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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


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.[Ref]

Cardiovascular side effects with the use of naloxone have included hypotension, hypertension, atrial and ventricular tachycardia, ventricular fibrillation, left ventricular failure and cardiac arrest (mostly in postoperative patients, many of whom had cardiovascular disease).

Cardiovascular side effects including a decrease in blood pressure and tachycardia have been reported infrequently with the use of pentazocine.[Ref]


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.[Ref]

Other side effect including withdrawal in patients receiving opioids have been precipitated by naloxone. Withdrawal is characterized by nausea, vomiting, sweating, lacrimation, rhinorrhea, cramping, insomnia, chills/hot flashes, piloerection, tachycardia, anxiety, restlessness, irritability, tremulousness, hypertension, seizures, and cardiac arrest. Similar symptoms have been noted in patients with pruritus of cholestasis who were not receiving opiates.

Other side effects including tinnitus have been reported with the use of pentazocine.[Ref]


Three cases, treated with numerous drugs, developed clinical evidence of pulmonary edema shortly after intravenous administration of naloxone (0.3 to 1.6 mg).[Ref]

Respiratory side effects including pulmonary edema have been uncommon from the use of naloxone.

Respiratory side effects including respiratory depression have rarely been reported with the use of pentazocine.[Ref]

Nervous system

A 51-year-old male was given 0.8 mg of naloxone for obtundation. Within 30 seconds of administration a grand mal seizure occurred. The patient had Pseudomonas sepsis with negative CSF cultures.[Ref]

Nervous system side effects including seizures and paresthesias have been reported at both standard and high dosages of naloxone. Seizures have been reported in 5% of patients receiving a bolus of 4 mg/kg followed by 2 mg/kg/h for 24 hours. Agitation has been noted in 3%, tremors in 3%, and headache in 5%. Rarely, agitation, tremors, headache, alteration in mood and cognition, mental discomfort, sleepiness, and confusion have been reported at high dosages. Lethargy has been reported in manic and control patients. Naloxone administration may worsen obsessive compulsive behavior.

Nervous system side effects including sweating, dizziness, lightheadedness, hallucinations, sedation, euphoria, headache, confusion, and disorientation have been reported with the use of pentazocine. Weakness, flushing, disturbed dreams, insomnia, and syncope have been reported infrequently. Tremor, chills, paresthesia, irritability, and excitement have been reported rarely.[Ref]


Gastrointestinal side effects of nausea and vomiting have been reported in patients receiving high dose naloxone therapy.

Gastrointestinal side effects including nausea and vomiting have been reported with the use of pentazocine. Constipation has been reported infrequently. Abdominal distress, anorexia, and diarrhea have been reported rarely.[Ref]

Nausea and/or vomiting occurred in 32% of patients in one study on naloxone who received a bolus of 4 mg/kg followed by 2 mg/kg/h for 24 hours.[Ref]


Genitourinary side effects including an increase in urinary urgency have rarely been reported with the use of naloxone. The drug may also have a mild diuretic effect.

Genitourinary side effects including urinary retention have rarely been reported with the use of pentazocine.[Ref]

A 75-year-old was treated with naloxone for senile dementia. A dosage of 0.8 mg in 25 mL of normal saline was given as an infusion over 10 minutes. The treatment was given 6 times, each time the patient experienced urinary urgency (at least 5 small volume urinations over 2 hours).[Ref]


Depression of the white blood cell count is usually reversible.[Ref]

Hematologic side effects including depression of the white blood cell count (especially granulocytes) and moderate transient eosinophilia have been reported with the use of pentazocine.[Ref]


Hypersensitivity reactions including rash have been reported infrequently. Urticaria and edema of the face have been reported rarely with the use of pentazocine. One instance of an apparent anaphylactic reaction has been reported.[Ref]


Dermatologic side effects including erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis have been reported rarely with the use of pentazocine.[Ref]


Ocular side effects including visual blurring and focusing difficulty have been reported infrequently with the use of pentazocine.[Ref]


Psychiatric side effects including depression have been reported infrequently with the use of pentazocine.[Ref]


1. Levin ER, Sharp B, Drayer JI, Weber MA "Severe hypertension induced by naloxone." Am J Med Sci 290 (1985): 70-2

2. Groeger JS, Inturrisi CE "High-dose naloxone: pharmacokinetics in patients in septic shock." Crit Care Med 15 (1987): 751-6

3. Chamberlain JM, Klein BL "A comprehensive review of naloxane for the emergency physician." Am J Emerg Med 12 (1994): 650-60

4. "Product Information. Narcan (naloxone)." DuPont Pharmaceuticals, Wilmington, DE.

5. Marone G "Tacrolimus ointment for atopic dermatitis." N Engl J Med 339 (1998): 1788

6. "Hoechst-Roussel Altace gains new indication for decreased risk of death." F-D-C Reports -- "The Pink Sheet" 57 (1995): t&g5-6

7. Harrington LW "Acute pulmonary edema following use of naloxone: a case study." Crit Care Nurse 8 (1988): 69-73

8. Brimacombe J, Archdeacon J, Newell S, Martin J "Two cases of naloxone-induced pulmonary oedema--the possible use of phentolamine in management." Anaesth Intensive Care 19 (1991): 578-80

9. Mariani PJ "Seizure associated with low-dose naloxone." Am J Emerg Med 7 (1989): 127-9

10. Leehey DJ, Gollapudi P, Deakin A, Reid RW "Naloxone increases water and electrolyte excretion after water loading in patients with cirrhosis and ascites." J Lab Clin med 118 (1991): 484-91

11. Sandyk R, Gillman MA "Naloxone causes urinary urgency." Urology 27 (1986): 79

Some side effects of Talwin Nx may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.