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, 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.
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 if you are taking or plan to take any of the following medications: certain antifungal medications including itraconazole (Onmel, Sporanox), ketoconazole (Nizoral), and voriconazole (Vfend); benzodiazepines such as alprazolam (Xanax), chlordiazepoxide (Librium), clonazepam (Klonopin), diazepam (Diastat, Valium), estazolam, flurazepam, lorazepam (Ativan), oxazepam, temazepam (Restoril), and triazolam (Halcion); carbamazepine (Carbatrol, Epitol, Tegretol, Teril); clarithromycin (Biaxin, in PrevPac); erythromycin (Erytab, Erythrocin);certain medications for human immunodeficiency virus (HIV) including indinavir (Crixivan), nelfinavir (Viracept), and ritonavir (Norvir, in Kaletra); medications for mental illness, nausea, or pain; muscle relaxants; phenytoin (Dilantin, Phenytek); rifampin (Rifadin, Rimactane, in Rifamate); sedatives; sleeping pills; or tranquilizers. Your doctor may need to change the doses of your medication and will monitor you carefully. If you take pentazocine with any of these 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.
Pentazocine may be habit-forming. Do not take more of it, take it more often, or take it in a different way than directed by your doctor. 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 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.
Do not allow anyone else to take your medication. Pentazocine may harm or cause death to other people who take your medication, especially children.
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.
Talk to your doctor about the risks of taking pentazocine.
Why is this medication prescribed?
Pentazocine is used to relieve moderate to severe pain. 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.
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.
Other uses for this medicine
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
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 and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: medications for migraine headaches such as almotriptan (Axert), eletriptan (Relpax), frovatriptan (Frova), naratriptan (Amerge), rizatriptan (Maxalt), sumatriptan (Alsuma, Imitrex, in Treximet), and zolmitriptan (Zomig); medications for cough, cold, or allergies; 5HT3 serotonin blockers such as alosetron (Lotronex), dolasetron (Anzemet), granisetron (Kytril), ondansetron (Zofran, Zuplenz), or palonosetron (Aloxi); selective serotonin-reuptake inhibitors such as citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac, Sarafem, in Symbyax), fluvoxamine (Luvox), paroxetine (Brisdelle, Prozac, Pexeva), and sertraline (Zoloft); serotonin and norepinephrine reuptake inhibitors such as desvenlafaxine (Khedezla, Pristiq), duloxetine (Cymbalta), milnacipran (Savella), and venlafaxine (Effexor); tramadol; trazodone (Oleptro); and tricyclic antidepressants ('mood elevators') such as amitriptyline, clomipramine (Anafranil), desipramine (Norpramin), doxepin (Silenor), imipramine (Tofranil), nortriptyline (Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil). Also tell your doctor or pharmacist if you are taking or receiving any of the following medications or have stopped taking them within the past 2 weeks: monoamine oxidase (MAO) inhibitors such as isocarboxazid (Marplan), linezolid (Zyvox), methylene blue, phenelzine (Nardil), rasagiline (Azilect), selegiline (Emsam, Eldepryl, Zelapar), and tranylcypromine (Parnate). Many other medications may also interact with pentazocine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor what herbal products you are taking, especially St. John's wort.
- tell your doctor if you have or have ever had problems urinating; seizure disorders; lung, liver, kidney, thyroid, gallbladder, or heart disease.
- tell your doctor if you are breastfeeding.
- you should know that this medication may decrease fertility in men and women. Talk to your doctor about the risks of taking pentazocine.
- 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.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are 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.
What special dietary instructions should I follow?
Unless your doctor tells you otherwise, continue your normal diet.
What should I do if I forget 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 side effects can this medication cause?
Pentazocine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- feeling very tired
- mood changes
- upset stomach
- stomach pain
- difficulty urinating
Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:
- difficulty breathing
- 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
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. Store it at room temperature and away from excess heat and moisture (not in the bathroom).
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.
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
In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
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.
¶ This branded product is no longer on the market. Generic alternatives may be available.