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Talwin Nx Side Effects

Generic Name: naloxone / pentazocine

Note: This document contains side effect information about naloxone / pentazocine. Some of the dosage forms listed on this page may not apply to the brand name Talwin Nx.

For the Consumer

Applies to naloxone / pentazocine: oral tablet

Along with its needed effects, naloxone/pentazocine 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 immediately if any of the following side effects occur while taking naloxone / pentazocine:


  • Black, tarry stools
  • chest pain
  • chills
  • cough or hoarseness
  • difficult or troubled breathing
  • fever
  • fever with or without chills
  • general feeling of tiredness or weakness
  • irregular, fast or slow, or shallow breathing
  • lower back or side pain
  • painful or difficult urination
  • pale or blue lips, fingernails, or skin
  • shakiness in the legs, arms, hands, or feet
  • shortness of breath
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • swollen glands
  • trembling or shaking of the hands or feet
  • unusual bleeding or bruising
  • unusual tiredness or weakness

Incidence Not Known

  • Blistering, peeling, or loosening of the skin
  • blurred vision
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • confusion
  • decrease in the frequency of urination
  • diarrhea
  • difficulty in passing urine (dribbling)
  • difficulty with swallowing
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fainting
  • fast, slow, pounding, or irregular heartbeat or pulse
  • feeling of warmth
  • headache
  • hives
  • itching
  • joint or muscle pain
  • loss of bladder control
  • loss of consciousness
  • nervousness
  • pounding in the ears
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • rapid breathing
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • redness of the face, neck, arms, and occasionally, upper chest
  • skin rash
  • sweating
  • swelling of the lower legs or arms
  • swelling of the face
  • tightness in the chest
  • total body jerking
  • upper abdominal or stomach pain
  • weight gain
  • wheezing

Get emergency help immediately if any of the following symptoms of overdose occur while taking naloxone / pentazocine:

Symptoms of Overdose

  • Seeing, hearing, or feeling things that are not there
  • seizures (convulsions)
  • sleepiness or unusual drowsiness

Some side effects of naloxone / pentazocine 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:


  • Abdominal or stomach distress
  • hives or welts
  • redness of the skin

Incidence Not Known

  • Blistering, crusting, irritation, itching, or reddening of the skin
  • confusion about identity, place, and time
  • constipation
  • constricted, pinpoint, or small pupils (black part of the eye)
  • continuing ringing or buzzing or other unexplained noise in the ears
  • cracked, dry, or scaly skin
  • depression
  • difficulty in focusing the eyes
  • disturbed dreams
  • drowsiness
  • dry mouth
  • excitement
  • false or unusual sense of well-being
  • hearing loss
  • irritability
  • lightheadedness
  • loss of appetite
  • mood or mental changes
  • nausea
  • relaxed and calm feeling
  • trouble with sleeping
  • unable to sleep
  • vomiting
  • weakness
  • weight loss

For Healthcare Professionals

Applies to naloxone / pentazocine: oral tablet


The most commonly occurring adverse reactions have included nausea, dizziness, lightheadedness, vomiting, and euphoria.[Ref]


Postmarketing reports: Respiratory depression


Postmarketing reports: Hallucinations (usually visual), confusion, disorientation, depression, euphoria, disturbed dreams, insomnia, irritability, excitement, irritability


Postmarketing reports: Anaphylaxis, facial edema, rash


Postmarketing reports: Hypertension, hypotension, circulatory depression, tachycardia, syncope

A 45-year-old male narcotic addict and alcoholic with hepatitis and undiscovered cardiomyopathy was given 0.8 mg of naloxone intravenously over a 2 minute period and developed ventricular fibrillation. The patient required naloxone once more for this episode and again developed ventricular fibrillation. A second opioid overdose in the same patient was treated with an initial dose of 0.4 mg intravenously, followed by 0.4 mg intravenously, then intramuscularly. Each time the patient developed ventricular fibrillation responsive to cardioversion and/or lidocaine.

Severe hypertension (mean arterial pressure rising from a baseline of 107 mmHg to 147 mmHg in about 2 to 3 hours) has been reported in an essential hypertension patient given an initial 8 mg dose of naloxone intravenously, followed by an infusion of 0.13 mg/min over the next 2.5 hours. When the naloxone was discontinued the blood pressure quickly returned to normal.

Mild hypotension and one case of moderate hypertension were observed in patients receiving a bolus dose of 4 mg/kg of naloxone followed by 2 mg/kg/hour for 24 hours. One study reported that the newborn infants of mothers who have received naloxone near term may experience tachycardia.


Postmarketing reports: Nausea, vomiting, constipation, diarrhea, anorexia, biliary tract spasms, dry mouth, abdominal distress


Postmarketing reports: Sweating, flushed skin, dermatitis, pruritus, rash, urticaria, serous skin reactions including erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis


Postmarketing reports: Tinnitus, chills

Withdrawal syndromes from the use of naloxone may be precipitated by as little as 0.05 to 0.2 mg intravenously in patients taking 24 mg per day of methadone.


Postmarketing reports: Visual blurring and focusing difficulty, blurred vision, diplopia, miosis, nystagmus


Postmarketing reports: Urinary retention, alteration in rate or strength of labor contractions


Postmarketing reports: Depression of the white blood cell count (especially granulocytes), moderate transient eosinophilia, agranulocytosis

Depression of the white blood cell count is usually reversible.



Postmarketing reports: Adrenal insufficiency, androgen deficiency

Cases of adrenal insufficiency have been reported with opioid use, generally use greater than 1 month. Cases of androgen deficiency have been reported with chronic opioid use.


1. "Product Information. Naloxone HCl-Pentazocine HCl (naloxone-pentazocine)." Actavis U.S. (Amide Pharmaceutical Inc), Little Falls, NJ.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.