Generic Name  : Nalbuphine.

Trade Name      : Nubain.

Drug Class        : Opioid Analgesics.

Classification   :  Opioid Mixed Agonist-Antagonist.

Source              : Synthetic.

Forms of The Drug

  1. Injectable Solution: 10mg/mL, 20mg/mL.
  2. Nasal Spray.
  3. Tablet.

Mechanism of Action

The primary mechanism of action of nalbuphine is as an agonist/antagonist of the mu (μ) and kappa (κ) opioid receptors, respectively. As an agonist of the μ-receptor, nalbuphine activates the receptor to produce a reduction in pain perception. This mechanism is similar to other opioids such as morphine, oxycodone, and hydrocodone. However, nalbuphine also acts as an antagonist of the κ-receptor, which can limit the analgesic effects of the μ-receptor activation. The dual mechanism of action of nalbuphine produces several unique effects compared to other opioids. First, nalbuphine has a lower potential for respiratory depression than many other opioids, making it a safer choice for some patients. Additionally, nalbuphine is less likely to cause dependence and withdrawal symptoms compared to other opioids, though it can still produce these effects at high doses or with prolonged use.


  1. Pain management such as postoperative pain, trauma-related pain, and pain associated with cancer. also used for chronic pain management, such as pain associated with rheumatoid arthritis, osteoarthritis, and other painful conditions.
  2. Anesthesia adjunct.
  3. Labor analgesia during labor and delivery.


  1. Hypersensitivity.
  2. Respiratory depression such as those with respiratory disease or impaired respiratory function.
  3. Head injury.
  4. Liver disease.
  5. Pregnancy and breastfeeding.
  6. Concurrent use of certain medications such as other opioids, sedatives, or monoamine oxidase inhibitors (MAOIs).

Side Effects

  1. Sedation (36%).
  2. Clamminess (9%).
  3. Nausea and vomiting (6%).
  4. Dizziness (5%).
  5. Xerostomia (4%).
  6. Headache (3%).

Drug Interaction

Interaction occurs when it is given with certain drugs.

  1. Other opioids.
  2. Sedatives and hypnotics such as benzodiazepines, barbiturates, and other sedatives or hypnotics.
  3. Monoamine oxidase inhibitors (MAOIs).
  4. Alcohol.
  5. Anticholinergics.
  6. Medications that affect liver function.
  7. Medications that affect kidney function.
  8. Medications that affect heart function.


  1. Pregnancy: Category C.
  2. Lactation: It is not known whether nalbuphine is excreted in human milk. However, studies in animals have shown that nalbuphine is present in the milk of lactating rats. Due to the potential risk of adverse effects on the infant, nalbuphine should be used with caution in nursing mothers.

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