Generic name: pentazocine (pen-TAZ-oh-seen)
Drug class: Narcotic analgesics
Medically reviewed by Drugs.com. Last updated on Oct 29, 2021.
Use of pentazocine lactate increases the risk of opioid addiction, abuse, or misuse, which may cause overdose or death. Assess the risk prior to therapy and monitor for signs of addiction, abuse, or misuse during therapy. Serious, life-threatening, or fatal respiratory depression may occur, particularly at treatment initiation and with dose increases. Monitor for signs of respiratory depression during treatment. Prolonged use during pregnancy may result in neonatal opioid withdrawal syndrome, which may be life-threatening if unnoticed and untreated. If prolonged use is required in a pregnant woman, advise the patient of the risk to the fetus. Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing for patients with inadequate alternative treatment options. Limit dosages and durations to the minimum required, and follow patients for signs and symptoms of respiratory depression and sedation .
Commonly used brand name(s)
In the U.S.
Pharmacologic Class: Opioid Agonist/Antagonist
Uses for pentazocine
Pentazocine injection is used to relieve moderate to severe pain. It may also be used before surgery or with a general anesthetic (medicine that puts you to sleep). Pentazocine belongs to the group of medicines called narcotic analgesics (pain medicines). It acts on the central nervous system (CNS) to relieve pain.
When a narcotic medicine is used for a long time, it may become habit-forming, causing mental or physical dependence. However, people who have continuing pain should not let the fear of dependence keep them from using narcotics to relieve their pain. Mental dependence (addiction) is not likely to occur when narcotics are used for this purpose. Physical dependence may lead to withdrawal side effects if treatment is stopped suddenly. However, severe withdrawal side effects can usually be prevented by gradually reducing the dose over a period of time before treatment is stopped completely.
Pentazocine is available only with your doctor's prescription.
Before using pentazocine
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For pentazocine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to pentazocine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of pentazocine injection in children 1 to 16 years of age. Safety and efficacy have not been established in children younger than 1 year of age.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of pentazocine injection in the elderly. However, elderly patients may be more sensitive to the effects of pentazocine injection than younger adults, and are more likely to have age-related kidney problems, which may require caution and an adjustment in the dose for patients receiving pentazocine injection.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving pentazocine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using pentazocine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using pentazocine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Calcium Oxybate
- Chloral Hydrate
- Eslicarbazepine Acetate
- Gabapentin Enacarbil
- Magnesium Oxybate
- Methylene Blue
- Nitrous Oxide
- Opium Alkaloids
- Potassium Oxybate
- Ropeginterferon Alfa-2b-njft
- Sodium Oxybate
- St John's Wort
- Tolonium Chloride
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using pentazocine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use pentazocine, or give you special instructions about the use of food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of pentazocine. Make sure you tell your doctor if you have any other medical problems, especially:
- Adrenal problems or
- Alcohol abuse, or history of or
- Allergy to sulfites or
- Breathing problems, severe (eg, COPD, hypercapnia, hypoxia) or
- Cor pulmonale or
- Depression, history of or
- Drug dependence, especially with narcotics, or history of or
- Head injuries, history of or
- Mental health problems or
- Weakened physical condition—Use with caution. May increase risk for more serious side effects.
- Asthma, severe or
- Respiratory depression (very slow breathing) or
- Stomach or bowel blockage (eg, paralytic ileus)—Should not be used in patients with these conditions.
- Heart attack, recent or
- Heart failure or
- Hypertension (high blood pressure) or
- Seizures, history of—Use with caution. May make these conditions worse.
- Kidney disease or
- Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
Proper use of pentazocine
A nurse or other trained health professional will give you or your child pentazocine in a hospital. Pentazocine may be given as a shot under your skin, into a muscles or a vein.
Your doctor will give you a few doses of pentazocine until your condition improves, and then switch you or your child to an oral medicine that works the same way. If you have any concerns about this, talk to your doctor.
Precautions while using pentazocine
It is very important that your doctor check the progress of you or your child while you are receiving pentazocine. This will allow your doctor to see if the medicine is working properly and to decide if you or your child should continue to use it.
Pentazocine may be habit-forming. If you or your child feel that the medicine is not working as well, do not use more than your prescribed dose. Call your doctor for instructions.
Using narcotics for a long time can cause severe constipation. To prevent this, your doctor may direct you or your child to take laxatives, drink a lot of fluids, or increase the amount of fiber in your diet. Be sure to follow the directions carefully, because continuing constipation can lead to more serious problems.
Pentazocine may cause skin or tissue damage at the injection site. Tell your doctor right away if you notice any of these symptoms at the injection site: depressed or indented skin, blue-green to black skin discoloration, or pain, redness, or peeling of the skin.
Pentazocine will add to the effects of alcohol and other CNS depressants (medicines that can make you drowsy or less alert). Some examples of CNS depressants are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicine, other prescription pain medicine or narcotics, medicine for seizures or barbiturates, muscle relaxants, or anesthetics, including some dental anesthetics. Check with your doctor before you or your child take any of the medicines listed above while you are using pentazocine.
Pentazocine may make you dizzy, drowsy, confused, or disoriented. Make sure you know how you react to pentazocine before you drive, use machines, or do anything else that could be dangerous if you are dizzy or not alert.
Pentazocine may cause allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you or your child have a rash, itching, hoarseness, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using pentazocine.
If you or your child have been using pentazocine regularly for several weeks or longer, do not suddenly stop using it without checking with your doctor. Your doctor may want you to gradually reduce the amount you are using before stopping it completely. This may help prevent worsening of your condition and reduce the possibility of withdrawal symptoms, such as abdominal or stomach cramps, anxiety, fever, nausea, runny nose, sweating, tremors, or trouble sleeping.
Using too much of pentazocine may cause infertility (unable to have children). Talk with your doctor before using pentazocine if you plan to have children.
Using pentazocine while you are pregnant may cause neonatal withdrawal syndrome in your newborn babies. Tell your doctor right away if your baby has an abnormal sleep pattern, diarrhea, a high-pitched cry, irritability, shakiness or tremors, weight loss, vomiting, or fails to gain weight.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Pentazocine side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor or nurse immediately if any of the following side effects occur:
- Black, tarry stools
- blistering, peeling, or loosening of the skin
- chest pain
- fast, pounding, or irregular heartbeat or pulse
- joint or muscle pain
- painful or difficult urination
- red, irritated eyes
- red skin lesions, often with a purple center
- shakiness in the legs, arms, hands, or feet
- sore throat
- sores, ulcers, or white spots on the lips or in the mouth
- swelling or puffiness of the face
- swollen glands
- trembling or shaking of the hands or feet
- trouble breathing
- unusual bleeding or bruising
- unusual tiredness or weakness
Incidence not known
- Blistering, crusting, irritation, itching, or reddening of the skin
- blue-green to black skin discoloration
- bluish lips or skin
- blurred vision
- burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
- cold, clammy skin
- cracked, dry, or scaly skin
- decrease in the frequency of urination
- decrease in urine volume
- difficult or troubled breathing
- difficulty in passing urine (dribbling)
- fast or slow heartbeat
- fast, weak pulse
- flushed skin
- hardening or thickening of the skin
- increased sweating
- irregular, fast, slow, or shallow breathing
- pain, redness, or sloughing of the skin at the injection site
- pale or blue lips, fingernails, or skin
- pounding in the ears
- rapid breathing
- small lumps under the skin at the injection site
- stinging at the injection site
- swelling of the lower legs or arms
- tightness in the chest
- very slow breathing
- weight gain
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- False or unusual sense of well-being
- Change in taste
- confusion about identity, place, and time
- constricted, pinpoint, or small pupils (black part of the eye)
- double vision
- seeing double seeing, hearing, or feeling things that are not there
- stomach cramps
- trouble sleeping
- uncontrolled eye movements
Incidence not known
- Continuing ringing or buzzing or other unexplained noise in the ears
- difficulty having a bowel movement (stool)
- difficulty in focusing the eyes
- disturbed dreams
- dry mouth
- hearing loss
- relaxed and calm
- trouble sleeping
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
More about pentazocine
- Side Effects
- During Pregnancy or Breastfeeding
- Dosage Information
- Drug Interactions
- 12 Reviews
- Drug class: narcotic analgesics
- Other brands
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Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.