Pentazocine - oral

Patient Medicine Information
Why do I need this medicine?
Pentazocine is strong painkiller. It is used to relieve moderate to severe pain.
How do I take this medicine?
Take Pentazocine exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.

Take it together with food or immediately after a meal. Try to take it at the same time each day.

Pentazocine is available as a tablet or capsule. Do not divide, chew, or crush the tablet/capsule.

The dose of this medicine will be decided by your doctor. Your doctor will advise you on the treatment timeframe depending on the type and severity of your condition.

Pentazocine must be taken regularly for it to be effective. Do not stop taking it suddenly as this may worsen your condition.
What should I do if I have forgotten to take this medicine?
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.

DO NOT double a dose under any circumstances.

If you often forget to take your medicine, let your doctor and pharmacist know.
When should I not use this medicine?
Alert your doctor if you have the following conditions:
  • lung disease
  • paralytic ileus (bowel obstruction caused by slow movement or paralysis of the intestines)
  • head injury or any condition that causes an increased pressure in the brain
  • acute porphyria (an inherited disorder that causes skin or nervous system abnormalities)
  • alcohol dependence
as Pentazocine may not be suitable for you.

Do not take Pentazocine if you ever had an allergic reaction (e.g. rashes, breathlessness, swollen eyes) to this medicine or similar painkillers.

Do not take Pentazocine if you are currently taking or have taken a medicine that is used to treat depression known as a monoamine oxidase inhibitor (MAOI) such as isocarboxazid, phenelzine and tranylcypromine in the last 14 days.
What should I take note of while taking this medicine?
Inform your doctor if you have the following conditions:
  • heart disease
  • liver disease
  • kidney disease
  • stomach disorders
  • thyroid disease
  • Addison’s disease (a rare disorder where the adrenal glands produce insufficient hormones)
  • tumour of the adrenal gland
  • inflammation of the pancreas
  • prostate enlargement
  • difficulty urinating
  • mood disorder
  • substance abuse
  • epilepsy (fits or seizures)
  • drug dependence
  • sleep disorders
Let your doctor know if you are pregnant or breastfeeding.

Be sure to check with your doctor or pharmacist before giving this medicine to the elderly, debilitated (a person who is physically or mentally weak usually due to illness or old age), or obese patient. They may be more sensitive to the side effects.

Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
  • Routine tests (e.g. lung function, bowel function) may be done while you are being treated with this medicine. Your doctor will advise you about how often you need to have these tests.
  • Your blood pressure may rise or fall to unsafe levels without you noticing it. Monitor your blood pressure during treatment.
  • There is a risk that you may become dependent, addicted or reliant to this medicine. Discuss with your doctor if you are concerned about these effects.
What side effects could I experience?
This medicine may cause drowsiness or dizziness. If affected, do not drive or take part in any activity in which you need to be alert.

Other side effects include any of the following: nausea, vomiting, diarrhoea, dizziness, headache, weakness, tremors, high or low blood pressure.

Some side effects may need immediate medical help. Alert your doctor quickly if you experience slow or ineffective breathing.

Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Can I take this with other medicines?
Do not take Pentazocine if you are currently taking or have taken medicine to treat depression known as a monoamine oxidase inhibitor (MAOI) such as isocarboxazid, phenelzine and tranylcypromine in the last 14 days.

Do not take this medicine with benzodiazepines (medicine for anxiety).

Inform your doctor and pharmacist if you are taking any of these medicines:
  • medicine for mood disorders e.g. chlorpromazine, thioridazine
  • other strong painkillers e.g. morphine
This list does not include all medicines that may interact with Pentazocine.

Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
What special dietary instructions should I follow?
Avoid alcohol. Alcohol intake may worsen the dizziness and drowsiness caused by Pentazocine.
How should I store this medicine?
Store in a cool, dry place away from the reach of children.

Protect from light.

Medicines must not be used past the expiry date.
This information is independently developed by MIMS based on pentazocine - oral and is provided for your reference only. It is not a replacement for and should only be used in conjunction with full consultation with a licensed healthcare professional, the information provided by your pharmacist and/or the manufacturer of the medication. It may not contain all the available information you require and cannot substitute professional medical care, nor does it take into account all individual circumstances. Although great effort has been made to ensure content accuracy, we shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2021 MIMS. All rights reserved. Powered by
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