STADOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for STADOL (STADOL).
Partial agonist at mu-opioid receptors and agonist at kappa-opioid receptors in the CNS, altering pain perception and emotional response to pain.
| Metabolism | Primarily hepatic via CYP3A4 and conjugation; forms active metabolite (pentazocine) and inactive metabolites. |
| Excretion | Renal: 85-90% as unchanged drug and metabolites (primarily as glucuronide conjugates); Fecal: <10%; Biliary: minimal |
| Half-life | Terminal elimination half-life: 2.5-4 hours; clinically, prolonged in hepatic impairment (up to 10-12 hours) and elderly |
| Protein binding | 80-85% bound primarily to albumin, also to alpha-1-acid glycoprotein |
| Volume of Distribution | 3-5 L/kg; large Vd indicates extensive tissue distribution, with CNS penetration |
| Bioavailability | Intramuscular: ~80%; Oral: ~17% (poor oral bioavailability due to extensive first-pass metabolism) |
| Onset of Action | Intravenous: 1-2 minutes; Intramuscular: 10-15 minutes; Oral: 30-60 minutes (not clinically used) |
| Duration of Action | Analgesic duration: 3-4 hours IM/IV; respiratory depression may persist longer (up to 6 hours); duration increased in hepatic dysfunction |
Butorphanol tartrate 1-2 mg IV or IM every 3-4 hours as needed for pain; alternatively, 0.5-1 mg IV every 3-4 hours. For nasal spray: 1 mg (one spray) in one nostril, may repeat in 60-90 minutes if needed; then 1 mg every 3-4 hours as needed.
| Dosage form | INJECTABLE |
| Renal impairment | For creatinine clearance (CrCl) < 30 mL/min: reduce dose to half the usual recommended dose and increase dosing interval to every 6-8 hours. For CrCl 30-50 mL/min: consider extending interval to every 6 hours. Avoid use in severe renal impairment (CrCl < 15 mL/min) if possible. |
| Liver impairment | In Child-Pugh Class B (moderate impairment): reduce initial dose by 50% and titrate cautiously. For Child-Pugh Class C (severe impairment): avoid use or use with extreme caution, using the lowest effective dose; consider alternative therapy. No specific dose adjustment for Child-Pugh A. |
| Pediatric use | Not recommended for use in children < 18 years of age due to lack of safety and efficacy data. For adolescents (if used): 0.5-1 mg IV/IM every 3-4 hours as needed, based on weight (0.01-0.02 mg/kg/dose); maximum 2 mg per dose. Nasal spray not recommended. |
| Geriatric use | In patients > 65 years: initial dose should be reduced to 0.5 mg IV/IM every 4-6 hours, and titrate slowly due to increased sensitivity and risk of respiratory depression. For nasal spray: initial 1 mg, then extended interval (every 4-6 hours) and monitor closely. Maximum single dose: 1 mg IV/IM. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for STADOL (STADOL).
| Breastfeeding | Butorphanol is excreted into breast milk; M/P ratio is approximately 0.7 – 1.0. Concentrations are low but may cause sedation or respiratory depression in the infant; AP rated by AAP as 'maternal medication usually compatible with breastfeeding' with caution. Monitor infant for drowsiness, feeding difficulty, or respiratory depression. |
| Teratogenic Risk | FDA Category C/D (if used for prolonged periods or high doses near term). First trimester: Limited data; potential risk of congenital malformations not definitively established; avoid if possible. Second trimester: Use only if clearly needed; no well-documented teratogenicity. Third trimester: Use may cause neonatal withdrawal syndrome (irritability, crying, tremors, hypertonia, seizures) and respiratory depression if given near delivery; prolonged use may lead to physical dependence in fetus. |
■ FDA Black Box Warning
Risk of respiratory depression, especially in elderly, cachectic, or debilitated patients. Risk of opioid addiction, abuse, and misuse. Life-threatening respiratory depression can occur at any time. Accidental ingestion, especially in children, can be fatal. Prolonged use during pregnancy can result in neonatal opioid withdrawal syndrome.
| Serious Effects |
Hypersensitivity to butorphanol or tartrazine, use of MAOIs within 14 days, severe asthma or respiratory insufficiency, gastrointestinal obstruction, suspected surgical abdomen.
| Precautions | Respiratory depression, CNS depression, dependency, opioid-induced hyperalgesia, increased intracranial pressure, biliary tract spasm, seizure risk, severe hypotension, adrenal insufficiency, androgen deficiency. |
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| Fetal Monitoring | Monitor maternal respiratory rate, oxygen saturation, and level of sedation; monitor fetal heart rate during labor and delivery if used for analgesia; assess neonatal Apgar scores and respiratory status after delivery; monitor for signs of neonatal withdrawal if used chronically. |
| Fertility Effects | No known adverse effects on human fertility; animal studies show no impairment of fertility at clinically relevant doses. |