Active substance: METRONIDAZOLE

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200MG AND 400MG

Read all of this leaflet carefully before you start
taking this medicine.
• Keep this leaflet. You may need to read it again.
• If you have further questions, please ask your doctor
or pharmacist.
• This medicine has been prescribed for you. Do not
pass it on to others. It may harm them, even if their
symptoms are the same as yours.
• If any of the side effects gets serious, or if you
notice any side effects not listed in this leaflet,
please tell your doctor or pharmacist.
In this leaflet:
1. What Flagyl is and what it is used for
2. Before you take Flagyl
3. How to take Flagyl
4. Possible side effects
5. How to store Flagyl
6. Further information
The name of this medicine is Flagyl 200mg or 400mg
Tablets (called Flagyl in this leaflet). Flagyl contains a
medicine called metronidazole. This belongs to a group
of medicines called antibiotics.
It works by killing bacteria and parasites that cause
infections in your body.
It can be used to:
• Treat infections of the blood, brain, lung, bones,
genital tract, pelvic area, stomach and intestines
• Treat gum ulcers and other dental infections
• Treat infected leg ulcers and pressure sores
• Prevent infections after surgery
If you need any further information on your illness,
speak to your doctor.
Do not take Flagyl and tell your doctor if:
• You are allergic (hypersensitive) to metronidazole,
nitroimidazoles (e.g. tinidazole) or any of the other
ingredients in your medicine (listed in Section 6:
Further information).
Signs of an allergic reaction include: a rash,
swallowing or breathing problems, swelling of your
lips, face, throat or tongue.
Do not take Flagyl if any of the above apply to you. If
you are not sure, talk to your doctor or pharmacist
before taking Flagyl.
Take special care with Flagyl and check with your
doctor or pharmacist before using your medicine if:
• You have or have ever had a liver problem.
• You are having kidney dialysis (see section 3:
‘People having kidney dialysis’)
• You have a disease of the nervous system
If you are not sure if any of the above apply to you, talk
to your doctor or pharmacist before taking your
medicine. Do this even if they have applied in the past.
Taking other medicines
Please tell your doctor or pharmacist if you are taking or
have recently taken any other medicines. This includes
medicines obtained without a prescription, including
herbal medicines. This is because Flagyl can affect the
way some other medicines work. Also, some other
medicines can affect the way Flagyl works.

In particular tell your doctor if you are taking any of the
following medicines:
• Medicines used to thin the blood such as warfarin
• Lithium for mental illness
• Phenobarbital or phenytoin for epilepsy
• 5 fluorouracil for cancer
• Busulfan for leukaemia (cancer of the blood cells)
• Ciclosporin – to prevent the rejection of organs after
• Disulfiram for alcoholism
If you are not sure, talk to your doctor or pharmacist
before taking Flagyl.
Taking Flagyl with food and drink
Do not drink any alcohol while you are taking Flagyl and
for 48 hours after finishing your course. Drinking alcohol
while using Flagyl might cause unpleasant side effects,
such as feeling sick (nausea), being sick (vomiting),
stomach pain, hot flushes, very fast or uneven
heartbeat (palpitations) and headache.
Pregnancy and breast-feeding
Tell your doctor before using Flagyl if:
• You are pregnant, might become pregnant or think you
may be pregnant. Flagyl should not be taken during
pregnancy unless considered absolutely necessary.
• You are breast-feeding. It is better not to use Flagyl
if you are breast-feeding. This is because small
amounts may pass into the mother’s milk.
Driving and using machines
While taking Flagyl you may feel sleepy, dizzy, confused,
see or hear things that are not there (hallucinations),
have fits (convulsions) or temporary eyesight problems
(such as blurred or double vision). If this happens, do not
drive or use any machinery or tools.
Your doctor may wish to carry out some tests if you
have been using this medicine for more than 10 days.

Taking your medicine
Always take Flagyl exactly as your doctor has told you.
It is important to finish a full course of treatment. The
length of a course will depend on your needs and the
illness being treated.
Check with your doctor or pharmacist if you are not
• Swallow the tablets whole with a drink of water
• Do not crush or chew the tablets
• Take these tablets during or just after a meal
• The dose of Flagyl will depend on your needs and
the illness being treated
• The length of your treatment will depend on the type
of illness you have and how bad it is
The usual dose for adults and children is given below:
To treat bacterial infection
• The initial dose is 800mg
• After 8 hours take another dose of 400mg and
repeat this dose every 8 hours
• Your doctor will work out how much your child
should take depending on their weight
• Repeat the dose every 8 hours
• If your child is a baby under 8 weeks of age, your
doctor will give them one daily dose or two
separate doses 12 hourly

To prevent infections from happening after surgery
• Start Taking Flagyl Tablets 24 hours before your
• Take 400 mg of Flagyl every 8 hours
• After the operation you may be given Flagyl either
through a drip into a vein or rectally as a
suppository until you are able to take tablets again
• Give your child Flagyl Tablets 1-2 hours before
their operation
• Your doctor will work out how much your child
should take depending on their weight
• After the operation your child may be given
Flagyl either through a drip into a vein or rectally
as a suppository until they are able to take
tablets again
Other types of infections
For treatment of other infections caused by parasites
and some bacteria your doctor will decide how much
Flagyl you need to take and how often. This will depend
on your illness and how bad it is. The pharmacist’s label
on the packaging will tell you how many tablets to take
and how often to take them.
People having kidney dialysis
Kidney dialysis removes Flagyl from your blood. If you
are having kidney dialysis you must take this medicine
after your dialysis treatment.
People with liver problems
Your doctor may tell you to use a lower dose or to use
the medicine less often.
If you take more Flagyl than you should
If you take more Flagyl than you should, tell your doctor
or go to your nearest hospital casualty department
straight away. Take the pack and any tablets left with
you. This is so the doctor knows what you have taken.
If you forget to take Flagyl
If you forget to take Flagyl, take it as soon as you
remember. However, if it is almost time for your next
dose, skip the missed dose. Do not use a double dose
to make up for a forgotten dose.
Like all medicines, Flagyl can cause side effects,
although not everybody gets them.
Stop taking Flagyl and see a doctor or go to a
hospital straight away if:
• You get swelling of the hands, feet, ankles, face, lips
or throat which may cause difficulty in swallowing or
breathing. You could also notice an itchy, lumpy
rash (hives) or nettle rash (urticaria)
This may mean you are having an allergic reaction
to Flagyl.
• A serious but very rare side effect is a brain
disease (encephalopathy).
Symptoms vary but you might get a fever, stiff
neck, headache, see or hear things that aren’t there.
You might also have problems using your arms
and legs, problems with speaking or feel confused.
Talk to your doctor straight away if you notice the
following side effects.
• Yellowing of the skin and eyes. This could be due to
a liver problem (jaundice).
• Unexpected infections, mouth ulcers, bruising,
bleeding gums, or severe tiredness. This could be
caused by a blood problem.
• Severe stomach pain which may reach through to
your back (pancreatitis)
Tell your doctor or pharmacist if you notice any of
the following side effects:
Very rare (affects less than 1 in 10 000 people)

• Fits (convulsions)
• Mental problems such as feeling confused and
seeing or hearing things that are not there
• Problems with your eyesight such as blurred or
double vision
• Skin rash or flushing
• Headache
• Darkening of the urine
• Feeling sleepy or dizzy
• Pains in the muscles or joints
• Liver problems including life-threatening liver failure
(hepatocellular liver injury)
Not known (frequency cannot be estimated from the
available data)
• Numbness, tingling, pain, or a feeling of weakness,
in the arms or legs
• Unpleasant taste in the mouth
• Furred tongue
• Feeling sick (nausea), being sick (vomiting), upset
stomach, stomach pain or diarrhoea
• Loss of appetite
• Fever
• Feeling depressed
• Pain in your eyes (optic neuritis)
• A group of symptoms together including: fever,
nausea, vomiting, headache, stiff neck and
extreme sensitivity to bright light. This may be
caused by an inflammation of the membranes
that cover the brain and spinal cord (meningitis)
If any of the side effects gets serious, lasts longer than
a few days or you notice any side effects not listed in
this leaflet, please tell your doctor or pharmacist.
• Keep your medicine in a safe place and out of the
reach and sight of children.
• Store below 30º C in the original packaging (protect
from light)
• Do not use this medicine after the expiry date shown
on the pack.
• Ask your pharmacist how to dispose of medicines
no longer required. Do not dispose of medicines
by flushing down a toilet or sink or by throwing
out with your normal household rubbish. This will
help protect the environment.
What Flagyl Tablets contain
Each tablet contains 200mg or 400mg of metronidazole
as the active substance.
Other ingredients are: calcium hydrogen phosphate
(E341), starch maize, povidone K30 (E1201) and
magnesium stearate.
The coating of the tablets contains: Pharmacoat 615
(E464) and Macrogol 400.
What Flagyl Tablets look like and contents of the pack
Flagyl 200mg and 400mg Tablets are white to off-white
biconvex film coated tablets with ‘Flagyl 200’ or ‘Flagyl
400’ printed on one side.
Flagyl 200mg Tablets are available in aluminium/plastic
blister packs of 21 tablets and HDPE bottles of 100 and
250 tablets.
Flagyl 400mg Tablets are available in aluminium/plastic
blister packs of 14 tablets and HDPE bottles of 100
The Marketing Authorisation Holder is:
Zentiva, One Onslow Street, Guildford,
Surrey, GU1 4YS, UK
The Manufacturer is: Famar Health Care Services
Madrid, S.A.U., Avda. Leganés, 62,Alcorcón 28923
(Madrid) Spain
This leaflet was last updated in January 2013
“Flagyl” and “Zentiva” are registered trademarks.
©2013 Zentiva.

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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.