Bufigen

Quick links to important sections

Bufigen

Method of action: Analgesic, Opioid

Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Bufigen

1. Defining Bufigen: Identity and Pharmacological Class

The medicine Bufigen contains the active substance Nalbuphine Hydrochloride, a potent agent specifically used for pain management. It is classified pharmacologically as a synthetic opioid analgesic belonging to the morphinan series. This compound’s identity is defined by its unique function as a mixed opioid agonist-antagonist. This pharmacological profile is clinically recognized for providing analgesia while interacting distinctly with opioid receptors compared to pure agonists. This dual action means that Nalbuphine provides pain relief by acting as an agonist at the kappa-opioid receptors and simultaneously acting as an antagonist at the mu-opioid receptors.

2. Composition, Origin, and Pharmaceutical Form

Nalbuphine is a synthetic compound, chemically manufactured, allowing for a high degree of control over its purity and structure. As a single-ingredient product, it contains Nalbuphine Hydrochloride as the sole active component, formulated exclusively as a sterile solution for injection. The injectable preparation is designed for immediate parenteral administration, utilizing an aqueous vehicle (such as sterile water for injection) with stabilizers. This form is used for rapid action and is typically utilized in settings that require immediate pain control, such as pre- or post-operative care.

3. General Therapeutic Purpose and Action

The fundamental therapeutic purpose of this medicine is the alleviation of moderate to severe pain. Nalbuphine achieves analgesia by modulating the transmission of pain signals in the central nervous system. This action allows the medication to interrupt the body's processing of intense painful stimuli. The drug’s use is reserved for clinical situations demanding immediate and reliable pain intervention.

What side effects are possible with Bufigen?

Possible Side Effects and Safety Information

The safety profile of Bufigen (Nalbuphine Hydrochloride), a mixed opioid agonist-antagonist, is structured around adverse reactions categorized by frequency and the organ systems affected, as defined in official regulatory documents.

Adverse Reactions and Frequencies

Adverse events are formally classified based on their incidence in clinical use:

  • Very Common Reactions: The most frequently reported adverse event is sedation (drowsiness).
  • Common Reactions: These include dizziness, headache, nausea, vomiting, dry mouth, sweating, anxiety, and a feeling of unreality (dysphoria). Reactions are documented across the Nervous System, Gastrointestinal, and Psychiatric System-Organ Classes.
  • Uncommon or Rare Reactions: Less frequent but documented effects include changes in heart rate (bradycardia or tachycardia), fluctuations in blood pressure (hypertension or hypotension), chills, and seizures.

Serious Safety Considerations

Regulatory information highlights the potential for several serious reactions. The most critical risk for this class of medicine is life-threatening respiratory depression. The medication also carries a documented risk for dependence, abuse, and misuse. Furthermore, it may precipitate acute withdrawal symptoms in individuals physically dependent on pure mu-opioid agonist drugs.


Population-Specific Safety Notes

Safety statements address required caution in specific patient populations. Individuals with renal or hepatic impairment may be at an increased risk of adverse reactions due to altered drug clearance. Additionally, safety considerations are noted for older adults due to potential increased sensitivity, and for use during labor and delivery due to documented risks of fetal bradycardia and neonatal respiratory depression.

Overdose and Emergency Response

Overdose and when to seek help

Overdose of Bufigen is primarily characterized by severe Central Nervous System (CNS) depression and profound respiratory depression. Documented clinical manifestations listed in official regulatory sources include intense somnolence, sedation, stupor, and the loss of consciousness leading to coma. Physical signs commonly observed are miosis (pinpoint pupils) and cyanosis, which results from insufficient oxygenation caused by apnea (temporary cessation of breathing). The major physiological systems affected are the CNS, the respiratory system, and the cardiovascular system, which may result in circulatory collapse.

The most severe potential outcome documented is fatal respiratory depression. For any suspected overdose, regulatory authorities mandate that patients or caregivers seek immediate medical attention due to the severe and life-threatening nature of these symptoms. Emergency response requires that primary attention be focused on establishing and maintaining a patent airway and instituting pulmonary ventilation.

Regulatory information confirms that the respiratory depression caused by Bufigen overdose can be reversed by administering a specific opioid antagonist, such as Naloxone. General supportive measures are required, including continuous monitoring of vital signs, supplemental oxygen, and supportive treatment for circulatory collapse, such as the use of fluid therapy or vasopressors to address hypotension. Patients with pre-existing respiratory impairment are noted to have increased susceptibility to these adverse effects.

Therapeutic Uses of Bufigen

What Bufigen Treats: Main Uses and Benefits

Bufigen (Nalbuphine) is relevant in contexts involving heightened systemic burden, such as situations where patients experience pronounced discomfort. It is applied across therapeutic domains where additional symptomatic support is needed to address symptoms that create noticeable physiological strain. The medication is applied across therapeutic domains where short-term symptomatic assistance is needed, including support for heightened symptoms in the perioperative context and during childbirth.

The medication is generally used when symptoms related to physical discomfort become intense or disruptive, such as profound pain arising from injuries or acute illness. It provides support that helps ease the overall symptom burden, offering symptomatic relief that assists with maintaining functional stability during difficult episodes. This application contributes to easing the overall symptom load and supports the patient during difficult episodes by easing distress.

The medication is applied in scenarios where short-term symptomatic assistance is needed, often during acute or unstable symptom patterns.

Quick Fact: Symptomatic support for Acute Discomfort — This medication is commonly used across conditions presenting with acute episodes, where symptoms become temporarily overwhelming and short-term symptomatic assistance is needed.

Eligibility and Restrictions for Use

Bufigen (Nalbuphine) eligibility is strictly defined by regulatory authorities based on absolute exclusions and specific population-based restrictions.

Contraindications and Prohibited Use

Bufigen must not be used in patients with:

  • Significant Respiratory Depression or Acute/Severe Bronchial Asthma, especially in an unmonitored setting [FDA Label].
  • Known or Suspected Gastrointestinal Obstruction, including paralytic ileus [FDA Label].
  • A known Hypersensitivity (allergy) to nalbuphine or any other ingredients [FDA Label].

Restricted and Conditional Eligibility

Use requires caution and close patient monitoring in individuals with impaired renal function or hepatic impairment as drug clearance may be slowed. Patients with a head injury, increased intracranial pressure, or a history of seizure disorders also require careful consideration.

Age-Related Eligibility Restriction/Status
Pediatrics (< 18 years) Not recommended; safety and efficacy are not established [Health Canada Monograph].
Geriatrics (Older Adults) Use requires caution and often a reduced, lower starting dose due to the greater frequency of decreased organ function [Health Canada Monograph].

Pregnancy Status: Bufigen is used for obstetrical analgesia during labor, but the newborn must be monitored. Prolonged use during pregnancy can lead to Neonatal Opioid Withdrawal Syndrome [FDA Label].

What should I know about interactions with other medicines?

Bufigen Interactions with other medicines and products

The interaction profile for Bufigen is defined by official regulatory documentation, focusing primarily on pharmacodynamic interactions.

Interaction Scope
Medicinal product categories with documented interactions CNS Depressants (e.g., Benzodiazepines, General Anesthetics, other Opioids); mu-Opioid Receptor Agonists; Serotonergic Drugs.
Specific interacting medicines Alvimopan; Olanzapine/Samidorphan.
Mechanistic basis of interactions Pharmacodynamic Antagonism; Additive Pharmacodynamic Effect; Receptor Binding Competition; Potential Hepatic Metabolism.
Timing-based interaction rules Required opioid-free interval (at least 7 days for short-acting or 14 days for long-acting opioids) before initiating Olanzapine/Samidorphan.
Population-specific interaction notes Caution advised in Hepatic Impairment and Renal Impairment; increased risk of withdrawal in Opioid-Tolerant/Dependent Patients.
Interaction-related restrictions Contraindicated combinations; Alcohol and medicinal products containing alcohol must be avoided.

Official interaction statements:

  • Contraindicated Combinations: Co-administration with Olanzapine/Samidorphan is formally contraindicated. Alvimopan is contraindicated specifically in opioid-tolerant patients due to receptor binding competition.
  • CNS Depressants and Alcohol: Concomitant use with other CNS depressants, including alcohol, results in an additive pharmacodynamic effect with the documented risk of profound sedation, respiratory depression, coma, and death.
  • Opioid Antagonism: Use with mu-Opioid Receptor Agonists (e.g., morphine, fentanyl) may partially reverse or block the agonist's effects and carries a risk of precipitating acute withdrawal in opioid-dependent patients.
  • Serotonergic Risk: Co-administration with Serotonergic Drugs (including MAO Inhibitors) is documented to carry the risk of Serotonin Syndrome.

The official regulatory documents define this product's interaction structure primarily through two major pharmacodynamic interaction types: additive CNS depression with multiple substance classes and antagonistic effects with mu-opioid receptor agonists. This formal classification imposes restrictions, including explicitly contraindicated combinations and mandatory avoidance of alcohol. The documentation further establishes procedural constraints such as specific timing separation rules for certain antagonists and highlights the need for caution based on a patient's organ function.

Mechanism of Action

Bufigen acts as a selective antagonist at the P3X7 receptor, a ligand-gated ion channel expressed predominantly on osteoclasts. The selective binding of Bufigen to the extracellular domain of the P3X7 receptor competitively inhibits the binding of its endogenous agonist, adenosine triphosphate (ATP). This receptor blockade prevents the ATP-induced opening of the channel pore.

Inhibition of the P3X7-mediated channel opening subsequently leads to a sustained, low-level inhibition of Ca^2+ flux into the osteoclast cytoplasm. This reduction in intracellular calcium signaling is a key mechanistic cascade that directly modulates the osteoclast's resorptive function, leading to a reduction in their overall activity. This cellular modification is the pharmacodynamic basis for altering the balance of bone turnover and contributing to the stabilization of total bone mineral content at the systemic physiological level.

Dosage and Administration Information

How to Use Bufigen (Nalbuphine Hydrochloride)

Bufigen is an opioid analgesic administered exclusively as a sterile solution for injection in clinical settings. Its use is guided by instructions regarding the route, dose, frequency, and specific patient monitoring requirements.


Official Routes and Form of Administration

Bufigen is formulated for parenteral administration only and is not approved for oral use. It is supplied in strengths such as 10 mg/mL and 20 mg/mL. It is officially approved for use via three primary routes:

  • Intravenous (IV) Injection
  • Intramuscular (IM) Injection
  • Subcutaneous (SC) Injection

Standard Labeled Dosing and Frequency

The dosage is individually adjusted based on the patient's condition and the severity of pain, following established clinical parameters.

Indication Starting Dose (Typical Adult) Frequency & Maximum
Analgesia 10 mg (for 70 kg patient) May be repeated every 3 to 6 hours as needed. Maximum daily dose is 160 mg.
Anesthesia Supplement 0.3 mg/kg to 3 mg/kg IV (Induction) Administered over a 10-to-15-minute period (Induction).

Population-Specific Adjustments

  • Older Adults: The starting dose should be selected cautiously, typically beginning at the low end of the dosing range.
  • Renal/Hepatic Impairment: Dose reduction may be necessary and close monitoring is advised due to altered body function.
  • Duration of Use: The medicine is intended for short-term use; long-term treatment is generally not suitable.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Bufigen

Evidence for Acute, Moderate to Severe Pain

Bufigen has been studied for its use in research exploring short-term symptom changes related to acute pain requiring opioid analgesia. The core evidence comes from Randomized Controlled Trials (RCTs), where researchers examined patient-reported outcomes describing perceived discomfort. These studies describe observed symptom patterns, comparing the drug to a placebo or to other comparable opioid pain medications. The findings describe patterns observed in the studies where participants receiving the drug reported pain intensity measurements following administration. However, the follow-up durations were limited, generally covering the immediate hours or days following an event, and long-term outcomes for patients are not fully established.

Evidence in Perioperative and Obstetrical Contexts

Research has explored the use of the drug in specific clinical settings, particularly around surgery (perioperative context) and during childbirth. Studies conducted during periods of increased symptom activity focused on using the drug as an analgesic supplement or for pain relief post-procedure. Researchers monitored both maternal and neonatal variables, and findings describe patterns observed in the studies. The follow-up durations were limited to the acute period of the procedure or labor, meaning there is limited information for long-term outcomes.

Evidence in Specific Patient Populations

Research has explored the drug’s use across different age groups. Studies explored how the drug was observed in children over the age of one (pediatric patients) and older adults in pain management settings. However, data for certain groups remain insufficient. For instance, limited data exist to characterize outcomes for children under one year old.

Frequently Asked Questions (FAQ)

Common questions about Bufigen (FAQ)

Q: How quickly does Bufigen usually start to work after the first time taking it?

Official product information describes a rapid onset of pain relief, consistent with its administration by injection. The effect typically begins within 2 to 3 minutes following intravenous (IV) injection. After an intramuscular (IM) or subcutaneous (SC) injection, the onset of action is generally observed in under 15 minutes.

Q: What is the difference between Bufigen and other similar treatments for my condition?

Bufigen is classified by regulatory authorities as a mixed opioid agonist-antagonist. This means its action is dual: it works on certain pain receptors to provide relief (agonist activity) while simultaneously blocking the effects of other opioids at different receptors (antagonist activity). This unique profile distinguishes it from pure opioid agonist medicines.

Q: Is there a risk of feeling tired or drowsy when taking Bufigen?

Official information states that the most frequently reported adverse effect is sedation, which is a medical term for feeling tired or drowsy. Official product information advises that patients should be monitored for signs of excessive sedation.

Q: Are there any long-term health risks associated with taking Bufigen?

Official documents indicate that long-term use is generally not suitable, as it carries a risk of physical dependence, and discontinuation may be associated with withdrawal symptoms. The medicine is primarily intended for short-term use for pain management.

Q: Is Bufigen safe to take with common pain relievers like ibuprofen?

Regulatory documents do not specifically list non-opioid pain relievers like ibuprofen (NSAIDs) as having a formal interaction with Bufigen. However, due to the complexity of potential drug interactions, all other pain relievers should be disclosed to a healthcare provider.

Q: Can taking Bufigen with certain supplements cause an interaction?

Interactions are documented with certain classes of medicinal products, including those classified as Serotonergic Drugs. Regulatory guidelines emphasize the importance of disclosing all medications and supplements being taken, including herbal products, to prevent potential issues.

Q: Does Bufigen interact negatively with common foods or drinks?

Official product information does not document specific negative interactions with common foods. However, the regulatory documents explicitly warn that alcohol must be avoided due to a documented risk of additive effects, which can include severe sedation and respiratory depression.

Q: Is Bufigen a controlled substance?

While the active ingredient, nalbuphine, is generally not classified as a controlled substance in the United States, official regulatory warnings acknowledge a documented risk for dependence, abuse, and misuse associated with the medication.

Q: What happens if I forget to take a dose of Bufigen?

Official regulatory documents do not provide specific general instructions for a missed dose. Since this medication is administered by injection in a clinical setting, any concerns about a missed dose should be directed to the healthcare provider responsible for the treatment plan.

Q: Will Bufigen affect my ability to drive or operate machinery?

Official patient counseling advises that because the medication can cause sedation and dizziness, it may impair the ability to perform tasks requiring full coordination, such as driving or operating machinery. Caution is necessary while receiving this treatment.

Q: What information is available about Bufigen use in children?

Official regulatory documents state that the safety and effectiveness of Bufigen have not been established in pediatric patients below the age of 18 years. Due to the lack of established data, the medicine’s use in this population is generally not recommended in official guidelines.

Q: Can Bufigen be taken on an empty stomach?

Bufigen is formulated and approved only as a sterile solution for injection; it is not available in an oral form like a tablet or capsule. Since it is administered directly into the body (parenterally), its use is not dependent on or related to when a patient eats.

Q: What is the typical time frame to see the full effect of Bufigen?

Clinical studies describe that the duration of the drug’s analgesic effect typically ranges from 3 to 6 hours. This time frame represents the observed length of the pain-relieving action after a single dose.

Q: Will Bufigen interact with herbal products, such as St. John's Wort?

The medication carries a documented risk of Serotonin Syndrome when used with other serotonergic drugs. Official information suggests caution, and disclosure to a healthcare provider is important for the concurrent use of any herbal products, due to the potential for interactions.

Q: What if Bufigen doesn't seem to be working for me after a few weeks?

Official documents note that the medicine is primarily intended for short-term use. If pain relief decreases over time, this may be due to an increase in pain or the development of analgesic tolerance. The continued effectiveness of the medicine should be reevaluated regularly, as it is intended for short-term use.

Q: Is Bufigen considered safe for people with liver disease?

Official documents state that caution is advised when the initial dose is selected for patients with hepatic (liver) impairment. This is due to altered drug clearance. Close patient monitoring is noted as necessary in this population.

Q: Does Bufigen change the way my body processes other drugs?

The body’s process for breaking down Bufigen is likely to be primarily hepatic, meaning it occurs in the liver. This metabolic pathway indicates that Bufigen is processed by the same organ as other medicines, which may potentially influence the effects of other substances.

Q: How can I access the official patient information leaflet (PIL) for Bufigen?

The official Patient Information Leaflet (PIL) or prescribing information is typically provided to the patient by the dispensing facility. This information can also be accessed publicly through government resources, such as the FDA DailyMed database or Health Canada’s Drug Product Database.

Q: Do I need to get blood tests done while I am taking Bufigen?

General regulatory documents do not mandate specific blood tests for all patients receiving this medicine. However, monitoring is strongly advised for patients with existing liver or kidney impairment, and a healthcare provider may order blood tests to assess relevant organ function in those specific cases.

Q: Why do official sources sometimes use the generic name instead of Bufigen?

Government and medical sources prioritize the use of the generic name (Nalbuphine Hydrochloride) because it refers to the single, active medicinal substance. This ensures clarity, consistency, and unambiguous identification across all brand-name versions and countries.

Q: Is the active ingredient in Bufigen also used in other medicines?

Yes, Nalbuphine Hydrochloride is the active ingredient in Bufigen. It is also available as a single-ingredient generic injection used to provide the same type of pain relief.

Q: Is Bufigen suitable for vegetarians or people with certain food allergies (e.g., lactose)?

Bufigen is only available as an injectable solution, which means it does not contain common tablet ingredients like lactose. The official composition generally includes the active ingredient, water for injection, and small amounts of stabilizers.

Q: What is the research status of Bufigen? Is it a relatively new medicine?

The active ingredient in Bufigen, Nalbuphine Hydrochloride, is an established medication, with the first brand-name product containing it receiving US regulatory approval in the 1970s. Research continues to explore its use in various clinical settings.

Q: Can Bufigen cause blurry vision?

Blurred vision is one of the reported side effects listed in the official adverse reactions section for the drug.

Q: Is it normal to feel a change in appetite after starting Bufigen?

A change in appetite is not listed as a common reaction. However, common side effects do include nausea and vomiting. Official documents also note that decreased appetite can be a serious sign of a rare potential side effect, such as low adrenal gland function.

How should Bufigen be stored and disposed of?

How to Store and Dispose of Bufigen?

This section outlines the official requirements for storing and disposing of Bufigen (Nalbuphine Hydrochloride Injection), as documented in regulatory information.


Official Storage Requirements

Storage Factor Mandatory Condition
Temperature Store at Controlled Room Temperature (20^circC to 25^circC or 68^circF to 77^circF).
Environmental Protection The product must be Protected from Light and must Protect from Freezing.
Packaging Rules Keep the solution in its original container and in the carton until use.
Product Integrity Before use, the solution must be visually clear; do not use if the solution is discolored or contains any precipitate.
Child Safety Keep out of the sight and reach of children and in a secured place.

Official Disposal Protocol

As an opioid, the official disposal instructions require specific measures. Outdated or unused Bufigen should be discarded via a medicine take-back program. If a take-back program is not immediately available, the unused product must be flushed down the toilet to prevent accidental ingestion.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

Available in countries:

Equivalent of Bufigen found in:

A-Z Index: