
whilst you are in hospital it is unlikely
that you will be given too little or too
much, however tell your doctor or
pharmacist if you have any concerns.

Effects when treatment with
phenytoin is stopped
Sudden withdrawal of phenytoin
treatment in patients susceptible to fits
may cause status epilepticus. In such
cases, phenytoin dosage reduction
should be gradual, perhaps following a
switch to a form of phenytoin which can
be taken by mouth.

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

If any of the following happen, tell
your doctor immediately:
• severe allergic reaction - you may
experience a sudden itchy rash
(hives), swelling of the hands, feet,
ankles, face, lips, mouth or throat
(which may cause difficulty in
swallowing or breathing), and you
may feel you are going to faint
• rash (can be severe resulting in
painful reddening and blistering of
the skin, eyes, inside of the mouth
and ano-genital region and may lead
to skin shedding)
• swollen lymph nodes (isolated small
raised lumps under the skin)
• chest pains and palpitations
These are serious side effects. You may
need urgent medical attention.

If any of the following happen, tell
your doctor as soon as possible:
• pain and inflammation at the injection
site (in rare instances severe tissue
damage has required amputation)
• tightness of the chest or wheezing
• dizziness/fainting
• fever
• persistent pain, tingling or numbness
• slurred speech
• muscle twitching and/or rapid
uncontrollable eye movements
• difficulties associated with muscular
movement: loss of muscle
co-ordination, clumsiness or
unsteadiness, shaking and loss of
muscle tone
• bleeding, tender or enlarged gums
(may be reduced by maintaining
good oral hygiene and massaging
the gums)
The product should be visually inspected
for particulate matter and discolouration
prior to administration.
Phenytoin Injection is suitable for use as
long as it remains free of haziness and
precipitate. A precipitate might form if the
product has been kept in a refrigerator
or freezer. This precipitate will dissolve if
allowed to stand at room temperature. The
product will then be suitable for use.
For infusion administration, Phenytoin

joint pain
yellowing of the eyes and skin
enlargement of facial features
including thickening of the lips
unusual and excessive hair growth
on body and face
Peyronie’s disease (a condition
where male patients experience a
deformation of the penis which may
cause pain when the penis is erect)
unusual tiredness or weakness
a feeling of nervousness
loss of appetite and weight

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.
Phenytoin may cause problems with
breathing, blood pressure, heart and
liver function and blood cell count. Your
doctor may do tests to check for these
side effects.
If any of the side effects gets serious,
or if you notice any side effects not
listed in this leaflet, please tell your

Keep out of the reach and sight of

This medicine must not be used after
the expiry date which is stated on the
ampoule and carton after 'EXP'. Where
only a month and year is stated, the
expiry date refers to the last day of that

The ampoules should be kept in the
outer carton, in order to protect from
light, and stored at, or below, 25°C.
Unused portions of opened ampoules
must not be stored for later use.

Visible signs of deterioration
Only clear, colourless solutions should
be used. Opaque, cloudy or discoloured
solutions should not be used.

What Phenytoin Injection contains
The active substance is phenytoin
sodium. Each millilitre (ml) of solution
contains 50 milligrams (mg) of
phenytoin sodium.
The other ingredients are ethanol,
propylene glycol and Water for
Injections. See section 2 ‘Important
information about some of the
ingredients of Phenytoin Injection’ for
further information about ethanol and
propylene glycol.

What Phenytoin Injection looks like
and contents of the pack
Phenytoin Injection is a clear, colourless
solution for injection which comes in
glass containers called ampoules.
It is supplied in packs containing
5 x 250 mg/5 ml ampoules.

Marketing authorisation holder and
Hospira UK Limited, Queensway,
Royal Leamington Spa, Warwickshire,
CV31 3RW, UK
This leaflet was last approved in 11/2012

Injection should be diluted in 50 - 100 ml of
normal saline, with the final concentration
of phenytoin in the solution not exceeding
10 mg/ml. Administration should commence
immediately after the mixture has been
prepared and must be completed within
one hour (the infusion mixture should not
be refrigerated). An in-line filter (0.22 0.50 microns) should be used. The diluted
form is suitable for use as long as it
remains free of haziness and precipitate.

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Source: Medicines and Healthcare Products Regulatory Agency

Disclaimer: Every effort has been made to ensure that the information provided here is accurate, up-to-date and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. This information has been compiled for use by healthcare practitioners and consumers in the United States. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective or appropriate for any given patient. If you have questions about the substances you are taking, check with your doctor, nurse or pharmacist.