STADOL PRESERVATIVE FREE
Clinical safety rating
cautionComprehensive clinical and safety monograph for STADOL PRESERVATIVE FREE (STADOL PRESERVATIVE FREE).
Butorphanol is a synthetic agonist-antagonist opioid analgesic that exerts its effects primarily through binding to kappa-opioid receptors and, to a lesser extent, mu-opioid receptors, producing analgesia and sedation. It also has partial antagonist activity at mu receptors.
| Metabolism | Primarily metabolized in the liver to hydroxylbutorphanol via CYP3A4 and other enzymes. |
| Excretion | Primarily hepatic metabolism (glucuronidation) to inactive metabolites; renal excretion accounts for <5% unchanged drug. Approximately 70% of dose excreted in urine as metabolites, 20% in feces. |
| Half-life | Terminal elimination half-life is 2.5–3.3 hours in adults; prolonged to 4–6 hours in elderly or hepatic impairment. |
| Protein binding | Approximately 76–80% bound to serum proteins, primarily albumin and α1-acid glycoprotein. |
| Volume of Distribution | Volume of distribution is 1.2–1.7 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Intramuscular: 70–80%; Subcutaneous: similar to IM. Oral: <5% due to extensive first-pass metabolism. |
| Onset of Action | Intravenous: 2–3 minutes; Intramuscular: 10–15 minutes. |
| Duration of Action | IV: 3–4 hours; IM: 4–6 hours. Duration may be shorter with rapid IV administration due to redistribution. |
| Molecular Weight | 327.46 |
0.5–2 mg intravenously or intramuscularly every 3–4 hours as needed for pain. Alternatively, 1–2 mg as a single dose, may repeat in 30–60 minutes if needed.
| Dosage form | INJECTABLE |
| Renal impairment | For GFR 15–29 mL/min: reduce dose by 50% or increase dosing interval to every 6–8 hours. For GFR <15 mL/min: use with caution, reduce dose by 75% or administer every 8–12 hours. Hemodialysis: no supplemental dosing; not dialyzable. |
| Liver impairment | Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% or extend interval to every 6 hours. Child-Pugh Class C: avoid use; if necessary, reduce dose by 75% and monitor closely. |
| Pediatric use | Children ≥12 years: 0.5–2 mg intravenously or intramuscularly every 3–4 hours as needed. Children 2–12 years: 0.1–0.2 mg/kg/dose intravenously or intramuscularly every 3–4 hours as needed (max single dose 2 mg). Children <2 years: not recommended. |
| Geriatric use | Elderly patients (≥65 years): initiate at 0.5 mg intravenously or intramuscularly every 4–6 hours; increase cautiously based on response and tolerability. Reduce total daily dose by 25–50% compared to younger adults. |
| 1st trimester | Avoid due to lack of safety data. |
| 2nd trimester | Avoid; potential for maternal dependence and neonatal withdrawal. |
| 3rd trimester | Avoid; risk of neonatal respiratory depression and withdrawal syndrome. |
Clinical note
Comprehensive clinical and safety monograph for STADOL PRESERVATIVE FREE (STADOL PRESERVATIVE FREE).
| Placental transfer | Crosses placenta; documented in human studies. |
| Breastfeeding | Excreted in breast milk in low concentrations. Use caution due to potential for infant sedation and respiratory depression. Consider risk-benefit. |
| Lactation Rating | L3 - Limited Data |
| Teratogenic Risk | Pregnancy Category C. First trimester: No adequate studies; potential risk based on animal data at 2.5-5 times human dose. Second trimester: Same as first; prolonged use may lead to neonatal opioid withdrawal syndrome. Third trimester: Risk of neonatal respiratory depression if administered near term; may cause opioid withdrawal in newborn after chronic use. |
| Fetal Monitoring | Monitor maternal vital signs (respiratory rate, blood pressure, heart rate); fetal heart rate during labor; observe neonate for respiratory depression and withdrawal symptoms if used near term or prolonged use. |
| Fertility Effects | May impair fertility in males and females based on animal studies (reduced conception rates, altered estrous cycle); human data insufficient. |
■ FDA Black Box Warning
Risk of opioid addiction, abuse, and misuse; life-threatening respiratory depression; accidental ingestion; neonatal opioid withdrawal syndrome; risks from concomitant use with benzodiazepines or other CNS depressants; and risk of abuse and dependence.
| Serious Effects |
Hypersensitivity to butorphanol or any componentSevere respiratory depressionAcute or severe bronchial asthmaSuspected or known gastrointestinal obstructionUse of MAO inhibitors within 14 days
| Precautions | Concomitant use with CNS depressants (e.g., benzodiazepines) increases risk of sedation, respiratory depression, coma, and death, Risk of respiratory depression, especially in elderly, cachectic, or debilitated patients, Physical and psychological dependence with chronic use, May increase intracranial pressure in patients with head injury, Risk of hypotension in hypovolemic patients, May impair ability to perform hazardous tasks, Use in renal or hepatic impairment requires dose adjustment |
| Food/Dietary | No significant food interactions. Avoid alcohol consumption. |
| Clinical Pearls | Stadol (butorphanol) preservative-free is for IV/IM use only; not intended for epidural or intrathecal administration due to potential neurotoxicity from the formulation. Onset of analgesia is rapid (within minutes IV). Butorphanol has ceiling effect on respiratory depression, making it safer than full mu agonists in equianalgesic doses. It can cause dysphoric reactions, especially in opioid-naive patients. Use with caution in patients with hepatic or renal impairment. |
| Patient Advice | This medication can cause drowsiness, dizziness, or lightheadedness; avoid driving or operating heavy machinery until you know how it affects you. · Do not drink alcohol or take other central nervous system depressants (e.g., benzodiazepines, other opioids) while using this medicine. · Report any severe nausea, vomiting, confusion, or hallucinations to your healthcare provider. · Butorphanol can be habit-forming; use only as prescribed. · If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor before use. |
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