pentazocine lactate


pentazocine hydrochloride and acetaminophen

Fortral (UK)

pentazocine hydrochloride and naloxone hydrochloride

Pharmacologic class: Opioid agonist-antagonist

Therapeutic class: Opioid analgesic, adjunct to anesthesia

Controlled substance schedule IV Pregnancy risk category C

FDA Box Warning

• When administering pentazocine hydrochloride and acetaminophen, be aware that acetaminophen has been associated with acute liver failure, at times resulting in liver transplant or death. Most of the cases of liver injury are associated with the use of acetaminophen at dosages that exceed 4,000 mg/day, and often involve more than one acetaminophen-containing product.

• Pentazocine and naloxone hydrochloride tablets are for oral use only. Severe, potentially lethal reactions may result from misuse by injection, alone or in combination with other substances.


Unknown. Thought to interact with opioid receptor sites primarily in limbic system, thalamus, and spinal cord, blocking transmission of pain impulses.


Injection: 30 mg/ml (as lactate salt) Tablets: 50 mg pentazocine and 0.5 mg naloxone (Talwin NX); 25 mg pentazocine and 650 mg acetaminophen (Talacen)

Indications and dosages

Moderate to severe pain; preoperative or preanesthetic medication; adjunct to surgical anesthesia

Adults: 30 mg subcutaneously, I.M., or I.V. q 3 to 4 hours (not to exceed 60 mg/dose subcutaneously or I.M., or 30 mg/dose I.V.). Maximum daily dosage is 360 mg.

Moderate to severe pain

Adults: Initially, one tablet (Talwin Nx) q 3 to 4 hours, increased to two tablets p.r.n., up to a maximum of 12 tablets daily

Mild to moderate pain

Adults: One tablet (Talacen) P.O. q 4 hours; up to a maximum of six tablets daily


Adults: 20 mg I.V. for two or three doses at 2- to 3-hour intervals, or 30 mg I.M. as a single dose


• Hypersensitivity to drug, acetaminophen, or naloxone (with oral form)


Use cautiously in:

• head trauma, increased intracranial pressure, respiratory conditions, adrenal insufficiency, seizure disorder, acute CNS manifestations, hepatic impairment, acute myocardial infarction, alcohol or narcotic use

• sulfite sensitivity (Talacen)

• history of drug abuse

• pregnant or breastfeeding patients

• children (safety not established).


• Administer each 5-mg I.V. dose by slow direct infusion over 1 minute, with patient lying supine.

• Use subcutaneous route only when necessary (may cause tissue damage).

Adverse reactions

CNS: dizziness, drowsiness, euphoria, hallucinations, headache, sedation, dysphoria, insomnia, unusual dreams, weakness, depression, irritability, excitement, tremor, paresthesia

CV: hypertension, hypotension, syncope, tachycardia, circulatory depression, shock

EENT: blurred vision, diplopia, nystagmus, miosis (with high doses), tinnitus

GI: nausea, vomiting, constipation, diarrhea, dry mouth, ileus, cramps, abdominal distress, anorexia

GU: urinary retention, altered rate and strength of labor contractions Hematologic: thrombocytopenia purpura (with Talacen)

Respiratory: dyspnea, transient apnea in neonates whose mothers received pentazocine during labor, respiratory depression

Skin: clammy skin, diaphoresis, rash, urticaria, nodules, cutaneous depression, skin and subcutaneous sclerosis, dermatitis, pruritus, flushing

Other: altered taste, chills, soft-tissue induration, stinging on injection, facial edema, physical or psychological drug dependence, drug tolerance, anaphylaxis


Drug-drug. Barbiturates, first-generation (sedating) antihistamines, other sedating drugs: additive CNS depression

MAO inhibitors: unpredictable reactions

Opioids: decreased analgesic effects

Drug-diagnostic tests. Amylase, lipase: increased levels

Granulocytes, white blood cells: reduced counts

Drug-herbs. Chamomile, hops, kava, skullcap, valerian: increased CNS depression

Drug-behaviors. Alcohol use: increased CNS depression

Patient monitoring

Monitor vital signs. Watch closely for evidence of shock, dyspnea, and circulatory or respiratory depression.

• Monitor drug efficacy.

• In prolonged use, assess for signs and symptoms of drug dependence.

Patient teaching

Tell patient receiving Talacen or Talwin NX that drug is for oral use only. Life-threatening reactions may result from misusing drug by injection.

• Inform patient that withdrawal symptoms may occur if he stops taking drug suddenly after prolonged use.

• Urge patient to avoid alcohol.

• Advise patient to consult prescriber before taking other prescription drugs or over-the-counter preparations.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects him.

• Advise patient to have periodic eye exams.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, herbs, and behaviors mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


A brand name for PENTAZOCINE.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
She was diagnosed with dependence on pentazocine (fortral) in 2001.
For the last 4 years, she presented an intense suicidal ideation: "I started to pray every day to get some money to buy fortral." As she could not stop taking it, she borrowed money at 100% interest.
Several days later, she changed her mind and returned to hospital for detoxification in the hope to escape from the fortral that she came to inject in open wounds on her legs.
In 2004, she presented again an intense suicidal ideation because of the rather increased difficulty to procure fortral in drug stores--with the enforcement of the anti-drug law.