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Physeptone Mixture SF
Methadone Hydrochloride
(This medicine will be referred to as Physeptone Mixture SF
in this leaflet)
Read all this leaflet carefully before you take
Physeptone Mixture SF
• Keep this leaflet. You may need to read it again
• If you have any further questions, please ask your
doctor or pharmacist
• This medicine has been prescribed for you personally
and you should 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 get serious, or if you notice any
side effects not listed in this leaflet, please tell your
doctor or pharmacist

In this leaflet:

What Physeptone Mixture SF is and what it is used for
Before you take Physeptone Mixture SF
How to take Physeptone Mixture SF
Possible side effects
Storing Physeptone Mixture SF
Further information

This leaflet contains a summary of the information available
for this medicine. You should ask your doctor or pharmacist
if you are unsure about any aspect of this medicine.

1. What Physeptone Mixture SF is and what
it is used for
The active ingredient of this medicine, Methadone
Hydrochloride, is a synthetic opiate (a morphine-like drug)
used in the treatment of addiction in order to reduce
withdrawal symptoms.

2. Before you take Physeptone Mixture SF
Do not take Physeptone Mixture SF if:
• you are allergic (hypersensitive) to methadone or any of
the ingredients of this medicine (listed in section 6)
• you have a head injury and the pressure inside your
brain is higher than it should be (check this with your
doctor). You might be getting bad headaches
• you are suffering from alcoholism
• you are in labour
• you are taking, or have recently stopped taking, a type of
medicine called Monoamine Oxidase Inhibitors (MAOIs)
which are used to treat depression
• you are at risk of developing an obstruction of the
• you have any problems with your breathing or any
chronic lung disease
• you are having an asthma attack. Do not take your dose
until you have completely recovered.
Physeptone Mixture SF is not suitable for children.
Take special care with Physeptone Mixture SF
Tell your doctor if:
• you have history of asthma or breathing difficulties
• you have bowel problems
• you have liver or kidney problems
• you have a history of convulsions, fits or epilepsy

• you have a history of low blood pressure
• you have a history of under-active thyroid gland, or
problems with your adrenal glands
• you have a history of enlarged prostate gland
• you have condition that causes severe muscle weakness
and fatigue (myasthenia gravis)
• you are in shock.
If any of the conditions above apply to you, please consult
your doctor.
Methadone may affect the electrical signals which control
your heart contractions, particularly at high doses.
Tell your doctor if:
• you have a history of heart problems
• you have liver disease
• you have any blood abnormalities such as low levels of
potassium or magnesium
• you have a history of sudden death in the family.
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.
Tell your doctor if you are taking any of the following:
• medicines used to treat addiction e.g. naltrexone and
• cimetidine (a medicine used to treat stomach ulcers)
• drugs used to treat epilepsy (e.g. phenytoin and
• naloxone (a medicine used to treat an overdose of opioid
• antibiotics (medicines used to treat bacterial infections)
• antifungals (medicines used to treat fungal infections)
• medicines that make urine more acidic e.g. ammonium
• antiviral drugs including some medicines used to treat
HIV e.g. nevirapine, zidovudine, efavirenz, nelfinavir,
ritonavir and abacavir
• metoclopramide or domperidone (medicines used to
stop you feeling and being sick)
• mexiletine (a drug used to treat heart irregularities)
• medicines used to treat depression including
fluvoxamine, tricyclic antidepressants such as
amitriptyline and imipramine, or MAOIs including
• CNS depressants (medicines that act on the brain and
cause drowsiness or sleepiness)
• other opioid type drugs e.g. morphine
• pentazocine (a pain killer)
• medicines used to help you relax (tranquillisers)
• medicines used to help you to sleep (sedatives).
Other medicines you may be taking can also affect the
heart. You must tell your doctor about any other medicines
that you are taking as they may be dangerous if they are
taken with methadone. In these situations your doctor may
decide that it is necessary to monitor your heart with an
electrocardiogram (ECG) at the start of treatment to ensure
that these effects do not occur.
Continued overleaf

Taking Physeptone Mixture SF with food and drink You
must not drink alcohol whilst you are taking Physeptone
Mixture SF as this could cause serious side effects.
Pregnancy, breast-feeding and labour
Physeptone Mixture SF should not be taken during labour. If
you are pregnant or breast-feeding you should discuss this
with your doctor before taking Physeptone Mixture SF.
Driving and using machinery
The ability to drive or use machinery may be severely
affected during and after treatment with methadone. You
must not drive or use machinery until you are told that you
can do so by your doctor.
Important information about some of the ingredients
Physeptone Mixture SF contains:
• Colouring agent E110 which may cause an allergic

3. How to take Physeptone Mixture SF
You must only take Physeptone Mixture SF by mouth. Under
no circumstances should you inject this product as injection
may cause serious and permanent damage to your body
with possibly fatal consequences.
Your doctor will tell you how much Physeptone Mixture SF
you need to take, and how often you need to take it. It is
important that you do not take more than the dose agreed
with your doctor. You can become dependant on
Physeptone Mixture SF.
The usual initial dose is 10-20mg a day. The dose will be
slowly increased until you show no signs of withdrawal or
Elderly or ill:
If you are elderly or ill, your doctor will only prescribe
repeated doses with caution.
Not recommended. There is a serious risk of poisoning.
Remember to keep your medicine safely where children can
not get it.
If you forget to take Physeptone Mixture SF
During a course of treatment it is important that, should
you miss a dose, you take the dose as soon as you
remember. However, if it is almost time for you to take your
next dose, miss the dose and wait until the next scheduled
If you take more Physeptone Mixture SF than you
If you take too much Physeptone Mixture SF, you can
experience the following:
• difficulty in breathing
• extreme sleepiness, fainting or coma
• pin point pupils
• muscle weakness
• cold and clammy skin
• slow heartbeat, low blood pressure, heart attack or
shock. in severe cases death may occur.

4. Possible side effects
Like all medicines, Physeptone Mixture SF can cause side
effects, though not everybody gets them.
Side effects which may occur include:
• dizziness (including vertigo), drowsiness, hallucinations
• nausea (feeling sick) or vomiting (being sick),
constipation, a dry mouth
• headaches, raised pressure in the brain
• rashes or itching
• sweating
• reduced blood pressure (you may feel dizzy on standing
• pin point pupils
• confusion, mood changes
• fast or slow beating of the heart, a feeling of trembling in
the heart
• facial flushing
• spasms of the tubes from the gall bladder or urinary
• difficulty in passing water
• a reduction in sex drive
• a reduction in body temperature
• dependence on methadone.
If any of the side effects get serious or you notice side effects
not listed in this leaflet please contact your doctor or pharmacist.

5. Storing Physeptone Mixture SF
Keep out of the reach and sight of children.
This product has an expiry date on the bottle label. This will
have been checked by your pharmacist or doctor. If you have a
product that has passed the given expiry date, return it to your
pharmacist or doctor for safe disposal. Once you have opened
the bottle you are advised to dispose of it after 4 weeks.
Store below 25°C.

6. Further information
What Physeptone Mixture SF contains:
The active ingredient is Methadone Hydrochloride 1mg in 1ml.
The other ingredients are Lycasin(r) 80/55, potassium
sorbate, purified water and colours E110 (sunset yellow
FCF), E142 (green S) and quinoline yellow.
What Physeptone Mixture SF looks like and the contents
of the pack:
Physeptone Mixture SF is a bright green liquid, supplied in
amber glass bottles, each containing 500, 100, 50 or 30ml of
the solution.
Marketing Authorisation Holder and Manufacturer:
Martindale Pharmaceuticals, Bampton Road, Harold Hill,
Essex RM3 8UG, UK
Product licence number:
PL 00156/0030
Date of last Revision:
© Martindale Pharmaceuticals
If this leaflet is difficult to see or read, please contact the
marketing authorisation holder for help.


In the event of overdose you should seek medical assistance
immediately even if you feel well as you may be suffering
methadone poisoning.

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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.