Butrum 1 Injection

Indications

• Moderate to severe pain
• Preoperative analgesia
• Pain management in opioid-tolerant patients

Dosage

Children: Refer to the BNF for Children for specific dosing information in paediatric patients.

Adults: Refer to the BNF for specific adult dosing recommendations based on the condition being treated, the route of administration, and patient-specific factors.

Mechanism of action

Butorphanol primarily acts as a kappa-opioid receptor agonist and a mu-opioid receptor partial agonist. This unique mechanism allows it to provide analgesic effects while also potentially reducing the risk of respiratory depression commonly associated with traditional opioids.

Pharmacodynamics

Butorphanol exhibits a ceiling effect for respiratory depression due to its partial agonist activity at mu-opioid receptors. This characteristic makes it a safer alternative in certain patient populations. Its analgesic effects are mediated through the activation of the kappa-opioid receptors in the brain and spinal cord, leading to inhibition of pain transmission and perception.

Pharmacokinetics

Butorphanol is absorbed rapidly after administration. It has a bioavailability of approximately 60-90% when administered intranasally and around 17% when given orally. The drug undergoes extensive hepatic metabolism, primarily through cytochrome P450 enzymes. Its elimination half-life ranges from 2 to 4 hours, with its metabolites excreted mainly in the urine. Dosing adjustments may be necessary in patients with liver impairment.

Contra-indications

• Hypersensitivity to butorphanol or any of its components
• Severe respiratory depression
• Acute or severe asthma
• Known or suspected gastrointestinal obstruction
• Concurrent use of monoamine oxidase inhibitors (MAOIs)

Adverse effects

• Drowsiness
• Dizziness
• Nausea
• Vomiting
• Constipation
• Sweating
• Dry mouth
• Confusion
• Hallucinations
• Respiratory depression

Interactions

• CNS depressants may enhance the sedative effects of butorphanol
• Opioid antagonists may reduce the analgesic effect
• MAOIs may increase the risk of severe side effects

Precautions

• Use with caution in patients with a history of substance abuse
• Caution in patients with head injury or increased intracranial pressure
• Monitor for respiratory depression in elderly or debilitated patients
• Use with caution in patients with liver or kidney impairment

Pregnancy

Butorphanol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It may cause respiratory depression in the neonate if used close to delivery.

Breast-feeding

Because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue breastfeeding or to discontinue the drug, taking into account the importance of the drug to the mother.

Storage

Store at room temperature, away from light and moisture. Keep out of reach of children.

Formulations

• Injectable solution (e.g., 1 mg/mL for intravenous or intramuscular use)
• Nasal spray formulation (e.g., 4 mg/dose)