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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 Pentazocine is and what it is used for.
2. Before you take Pentazocine.
3. How to take Pentazocine.
4. Possible side effects.
5. How to store Pentazocine.
6. Further information.
Pentazocine belongs to a group of medicines
called opioid analgesics. These are strong pain
killers that are used to relieve moderate to
severe pain.
Do not take Pentazocine if you:
• are allergic (hypersensitive) to pentazocine, or
any of the ingredients of this medicine (see
other ingredients)
• have breathing problems for example chronic
bronchitis or asthma
• have a history of alcohol abuse
• you are recovering from a head injury, or you
have a condition which causes increased
pressure on the brain. Symptoms include severe
headaches, being sick, drowsiness or
blurred vision
• have heart failure or suffer from breathlessness
and swollen ankles.
Take special care with Pentazocine - You should
tell your doctor before taking this medicine
if you:
• or one of your family suffer from porphyria
(a metabolic disease)
• are taking a monoamine oxidase inhibitor
(MAOI, a medicine used for depression
e.g. Phenelzine, Isocarboxazid) or you have
• have a rare tumour of the adrenal glands called
a phaeochromocytoma. This causes symptoms
such as headaches, sweating, palpitations,
flushing of the face and pains in the chest
or stomach

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 or the following:
• other strong pain killers (e.g. Morphine,
Diamorphine, Naloxone)
• phenothiazines (used to treat mental disorders,
e.g. Chlorpromazine, Thioridazine)
• monoamine oxidase inhibitors (see above under
'Take special care with Pentazocine')
• Doxapram (used to stimulate breathing).
Pregnancy and breast-feeding - You should not
take Pentazocine if you are pregnant or think you
could be pregnant, or are breast-feeding. Ask your
doctor or pharmacist for advice before taking
any medicine.
Taking Pentazocine with food and drink Do not drink alcohol whilst taking this medicine.
Driving and using machines - Pentazocine may
cause sedation. If affected you should not drive or
use machines.
The medicine can affect your ability to drive as it
may make you sleepy or dizzy.
• Do not drive while taking this medicine until you
know how it affects you.
• It is an offence to drive if this medicine affects
your ability to drive.
However, you would not be committing an
offence if:
• The medicine has been prescribed to treat a
medical or dental problem and
• You have taken it according to the instructions
given by the prescriber or in the information
provided with the medicine and
• It was not affecting your ability to drive safely


(pentazocine HCL)

• have recently had a heart attack
• have high blood pressure
• have kidney or liver disease, or you are elderly.
You may need a lower dose
• have epilepsy
• have a history of drug abuse, or you are
addicted to opiate pain killers such as Morphine
or Diamorphine
• are being treated for an underactive
thyroid gland
• have a condition which affects your
adrenal glands
• have an enlarged prostate gland
• suffer from an inflamed bowel or other
gut disorders
• are a smoker, the effect of Pentazocine may
be decreased.

Talk to your doctor or pharmacist if you are not
sure whether it is safe for you to drive while taking
this medicine.


Always take Pentazocine exactly as your doctor
pharmacist if you are not sure. Swallow the
capsules whole with a full glass of water. The
capsules should be taken after meals. Do not chew
or crush the capsules. Your doctor will decide
how much Pentazocine you should take. This will
depend on your condition and the severity of
your pain.


The usual dose is: Adults capsules every three to four hours. If more pain
relief is needed your doctor may increase your
dose. You should not need to take more than
Children of this medicine for the treatment of children. This
Elderly or patients with kidney or liver problems Your doctor may give you a lower dose.
If you take more Pentazocine than you should Contact your doctor or nearest hospital
emergency department immediately. Take the
container and any remaining capsules with you.
Symptoms of overdose include somnolence,
shallow breathing, low blood pressure, coma
or fits.
If you forget to take Pentazocine - Just take the
next dose at the usual time. Do not try to make up
for the missed dose and do not take two doses
at once.
If you stop taking Pentazocine - Do not
capsules more often or for longer than your
doctor advises. Too much Pentazocine can be
habit forming. This is called dependence. If you
stop taking your medicine suddenly it can cause
symptoms such as sweating, fever, weakness
and muscular pains. Your doctor will stop your
medicine gradually to avoid you having these
withdrawal symptoms.
If you have any further questions on the use of
this product, ask your doctor or pharmacist.
Like all medicines, Pentazocine can cause side
effects, although not everybody gets them. If they
occur, they are likely to be mild. However, some
may be serious and need medical attention.
If the following side effects occur, stop taking the
capsules immediately and contact your doctor:
• sore throat, fever, severe chills and mouth ulcers.
This can be due to a lack of white blood cells
called granulocytes (agranulocytosis)
• fever
• a serious skin reaction called toxic epidermal
necrolysis. This is rare, symptoms include loss of
the outer layers of skin and reddening of the skin.

Other possible side effects are: • light-headedness,
dizziness • feeling sick, vomiting, constipation
• feeling drowsy • sweating • headache • dry mouth
• pins and needles • biliary tract spasm causing
abdominal spasms • urinary retention (difficulty
passing water) • itching or flushing of the skin
• rapid heartbeat • increased pressure on the brain
• slow or shallow breathing • low blood pressure
• short-lived hypertension (high blood pressure)
• altered contractions of the womb
• muscle tremor • mood changes, difficulties
sleeping, nightmares, thought disturbances,
disorientation, hallucinations (sensing things that
are not real e.g. seeing things) • eyesight changes
• blood changes such as a reduction in white blood
cells which makes infections more likely • chills and
allergic reactions.
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.
Keep out of the reach and sight of children. Store
your capsules in a dry place below 25°C. Protect
from light. Do not use pentazocine after the expiry
date which is stated on the container after 'EXP'.
The expiry date refers to the last day of that month.
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.
What Pentazocine Capsules contain ingredients are microcrystalline cellulose,
pregelatinised maize starch, calcium hydrogen
phosphate, sodium metabisulphite, sodium lauryl
sulphate, colloidal silicon dioxide, magnesium
stearate, croscarmellose sodium. The capsule shell
contains yellow iron oxide (E172), red iron oxide
(E172), titanium dioxide (E171), black iron oxide
(E172) and Gelatine. The printing ink also contains
Shellac glaze (modified) in Ethanol, Titanium
Dioxide, Isopropyl Alcohol, N-Butyl Alcohol NF and
Propylene Glycol.
What Pentazocine Capsules look like and
contents of the pack - Your medicine comes as a
capsule. Pentazocine is available in containers or
blister packs of 5, 7, 10, 14, 15, 20, 21, 25, 28, 30, 56,
60, 84, 90, 100, 112, 120, 168, 180, and 500
capsules. Not all pack sizes may be marketed.
Marketing Authorisation Holder: Mylan, Potters Bar,
Manufacturer: Generics [UK] Limited, Potters Bar,
McDermott Laboratories Ltd t/a Gerard Laboratories,
Dublin 13, Ireland.
This leaflet was last approved
in: June 2014




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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.