Pentazocine may be habit forming, especially with prolonged use. Take pentazocine exactly as directed. Do not take more of it, take it more often, or take it in a different way than directed by your doctor. While you are taking pentazocine, discuss with your health care provider your pain treatment goals, length of treatment, and other ways to manage your pain. Tell your doctor if you or anyone in your family drinks or has ever drunk large amounts of alcohol, uses or has ever used street drugs, or has overused prescription medications, or has had an overdose, or if you have or have ever had depression or another mental illness. There is a greater risk that you will overuse pentazocine if you have or have ever had any of these conditions. Talk to your health care provider immediately and ask for guidance if you think that you have an opioid addiction or call the U.S. Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-HELP.
Pentazocine may cause serious or life-threatening breathing problems, especially during the first 24 to 72 hours of your treatment and any time your dose is increased. Your doctor will monitor you carefully during your treatment. Tell your doctor if you have or have ever had slowed breathing or asthma. Your doctor will probably tell you not to take pentazocine. Also tell your doctor if you have or have ever had lung disease such as chronic obstructive pulmonary disease (COPD; a group of diseases that affect the lungs and airways), a head injury, a brain tumor, or any condition that increases the amount of pressure in your brain. The risk that you will develop breathing problems may be higher if you are an older adult or are weak or malnourished due to disease. If you experience any of the following symptoms, call your doctor immediately or get emergency medical treatment: slowed breathing, long pauses between breaths, or shortness of breath.
Do not allow anyone else to take your medication. Pentazocine may harm or cause death to other people who take your medication, especially children. Keep pentazocine in a safe place so that no one else can take it accidentally or on purpose. Be especially careful to keep pentazocine out of the reach of children. Keep track of how many capsules or tablets are left so you will know if any medication is missing.
Taking certain medications other medications with pentazocine may increase the risk that you will develop serious or life-threatening breathing problems, sedation, or coma. Tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medication and will monitor you carefully. If you take pentazocine with other medications and you develop any of the following symptoms, call your doctor immediately or seek emergency medical care: unusual dizziness, lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness. Be sure that your caregiver or family members know which symptoms may be serious so they can call the doctor or emergency medical care if you are unable to seek treatment on your own.
Drinking alcohol, taking prescription or nonprescription medications that contain alcohol, or using street drugs during your treatment with pentazocine increases the risk that you will experience these serious, life-threatening side effects. Do not drink alcohol, take prescription or nonprescription medications that contain alcohol, or use street drugs during your treatment.
Tell your doctor if you are pregnant or plan to become pregnant. If you take pentazocine regularly during your pregnancy, your baby may experience life-threatening withdrawal symptoms after birth. Tell your baby's doctor right away if your baby experiences any of the following symptoms: irritability, hyperactivity, abnormal sleep, high-pitched cry, uncontrollable shaking of a part of the body, vomiting, diarrhea, or failure to gain weight.
Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin your treatment with pentazocine and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website ( https://www.fda.gov/Drugs/DrugSafety/ucm085729.htm ) or the manufacturer's website to obtain the Medication Guide.
Talk to your doctor about the risks of taking pentazocine.
Why is this medicine prescribed?
Pentazocine is used to relieve severe pain in people who are expected to need an opioid pain medication and who cannot be treated with other pain medications. Pentazocine is in a class of medications called opiate (narcotic) analgesics. It works by changing the way the brain and nervous system respond to pain.
Are there other uses for this medicine?
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
How should this medicine be used?
Pentazocine comes as a tablet to take by mouth. It usually is taken every 3 to 4 hours as needed. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take pentazocine exactly as directed.
Pentazocine tablets should be taken by mouth. Do not try to dissolve and inject the tablets. Injecting pentazocine may cause serious health problems or death. Naloxone is added to the tablets so that people who inject dissolved tablets will not experience the desired effects of pentazocine.
Your doctor may adjust your dose of pentazocine during your treatment, depending on how well your pain is controlled and on the side effects that you experience. Talk to your doctor about how you are feeling during your treatment with pentazocine. Tell your doctor if you feel that your pain is not controlled or if your pain increases, becomes worse, or if you have new pain or an increased sensitivity to pain during your treatment with pentazocine. Do not take more of it or take it more often than prescribed by your doctor.
Do not stop taking pentazocine without talking to your doctor. If you suddenly stop taking hydrocodone, you may experience withdrawal symptoms such as restlessness, teary eyes, runny nose, yawning, sweating, chills, hair standing on end, muscle pain, widened pupils (black circles in the middle of the eyes), irritability, anxiety, back or joint pain, weakness, stomach cramps, difficulty falling asleep or staying asleep, nausea, loss of appetite, vomiting, diarrhea, fast breathing, or fast heartbeat. Your doctor will probably decrease your dose gradually.
What special precautions should I follow?
Before taking pentazocine,
- tell your doctor and pharmacist if you are allergic to pentazocine, naloxone, any other medications, or any of the ingredients in pentazocine tablets. Ask your doctor or pharmacist for a list of the ingredients.
- tell your doctor or pharmacist if you are taking the following medications or have stopped taking them within the past two weeks: isocarboxazid (Marplan), linezolid (Zyvox), methylene blue, phenelzine (Nardil), selegiline (Emsam, Zelapar), or tranylcypromine (Parnate).
- tell your doctor if you have any of the conditions mentioned in the IMPORTANT WARNING section, a blockage or narrowing of your stomach or intestines, or paralytic ileus (condition in which digested food does not move through the intestines). Your doctor may tell you not to take pentazocine.
- tell your doctor if you have or have ever had problems urinating; low blood pressure; adrenal insufficiency (condition in which the adrenal glands do not produce enough of certain hormones needed for important body functions); diabetes; seizures; liver, kidney, thyroid, gallbladder, pancreas, or heart disease.
- tell your doctor if you are breastfeeding. Pentazocine can cause shallow breathing, difficulty or noisy breathing, confusion, more than usual sleepiness, trouble breastfeeding, or limpness in breastfed infants.
- you should know that this medication may decrease fertility in men and women. Talk to your doctor about the risks of taking pentazocine.
- you should know that this medication may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
- talk to your doctor about the safe use of this medication if you are 65 years of age or older. Older adults should not usually take pentazocine because it is not as safe as other medications that can be used to treat the same condition.
- you should know that pentazocine may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking pentazocine. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.
- you should know that pentazocine may cause constipation. Talk to your doctor about changing your diet and using other medications to treat or prevent constipation.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking pentazocine.
What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do if I forget to take a dose?
This medication usually is taken as needed. If your doctor has told you to take pentazocine regularly, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.
What should I do in case of overdose?
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help . If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
While taking pentazocine, you should talk to your doctor about having a rescue medication called naloxone readily available (e.g., home, office). Naloxone is used to reverse the life-threatening effects of an overdose. It works by blocking the effects of opiates to relieve dangerous symptoms caused by high levels of opiates in the blood. Your doctor may also prescribe you naloxone if you are living in a household where there are small children or someone who has abused street or prescription drugs. Ask your doctor about other ways that you can obtain naloxone (directly from a pharmacy or as part of a community based program). You should make sure that you and your family members, caregivers, or the people who spend time with you know how to recognize an overdose, how to use naloxone, and what to do until emergency medical help arrives. Your doctor or pharmacist will show you and your family members how to use the medication. Ask your pharmacist for the instructions or visit the manufacturer's website to get the instructions. If symptoms of an overdose occur, a friend or family member should give the first dose of naloxone, call 911 immediately, and stay with you and watch you closely until emergency medical help arrives. Your symptoms may return within a few minutes after you receive naloxone. If your symptoms return, the person should give you another dose of naloxone. Additional doses may be given every 2 to 3 minutes, if symptoms return before medical help arrives.
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help . If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
Symptoms of overdose may include the following:
- slow or shallow breathing
- difficulty breathing
- extreme sleepiness
- unable to respond or wake up
- muscle weakness
- cold, clammy skin
- narrowed or widened pupils (dark circles in the middle of the eyes)
- slowed heartbeat
- unusual snoring
What side effects can this medicine cause?
Pentazocine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- feeling very tired
- lightheadedness
- drowsiness
- headache
- constipation
- stomach pain
- difficulty urinating
Some side effects can be serious. If you experience any of the following symptoms or those listed in the IMPORTANT WARNING section, call your doctor immediately:
- changes in heartbeat
- agitation, hallucinations (seeing things or hearing voices that do not exist), fever, sweating, confusion, fast heartbeat, shivering, severe muscle stiffness or twitching, loss of coordination, nausea, vomiting, or diarrhea
- nausea, vomiting, loss of appetite, weakness, or dizziness
- inability to get or keep an erection
- irregular menstruation
- decreased sexual desire
- rash; hives; hoarseness; difficulty breathing or swallowing; or swelling of the face, mouth, tongue or throat
- fainting
Pentazocine may cause other side effects. Call your doctor if you have any unusual problems while you are taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( http://www.fda.gov/Safety/MedWatch ) or by phone (1-800-332-1088).
What should I know about storage and disposal of this medication?
Keep this medication in the container it came in, tightly closed, and out of reach of children, and in a location that is not easily accessible by others, including visitors to the home. Store it at room temperature and away from excess heat and moisture (not in the bathroom). You must immediately dispose of any medication that is outdated or no longer needed through a medicine take-back program.. If you do not have a take-back program nearby or one that you can access promptly, flush any pentazocine tablets that are outdated or no longer needed down the toilet. Talk to your pharmacist about the proper disposal of your medication.
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org
What other information should I know?
Keep all appointments with your doctor and laboratory. Your doctor may order certain lab tests to check your body's response to pentazocine.
Before having any laboratory test (especially those that involve methylene blue), tell your doctor and the laboratory personnel that you are taking pentazocine.
Do not let anyone else take your medication. Pentazocine is a controlled substance. Prescriptions may be refilled only a limited number of times; ask your pharmacist if you have any questions.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.