Drug information of Butorphanol


Drug group:

A synthetic morphinan analgesic with narcotic antagonist action. It is used in the management of severe pain.

Mechanism of effect

The exact mechanism of action is unknown, but is believed to interact with an opiate receptor site in the CNS (probably in or associated with the limbic system). The opiate antagonistic effect may result from competitive inhibition at the opiate receptor, but may also be a result of other mechanisms. Butorphanol is a mixed agonist-antagonist that exerts antagonistic or partially antagonistic effects at mu opiate receptor sites, but is thought to exert its agonistic effects principally at the kappa and sigma opiate receptors.


Butorphanol blocks pain impulses at specific sites in the brain and spinal cord.


Half-life: 4.6 hr

Onset: <10 min (IV); 5-10 min (IM); within 15 min (nasal)

Duration: 3-4 hr (IV/IM); 4-5hr (nasal);

Peak effect: 0.5-1hr (IM); 4-5min (IV)

Bioavailability: 60-70% (nasal)

Protein Bound: 80%

Vd: 487 L (range: 305-901 L)

Metabolites: hydroxybutorphanol; N-dealkylation & conjugation of butorphanol & its metabolites

Metabolism: Liver (hydroxylation)

Excretion: Urine (primarily)




IV: 1 mg IV q3-4hr PRN; dosage range 0.5-2 mg q3-4hr

IM: 2 mg IM q3-4 hr; dosage range 1-4 mg q3-4hr


  • Initial: 1 mg (1 spray in 1 nostril); may repeat once after 60-90 min if inadequate pain relief
  • Depending on pain severity, by give initial dose of 2 mg (1 spray in each nostril); patient must remain recumbant; do not repeat this dose
  • Maintenance: 1 mg (1 spray in 1 nostril) q3-4hr prn

Balanced Anesthesia

2 mg IV before induction and/or 0.5-1 mg increments during anesthesia (higher dose may be required, up to 0.06 mg/kg, or 4 mg/70 kg)

Total cumulative dose varies; typically ranges between 4-12.5 mg (0.06-0.18 mg/kg)

Labor Pain

1-2 mg/dose IV/IM; may repeat PRN q4hr

Decrease dose if concomitantly used with other analgesics or CNS depressants

Do not administer within 4 hr of anticipated delivery

Preoperative & Preanesthesia

2 mg IM 60-90 minutes preop

This dose is approximately equipotent to morphine 10 mg or meperidine 80 mg


<18 years old: Not recommended


Drug abuse, emotional lability, head injury, hepatic/renal impairment, incr ICP, GI/urinary obstruction, BPH, hypothyroidism

Less risk of respiratory sedation than with pure opioid agonist

May produce withdrawal in opioid dependent pts

Avoid alcohol

Points of recommendation

Follow all directions on your prescription label. Butorphanol can slow or stop your breathing. Never use butorphanol in larger amounts, or for longer than prescribed. Tell your doctor if the medicine seems to stop working as well in relieving your pain.

Butorphanol may be habit-forming, even at regular doses. Never share this medicine with another person, especially someone with a history of drug abuse or addiction. MISUSE OF NARCOTIC MEDICINE CAN CAUSE ADDICTION, OVERDOSE, OR DEATH, especially in a child or other person using the medicine without a prescription. Selling or giving away butorphanol is against the law.

Do not stop using butorphanol suddenly after long-term use, or you could have unpleasant withdrawal symptoms. Ask your doctor how to avoid withdrawal symptoms when you stop using butorphanol.

Store butorphanol at room temperature away from moisture and heat.

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