丁丙諾啡
丁丙諾啡在獸醫學中是一種用途廣泛的**鴉片類部分促效劑**。主要用於控制小動物的輕至中度急性疼痛，並常與 α-2 促效劑及解離型麻醉劑合併用於短效保定「雞尾酒」配方中。 * **臨床要點**：丁丙諾啡在標準劑量下具有「天花板效應（ceiling effect）」，意味著超過一定劑量後，可能無法產生額外的鎮痛效果，甚至在理論上可能降低鎮痛效力。 * **貓科優勢**：貓的口腔 pH 值偏鹼性，這使得丁丙諾啡具有高度脂溶性，從而實現極佳的**經口腔黏膜（OTM）/ 頰黏膜吸收**。在貓身上，頰黏膜給藥的生物可用率幾乎與肌肉注射相當，是居家術後疼痛管理的實用途徑。 * **作用時間**：與純 mu-促效劑（如吩坦尼或美沙酮）相比，其起效時間較長，但鎮痛持續時間顯著更長（通常為 6-8 小時，最長可達 12 小時）。 * **法規**：本品屬於管制藥品。
作用機制: Buprenorphine exerts its analgesic effects by acting as a **partial agonist at the mu (μ) opioid receptor** and an **antagonist at the kappa (κ) opioid receptor** in the central nervous system. * **High Affinity, Slow Dissociation**: It binds to the μ-receptor with an affinity approximately 30 times greater than morphine. This tight binding → prolonged duration of action. * **Receptor Competition**: Because of its high affinity, it can displace pure μ-agonists from the receptor, potentially antagonizing their analgesic effects while reversing their sedative and respiratory depressant effects. * **Naloxone Resistance**: Its slow dissociation from the receptor makes it notoriously difficult to fully reverse with standard doses of the opioid antagonist **naloxone**; high doses of naloxone or the use of doxapram may be required in cases of severe respiratory depression.
各物種劑量
- Analgesia · 0.005-0.02 mg/kg IM, IV or SC q6-12h · IM, IV, SC · q6-12h
- Analgesia · 2-4 micrograms/kg/hour · IV · continuous infusion
- Analgesia · 0.005-0.03 mg/kg IV, IM, SC, epidural · IV, IM, SC, epidural
- Analgesia · 0.006-0.02 mg/kg IV, IM, SQ · IV, IM, SQ · 6-12 hours · Relatively effective analgesic, but may be difficult to reverse with naloxone if untoward effects are seen.
- Analgesia · 0.02 mg/kg · IV, IM, SC · q6h · SC route is listed in historical dosing but text notes it is not recommended due to potentially lower efficacy compared to IM/IV.
- Analgesia · 0.01-0.05 mg/kg SC or IM 2-3 times daily · SC, IM · 2-3 times daily
- Analgesia · 0.01-0.03 mg/kg IM, IV, Buccal · IM, IV, Buccal · up to 6 hours · Buccal use is well accepted by cats.
- Analgesia · 0.01-0.03 mg/kg PO transmucosally (squirted directly into the mouth) q8h · PO transmucosal · q8h
- Analgesia · 0.01-0.03 mg/kg IM, IV, SC q6-8h; 0.01-0.03 mg/kg PO q6-12h · IM, IV, SC, PO · q6-12h
- Analgesia · 1-3 micrograms/kg/hour · IV · continuous infusion
給藥途徑
禁忌症
- Known hypersensitivity to buprenorphine
不良反應
- Respiratory depression (rare but significant)
- Sedation
- Urine retention or difficulty voiding (particularly with high IV or epidural doses)
- Excitement (horses)
- Diminished gut sounds (horses)
- Vomiting (rare in cats)
藥物相互作用
- Local Anesthetics (mepivacaine, bupivacaine) · May be potentiated by concomitant use of buprenorphine
- Anticonvulsants (phenobarbital, phenytoin) · May decrease plasma buprenorphine levels
- Benzodiazepines · Case reports of humans developing respiratory/cardiovascular/CNS depression; use with caution
- CNS Depressants (anesthetics, antihistamines, phenothiazines, barbiturates, alcohol) · May cause increased CNS or respiratory depression when used with buprenorphine
- Erythromycin · Can increase plasma buprenorphine levels
- Fentanyl (and other pure opiate agonists) · Buprenorphine may potentially antagonize some analgesic effects, but may also reverse some sedative and respiratory depressant effects
- Halothane · Potentially can increase buprenorphine effects
- Azole Antifungals (ketoconazole, itraconazole, fluconazole) · Can increase plasma buprenorphine levels
- Monoamine Oxidase Inhibitors (selegiline, amitraz) · Possible additive effects or increased CNS depression
- Naloxone · May reduce analgesia associated with high dose buprenorphine
- Pancuronium · If used with buprenorphine may cause increased conjunctival changes
- Rifampin · Potentially decrease plasma buprenorphine concentrations
監測
- Analgesic efficacy
- Respiratory status
- Cardiac status
過量
Buprenorphine has a very high index of safety (ratio of lethal dose to effective dose is at least 1000:1 in rodents). Life-threatening acute overdoses are rare in veterinary medicine, but clinical signs are common. * **Clinical Signs (Dogs)**: Vocalization, ataxia, hypersalivation, hypothermia, and lethargy. * **Treatment**: Supportive care. In cases of acute overdose causing severe respiratory or cardiac effects, **naloxone** and **doxapram** are suggested. > **Note**: Due to buprenorphine's extremely high affinity for the mu-receptor, standard doses of naloxone may be ineffective; very high doses of naloxone may be required to reverse respiratory depression.
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