Health Library

Pentazocine/acetaminophen (By mouth)

Acetaminophen (a-seet-a-MIN-oh-fen), Pentazocine Hydrochloride (pen-TAZ-oh-seen hye-droe-KLOR-ide)

Relieves mild to moderate pain. This medicine contains a narcotic pain medicine.

Brand Name(s):

When This Medicine Should Not Be Used:

How to Use This Medicine:

Tablet

• Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
• You may take this medicine with or without food.
• This medicine contains acetaminophen. Read the labels of all other medicines you are using to see if they also contain acetaminophen, or ask your doctor or pharmacist. Do not use more than 4 grams (4,000 milligrams) total of acetaminophen in one day.

If a dose is missed:

• 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.

How to Store and Dispose of This Medicine:

• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Make sure you store the medicine in a safe and secure place to prevent others from getting it.
• Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Drugs and Foods to Avoid:

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

• Make sure your doctor knows if you have received an MAO inhibitor (MAOI) such as Eldepryl®, Marplan®, Nardil®, or Parnate® within the past 14 days. Tell your doctor if you are also using an anticholinergic medicine (such as glycopyrrolate, ipratropium, or Atrovent®) or a phenothiazine medicine (such as prochlorperazine, Compazine®, Mellaril®, Phenergan®, Thorazine®, or Trilafon®).
• Tell your doctor if you smoke tobacco. Smoking may change how well this medicine works.
• Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol.
• Do not drink alcohol while you are using this medicine. Large doses of acetaminophen can damage your liver. If you regularly drink 3 or more alcoholic drinks every day, do not take acetaminophen without asking your doctor.
• Do not also use other medicines that contain acetaminophen (Tylenol®), or you may be getting more than a safe amount of this medicine.
• Many combination medicines contain acetaminophen, including products with brand names such as Alka-Seltzer Plus®, Comtrex®, Drixoral®, Excedrin Migraine®, Midol®, Sinutab®, Sudafed®, Theraflu®, and Vanquish®. Carefully check the labels of all other medicines you are using to be sure they do not contain acetaminophen.

Warnings While Using This Medicine:

• Make sure your doctor knows if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, heart or blood vessel disease, high blood pressure, a recent heart attack, or a history of head injury, seizures, or recent surgery. Tell your doctor if you have adrenal problems, asthma or other lung problems (such as COPD, respiratory depression), gallbladder problems, kyphoscoliosis (severe curvature of the spine with breathing problems), mental illness, pancreas problems, porphyria (an enzyme problem), an enlarged prostate, bowel blockage, stomach problems, or an underactive thyroid. Tell your doctor if you have been addicted to alcohol or drugs.
• Check with your doctor right away if you or your child have pain or tenderness in the upper stomach; pale stools; dark urine; loss of appetite; nausea; unusual tiredness or weakness; or yellow eyes or skin. These could be symptoms of a serious liver problem.
• This medicine 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 this medicine.
• Make sure your doctor knows if you or your child have received narcotic medicines (such as methadone) in the past. Some patients receiving narcotic pain medicines, have experienced withdrawal symptoms after receiving pentazocine.
• Check with your doctor if you or your child have confusion about identity, place, and time; mood or mental changes; or seeing things that are not there while taking this medicine.
• 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.
• Tell any doctor or dentist who treats you that you are using this medicine. You may need to stop using this medicine several days before you have surgery or medical tests.
• This medicine may make you dizzy or drowsy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert.
• This medicine may cause constipation, especially with long-term use. Ask your doctor if you should use a laxative to prevent and treat constipation.
• Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.

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
• Blistering, peeling, or red skin rash.
• Dark-colored urine or pale stools.
• Decrease in how much or how often you urinate.
• Extreme weakness, shallow breathing, sweating, or cold or clammy skin.
• Fast, slow, or uneven heartbeat.
• Fever, chills, cough, sore throat, and body aches.
• Lightheadedness, dizziness, or fainting.
• Nausea, vomiting, loss of appetite, or pain in your upper stomach.
• Numbness, tingling, or burning pain in your hands, arms, legs, or feet.
• Seizures.
• Severe confusion or hallucinations (seeing things that are not there).
• Severe stomach pain.
• Sleepiness or unusual drowsiness.
• Yellowing of your skin or the whites of your eyes.

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

• Blurred vision.
• Constipation, diarrhea, nausea, vomiting, or upset stomach.
• Dry mouth.
• Feeling depressed or irritable.
• Headache or trouble sleeping.
• Mild skin rash or itching.
• Warmth or redness in your face, neck, arms, or upper chest.
• Weakness.

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: 9/4/2017