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Half Sinemet® CR 25mg/100mg Prolonged-Release Tablets
(carbidopa and levodopa)
Your medicine is known by the above name, but will be referred to as
Sinemet CR throughout this leaflet. Sinemet CR is also available in
another strength (50mg/200mg).
Patient Information Leaflet
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 any further questions, 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 Sinemet CR is and what it is used for
2) Before you take Sinemet CR
3) How to take Sinemet CR
4) Possible side effects
5) How to store Sinemet CR
6) Further information

1) What Sinemet CR is and what it is used for
Sinemet CR improves the signs of Parkinson’s disease. Parkinson's
disease is a long-term illness where:
• you become slow and unsteady
• your muscles feel stiff
• you may develop shaking or trembling (called ‘tremor’).
If not treated, Parkinson's disease can make it hard for you to continue
your normal daily activities.
Sinemet CR contains two different medicines called: levodopa and
• levodopa turns into a material called ‘dopamine’ in your brain. The
dopamine helps to improve the signs of your Parkinson’s disease.
• carbidopa belongs to a group of medicines called ‘aromatic amino acid
decarboxylase inhibitors’. It helps levodopa work more effectively by
slowing the speed at which levodopa is broken down in your body.

2) Before you take Sinemet CR
Do not take Sinemet CR if:
• you are allergic (hypersensitive) to carbidopa or levodopa or any of the
other ingredients of Sinemet CR (listed in Section 6)
• you have ever had skin cancer or you have any unusual moles which
have not been examined by your doctor
• you are taking certain medicines called ‘MAOIs’ (Monoamine Oxidase
Inhibitors) used for depression. You need to stop using these medicines
at least two weeks before you start Sinemet CR (see also under ‘Taking
other medicines’ below)
• you have a condition called ‘narrow-angle glaucoma’ that may cause a
sudden build up of pressure in the eye
• you have a severe mental disorder
• you are pregnant, might become pregnant, or are breast-feeding.
Do not take Sinemet CR if any of the above apply to you. If you are not
sure, talk to your doctor or pharmacist before taking Sinemet CR.
Take special care with Sinemet CR
Check with your doctor or pharmacist before taking your medicine if:
• you have a history of fits (convulsions)
• you have had an ulcer in your gut (called ‘duodenal’ or ‘peptic ulcer’) or
have vomited blood
• you have had a heart attack, heart beat problems, circulation or
breathing problems
• you have had kidney, liver or hormonal problems
• you have had depression or other mental problems
• you have a condition called ‘chronic wide-angle glaucoma’ that may
cause a build up of pressure in the eye. You will need to have regular
checks on the pressure in your eye
• you sometimes have sudden sleep attacks or sometimes feel very
• you are due to have surgery.
If you are not sure if any of the above apply to you, talk to your doctor or
pharmacist before taking Sinemet CR.
Tell your doctor if you or your family/carer notices you are developing
urges or cravings to behave in ways that are unusual for you or you cannot
resist the impulse, drive or temptation to carry out certain activities that
could harm yourself or others. These behaviours are called impulse control
disorders and can include addictive gambling, excessive eating or
spending, an abnormally high sex drive or an increase in sexual thoughts
or feelings. Your doctor may need to review your treatments.

Taking other medicines
Please tell your doctor or pharmacist if you are taking or have recently
taken any other medicines, including medicines obtained without a
prescription. This includes herbal medicines. This is because Sinemet CR
can affect the way some other medicines work. Also some other medicines
can affect the way Sinemet CR works.
In particular tell your doctor or pharmacist if you are taking any of the
following medicines:
• Medicines for Parkinson’s disease containing levodopa:
− If they are ‘slow release’, you will need to wait 24 hours after your last
dose before starting Sinemet CR.
− If they are ‘normal release’, you will need to wait 12 hours after your last
dose before starting Sinemet CR.
− Tell the doctor or pharmacist even if you have only taken them in the
Medicines for Parkinson’s disease which do not contain levodopa will
usually be continued. However, your dose may be changed.
• Medicines for mental problems (including depression), tuberculosis (TB),
high blood pressure, muscle spasms, epilepsy or other diseases related
to involuntary movements. Your dose may need to be changed.
• Medicines to treat low iron. Your dose may need to be changed.
• Medicines called ‘MAOIs’ (see also ‘Do not take Sinemet CR if’).
• Anticholinergic medicines (such as orphenadrine, trihexyphenidyl,
benzatropine and procyclidine). Your dose may need to be changed.
• Phenytoin which is used to treat fits (convulsions).
• Papaverine which is used to treat impotence in men.
If you are not sure if any of the above apply to you, talk to your doctor or
pharmacist before taking this medicine. Your doctor or pharmacist has a
more complete list of medicines to avoid while taking Sinemet CR.
Tests while you are taking Sinemet CR
This medication can affect some laboratory tests that your doctor may
perform on blood or urine samples. Please remind your doctor if you are
taking Sinemet CR and are having any tests.
Taking Sinemet CR with food and drink
Try to avoid taking your tablets with a heavy meal. If your diet contains too
much protein (meat, eggs, milk, cheese) Sinemet CR may not work as well
as it should.
Pregnancy and breast-feeding
Do not take Sinemet CR if you are pregnant, might become pregnant or
are breast-feeding. Levodopa, one of the substances in Sinemet CR, is
passed into human milk.
Ask your doctor or pharmacist for advice before taking any medicine, if you
are pregnant or breast-feeding.
Driving and using machines
• Sinemet CR affects different people in different ways. Some people have
side effects which affect their ability to drive or use tools or machines
(see Section 4 Possible side effects). Do not drive or use tools or
machines if you get these effects.
• Sinemet CR can also make you sleepy or cause 'sudden sleep attacks'.
If this happens to you, you must not drive or use tools or machines. Your
doctor will tell you if you can start driving again if these attacks stop.

3) How to take Sinemet CR
Always take Sinemet CR exactly as your doctor has told you. You should
check with your doctor or pharmacist if you are not sure.
Taking this medicine
• Take this medicine by mouth. You must swallow your tablets whole. Do
not break, crush or chew the tablets.
• Although your medicine can have an effect after one day, it may take up
to seven days to work.
• Take them at regular time intervals according to your doctor's
• Do not change the times at which you take your tablets or take any other
medicines for Parkinson's disease without first consulting your doctor.
You should not take Sinemet CR or Half Sinemet CR tablets at intervals
of less than 4 hours apart.
• Try to avoid taking your tablets with a heavy meal.
If you have not had levodopa before
The usual starting dose for Sinemet CR is one tablet twice a day.
If you have had levodopa before
• your doctor will ask you to stop taking your medicine for Parkinson’s
disease for 8 hours before you start taking Sinemet CR.
The usual starting dose for Sinemet CR is one tablet twice a day. Your
doctor may ask you to take Half Sinemet CR to help in determining the
correct dose.

A combination of more than one Sinemet or Sinemet CR product may be
prescribed by your doctor. If you have been given different Sinemet or
Sinemet CR tablets to take make sure that you are taking the correct one
at the right time. Remember: Half Sinemet CR is a lower dose tablet than
Sinemet CR.
Children under 18 years of age
Sinemet CR is not suitable for children under the age of 18 years.
If you take more Sinemet CR than you should
If you take too many tablets see your doctor immediately.
If you forget to take Sinemet CR
Do not take a double dose to make up for a forgotten dose.
If you stop taking Sinemet CR
Do not stop taking Sinemet CR or change your dose without talking to your
doctor first. When you stop taking Sinemet CR the following can occur: stiff
muscles, high temperature (fever) and mental changes.
If you have any further questions on the use of this product, ask your
doctor or pharmacist.

4) Possible side effects
Like all medicines, Sinemet CR can cause side effects, although not
everybody gets them.
Stop taking Sinemet CR and see your doctor straight away, if you
notice any of the following side effects:
• allergic reaction, the signs may include hives (nettle rash), itching, rash,
swelling of your face, lips, tongue or throat. This may cause difficulty in
breathing or swallowing
• chest pain
• uneven (irregular) heart beat or palpitations
• dizziness on standing-up quickly
• bleeding from your gut which may be seen as blood in your faeces or
darkened faeces (gastro-intestinal bleeding)
• blood problems, the signs may include pale skin (pallor), tiredness, fever,
sore throat or mild bruising and prolonged bleeding after injury
• stiff muscles, high fever
• mental changes including delusions, hallucinations and depression
• fits (convulsions).
The most common side effects are
• abnormal movements such as twitching or spasms (which may or may
not be like your Parkinson's symptoms)
• nausea.
Other side effects include
• fainting, anorexia, high blood pressure
• inflammation of the veins, being sick (vomiting), diarrhoea, discoloration
of urine, sweat or saliva
• on-off phenomenon, characteristic of some people with long-standing
Parkinson’s disease. This is when you can have unpredictable changes
from being mobile - “on” - to a sudden inability to move - “off”. “Off” to
“on” can occur just as suddenly
• dizziness; sleepiness (including excessive drowsiness or sudden sleep
onset episodes), pins and needles
• dream abnormalities, confusion, feeling agitated, shortness of breath,
hair loss.
You may experience the following side effects:
• inability to resist the impulse to perform an action that could be harmful,
which may include:
o strong impulse to gamble excessively despite serious personal or
family consequences
o altered or increased sexual interest and behaviour of significant
concern to you or to others, for example, an increased sexual drive
o uncontrollable excessive shopping or spending
o binge eating (eating large amounts of food in a short time period) or
compulsive eating (eating more food than normal and more than is
needed to satisfy your hunger)
Tell your doctor if you experience any of these behaviours; he/she
will discuss ways of managing or reducing the symptoms.
Side effects that have been reported with medicines containing
These may be experienced when taking Sinemet CR.
Nervous system:
• loss of control over the voluntary movements of everyday life
• numbness, increased hand tremor, muscle twitching, muscle cramp,
irregular movement of jaw muscles resulting in difficulty opening the
• difficulty sleeping, feeling anxious or high, falling over and abnormal
walking patterns
• headache

• drooping eyelid and dilated pupil
• changes in vision, irregular movement of the eye
Digestive system:
• indigestion, dry mouth, bitter taste
• swelling of the salivary glands, difficulty swallowing, grinding of the teeth
• hiccups, abdominal pain and distress, constipation, wind
• burning sensation of the tongue
• persistent abnormal erection of the penis
• difficulty passing urine or incontinence (inability to control urine flow)
• changed patches of pigmented skin, including, irritated or irregular
moles, or moles in which you have noticed changes (melanoma)
• weight gain or loss, swelling in the limbs
• flushing, hot flushes, increased sweating
• feeling weak, faint or tired
• hoarseness, general feeling of being unwell
• increased energy or activity, unusual breathing pattern
If any symptoms persist or you experience any other side effects please
tell your doctor or pharmacist. It will help if you make a note of what you
experienced, when it started and how long it lasted.
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 Sinemet CR
• Keep out of the sight and reach of children.
• Do not store above 30°C. Store in the original package in order to protect
from light.
• Do not take Sinemet CR after the expiry date printed on the carton label
or blister strip. The expiry date refers to the last day of the month.
• If the tablets become discoloured or show any other signs of
deterioration, you should seek the advice of your pharmacist who will tell
you what to do.
• Medicines should not be disposed of via wastewater or household waste.
Ask your pharmacist how to dispose of medicines no longer required.
These measures will help to protect the environment.

6) Further information
What Sinemet CR contains:
Each tablet contains carbidopa equivalent to 25mg anhydrous carbidopa
and levodopa 100mg in a modified release formulation.
The other ingredients are:
Hydroxypropyl cellulose, magnesium stearate, poly (vinyl acetate-crotonic
acid) copolymer and red iron oxide (E172).
What Sinemet CR looks like and contents of the pack
Each Sinemet CR tablet is a pink, oval-shaped, biconvex tablets, marked
'601' on one side and plain on the other.
Sinemet CR tablets are available as blister packs of 50 tablets.
PL 10383/2189

Half Sinemet CR 25mg/100mg
Prolonged-Release Tablets

Who makes and repackages your medicine?
Your medicine is manufactured by Merck Sharp and Dohme B.V.,
Waarderweg 39, 2031 BN – Haarlem, The Netherlands. Procured from
within the EU and repackaged by Product Licence Holder: Primecrown Ltd,
4/5 Northolt Trading Estate, Belvue Road, Northolt, Middlesex, UB5 5QS.
Leaflet date: 16.08.2016
Sinemet is a registerted trademark of Merck Sharp & Dohme Corp., USA.

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Further information

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