Health Library

Pentazocine (By injection)

Pentazocine (pen-TAZ-oh-seen)

Treats moderate to severe pain given before or after a surgery. May also be given with a general anesthesia before an operation. This medicine is a narcotic.

Brand Name(s):

When This Medicine Should Not Be Used:

How to Use This Medicine:

Injectable

• Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given as a shot under your skin, into a muscle, or into a vein.
• A nurse or other health provider will give you this medicine.
• You may be taught how to give your medicine at home. Make sure you understand all instructions before giving yourself an injection. Do not use more medicine or use it more often than your doctor tells you to.
• You will be shown the body areas where this shot can be given. Use a different body area each time you give yourself a shot. Keep track of where you give each shot to make sure you rotate body areas.
• Use a new needle and syringe each time you inject your medicine.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• If you store this medicine at home, keep it at room temperature, away from heat and direct light.
• Throw away used needles in a hard, closed container that the needles cannot poke through. Keep this container away from children and pets.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Some medicines can affect how pentazocine works. Tell your doctor if you are using any of the following:
  • Mirtazapine, tramadol, trazodone
  • Benzodiazepine medicine
  • Diuretic medicine
  • Medicine to treat anxiety, depression, or mental health problems
  • Phenothiazine medicine
  • Triptan medicine to treat migraine headache
• Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol. Tell your doctor if you are using buprenorphine, butorphanol, nalbuphine, pentazocine, or a muscle relaxer.
• Do not drink alcohol while you are using this medicine.

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, breathing or lung problems, heart attack, heart failure, high blood pressure, adrenal problems, gallbladder problems, pancreas problems, stomach problems, or a history of head injury, seizures, or alcohol or drug abuse. Tell your doctor if you had an allergy to sulfites.
• This medicine may cause the following problems:
  • High risk of overdose, which can lead to death
  • Respiratory depression (serious breathing problem that can be life-threatening)
  • Serotonin syndrome (when used with certain medicines)
• This medicine can be habit-forming. Do not use more than your prescribed dose. Call your doctor if you think your medicine is not working.
• Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
• This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you.
• This medicine may cause constipation, especially with long-term use. Ask your doctor if you should use a laxative to prevent and treat constipation.
• This medicine could cause infertility. Talk with your doctor before using this medicine if you plan to have children.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Anxiety, restlessness, fast heartbeat, fever, sweating, muscle spasms, twitching, nausea, vomiting, diarrhea, seeing or hearing things that are not there
• Blue lips, fingernails, or skin
• Extreme dizziness or weakness, shallow breathing, slow or uneven heartbeat, sweating, cold or clammy skin, seizures
• Fast, slow, or pounding heartbeat
• Redness, pain, swelling, blistering, or hardening of your skin where the shot was given
• Severe confusion, lightheadedness, dizziness, fainting
• Severe constipation or stomach pain
• Troubled breathing

If you notice these less serious side effects, talk with your doctor:

• Drowsiness or sleepiness
• Headache, dry mouth, blurred vision
• Mild constipation, diarrhea, nausea, vomiting, or upset stomach
• Sweating more than usual
• Warmth or redness in your face, neck, arms, or upper chest

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 9/6/2024