Pentazocine; Uses, Dosage, Side Effects, Interactions

Last updated: February 7, 2026Reviewed date: February 7, 2026Reading time: 6 min read

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Pentazocine Hydrochloride is the hydrochloride salt form of pentazocine, a benzomorphan narcotic agonist-antagonist. Pentazocine hydrochloride binds to and activates kappa- and sigma-opioid receptors, resulting in sedation and analgesia. In addition, this agent antagonizes the mu-receptor. Pentazocine hydrochloride partially reverses opiate-induced cardiovascular, respiratory, and behavioral depression. Pentazocine is a synthetic opioid with...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

Key Takeaways

This article explains Mechanism of Action of Pentazocine in simple medical language.
This article explains Indications of Pentazocine in simple medical language.
This article explains Contra-Indications of Pentazocine in simple medical language.
This article explains Dosage of Pentazocine in simple medical language.

Educational health guideWritten for patient understanding and clinical awareness.

Reviewed content workflowUse writer and reviewer profiles for stronger trust.

Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
New weakness, severe pain, high fever, or symptoms after a serious injury.
Any symptom that feels urgent, unusual, or unsafe for the patient.

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

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Definition

Pentazocine Hydrochloride is the hydrochloride salt form of pentazocine, a benzomorphan narcotic agonist-antagonist. Pentazocine hydrochloride binds to and activates kappa- and sigma-opioid receptors, resulting in sedation and analgesia. In addition, this agent antagonizes the mu-receptor. Pentazocine hydrochloride partially reverses opiate-induced cardiovascular, respiratory, and behavioral depression.

Pentazocine is a synthetic opioid with both agonist and antagonist activity against opiate receptors which is used in oral and parenteral forms as an pain-relieving medicine. সহজ বাংলা: ব্যথানাশক ওষুধ।" data-rx-term="analgesic" data-rx-definition="An analgesic is a pain-relieving medicine. সহজ বাংলা: ব্যথানাশক ওষুধ।">analgesic for moderate-to-severe pain. Pentazocine has not been linked to serum enzyme elevations during therapy or to clinically apparent liver injury.

Mechanism of Action of Pentazocine

The preponderance of evidence suggests that pentazocine antagonizes the opioid effects by competing for the same receptor sites, especially the opioid mu receptor.

Pentazocine is a potent pain-relieving medicine. সহজ বাংলা: ব্যথানাশক ওষুধ।" data-rx-term="analgesic" data-rx-definition="An analgesic is a pain-relieving medicine. সহজ বাংলা: ব্যথানাশক ওষুধ।">analgesic which when administered orally in a 50 mg dose appears equivalent in analgesic effect to 60 mg (1 grain) of codeine. The onset of significant analgesia usually occurs between 15 and 30 minutes after oral administration, and the duration of action is usually three hours or longer. Onset and duration of action and the degree of pain relief are related both to dose and the severity of pretreatment pain. Pentazocine weakly antagonizes the analgesic effects of morphine and meperidine; in addition, it produces an incomplete reversal of cardiovascular, respiratory, and behavioral depression induced by morphine and meperidine. Pentazocine has about 1/50 the antagonistic activity of nalorphine. It also has sedative activity.

Indications of Pentazocine

For the relief of moderate to severe pain.
Preanesthetic medication therapy
Severe Pain
Mild Pain NOS
Moderate Pain
Pain
Sedation
Anesthesia
Labor Pain

Contra-Indications of Pentazocine

Systemic mastocytosis
Brain tumor
Untreated decreased level of thyroid hormones
Addison’s disease
Extreme loss of body water
Psychosis caused by Sudden Alcohol Withdrawal
Psychosis caused by a poisonous agent
Mood changes
Having thoughts of suicide
Addiction to a drug
Alcohol intoxication
Drug abuse
Slow heartbeat
Abnormal heart rhythm
Abnormally low blood pressure
Emphysema
Decreased lung function
Stomach or Intestinal Tract Operation
Ulcerated Colon
Inflammatory bowel disease
Constipation
Liver problems
Disease of the Gallbladder
Spasm of a bile duct tract
Kidney disease with a reduction in kidney function
Narrowing of the Tube that Empties Urine From the Bladder
Enlarged Prostate
Coma
Seizures
Shock
Can not empty bladder
Weakened Patient
High pressure within the skull
Intense Abdominal Pain
Morbid Obesity
Asthma That Is Getting Worse
Allergies to Pentazocine

Dosage of Pentazocine

Strengths: 30 mg/mL

Anesthesia

Initial dose: 30 mg IM/IV/subcutaneously; may repeat dose every 3 to 4 hours
Maximum single doses: 30 mg (IV); 60 mg (IM or subcutaneously)
Maximum daily dose: 360 mg

Pain

Initial dose: 30 mg IM/IV/subcutaneously; may repeat dose every 3 to 4 hours
Maximum single doses: 30 mg (IV); 60 mg (IM or subcutaneously)
Maximum daily dose: 360 mg

Labor Pain

Initial dose: 30 mg IM or 20 mg IV
Two or three additional 20 mg IV doses may be given at 2 to 3-hour intervals as needed when contractions become regular

Pediatric Dose for Anesthesia

Initial dose: 0.5 mg/kg IM once

Pediatric Dose for Pain

Age: 16 years or older
Initial dose: 30 mg IM/IV/subcutaneously; may repeat dose every 3 to 4 hours
Maximum single doses: 30 mg (IV); 60 mg (IM or subcutaneously)
Maximum daily dose: 360 mg

Side Effects of Pentazocine

More Common

False or unusual sense of well-being
nausea
vomiting

Common

Blistering, crusting, irritation, itching, or reddening of the skin
blue-green to black skin discoloration
bluish lips or skin
blurred vision
burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings
cold, clammy skin
confusion
cough
cracked, dry, or scaly skin
the decrease in the frequency of urination
the decrease in urine volume
depression
difficult or troubled breathing
difficulty in passing urine (dribbling)
dizziness
fainting
fast or slow heartbeat
fast, weak pulse
flushed skin
hardening or thickening of the skin
pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।" data-rx-term="headache" data-rx-definition="Headache means pain in the head or upper neck. সহজ বাংলা: মাথাব্যথা।">headache
increased sweating
irregular, fast, slow, or shallow breathing
lightheadedness
nervousness
pain, redness, or sloughing of the skin at the injection site

Rare

Change in taste
confusion about identity, place, and time
constricted, pinpoint, or small pupils (black part of the eye)
double vision
seeing double seeing, hearing, or feeling things that are not there
stomach cramps
trouble sleeping
uncontrolled eye movements

Drug Interactions of Pentazocine

Pentazocine may interact with following drugs, supplements & may change the efficacy of drugs

alcohol
anesthetics
antihistamines (e.g., cetirizine, dimenhydrinate, diphenhydramine, hydroxyzine)
antipsychotic medications (e.g., olanzapine, quetiapine, risperidone)
baclofen
barbiturates (e.g., phenobarbital, secobarbital)
benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
benztropine
brimonidine
bupropion
cyclobenzaprine
dantrolene
desmopressin
dextroamphetamine
diamorphine
diphenoxylate
flavoxate
gabapentin
guanfacine
ipratropium
methadone
methocarbamol
mirtazapine
monoamine oxidase inhibitors (e.g, tranylcypromine, phenelzine, moclobemide) taken within the past 14 days
octreotide
orphenadrine
other narcotic analgesics (e.g., codeine, morphine)
oxybutynin
phenothiazines (e.g., perphenazine, thioridazine)
pregabalin
sedatives and tranquilizers
seizure medications (e.g., carbamazepine, lamotrigine, phenytoin, primidone)
selective serotonin reuptake inhibitors (SSRIs; e.g., paroxetine, fluoxetine, citalopram)
thiazide diuretics (e.g., hydrochlorothiazide, indapamide)
tiotropium
tolcapone
tolterodine
tricyclic antidepressants (e.g., amitriptyline, desipramine, imipramine)
zopiclone

Pregnancy Category

TGA pregnancy category – C
FDA pregnancy category – N (Not assigned )

Pregnancy

This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Lactation

This medication passes into breast milk. If you are a breast-feeding mother and are taking pentazocine, it may affect your baby. Talk to your doctor about whether you should continue breastfeeding. The safety and effectiveness of using this medication have not been established for children. Accidental ingestion of this medication by children may lead to severe and even f

References

Pentazocine; Uses, Dosage, Side Effects, Interactions

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

Write when the problem started and how it changed.
Bring old prescriptions, investigation reports, and current medicines.
Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

What is the most likely cause of my symptoms?
Which danger signs mean I should go to hospital quickly?
Which tests are necessary now, and which can wait?
How should I take medicines safely and what side effects should I watch for?
When should I come for follow-up?

Tests to discuss

Vital signs: temperature, pulse, blood pressure, oxygen saturation
Basic physical examination by a clinician
CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

Avoid heavy lifting, sudden bending, and prolonged bed rest.
Use comfortable posture and gentle movement as tolerated.
Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

Do not start antibiotics without a proper medical decision.
Do not use steroid tablets or injections casually for quick relief.
Do not delay emergency care because of home remedies.

Get urgent help if

Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.

Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider

Tests to discuss with doctor

Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
Relevant blood, urine, imaging, or specialist tests only after clinical assessment

Questions to ask

What is the most likely cause of my symptoms?
Which warning signs mean I should go to emergency care?
Which tests are really needed now?
Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Go to emergency care if you notice:

Severe or rapidly worsening symptoms
Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration

Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.

Step 1
Check danger signs first

If danger signs are present, seek emergency care and do not wait for online information.
Step 2
Record the symptom story

Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.
Step 3
Visit a qualified clinician

A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.
Step 4
Do only useful tests

Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.
Step 5
Follow up and return early if worse

If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips

Take a written symptom diary and all previous prescriptions/test reports.
Do not hide medicines already taken, even herbal or over-the-counter medicines.
Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

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Write your symptom story. A health professional or site editor can review it before any answer is prepared. This box is not for emergency care.

Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

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Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

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