氧嗎啡酮
氧嗎啡酮是一種強效的半合成**鴉片類促效劑**，在獸醫學中主要用作鎮靜/保定劑、鎮痛劑和麻醉前給藥。 * **效力：** 按重量計算，其效力約為嗎啡的10倍。 * **心血管作用：** 對心血管系統的影響通常無臨床顯著性，使其成為心血管疾病患者相對安全的選擇。 * **組織胺釋放：** 與嗎啡或配西汀不同，靜脈注射氧嗎啡酮似乎不會引起顯著的組織胺釋放。 * **臨床要點：** 由於具有高度濫用潛力，它屬於第二級（C-II）管制藥品。雖然對中度至重度疼痛非常有效，但在獸醫臨床上，取得難易度及費用有時會成為限制因素。
作用機制: Oxymorphone acts primarily as a full agonist at **mu (μ) opioid receptors**, with some possible activity at **delta (δ) receptors**. * **Pathway:** Binds to G-protein coupled mu-opioid receptors in the CNS (limbic system, spinal cord, thalamus, midbrain) and peripheral tissues (GI tract, urinary tract) → inhibits adenylate cyclase → decreases intracellular cAMP → promotes opening of potassium channels and inhibits voltage-gated calcium channels → hyperpolarizes nociceptive neurons and inhibits the release of pain neurotransmitters (e.g., Substance P). * **Effects:** This results in profound analgesia, sedation, respiratory depression, and altered GI motility.
各物種劑量
- As a preanesthetic/analgesic · 0.05-0.1 mg/kg IM · IM · Once · may cause dysphoria or excitement, add sedative.
- As an analgesic (acute pain) · 0.05-0.1 mg/kg IM, SC or IV · IM/SC/IV · q1-3h · concomitant tranquilization recommended
- As an analgesic (acute pain) for animals with cardiovascular disease · 0.05-0.1 mg/kg IV, IM or SC · IV/IM/SC · q2-4h
- As an analgesic (acute pain) · 0.025-0.1 mg/kg IV (IM or SC) · IV/IM/SC · q2-6h
- As an analgesic (acute pain) · 0.02-0.1 mg/kg IV, IM, or SC · IV/IM/SC · q3-4h
- Analgesia · 0.05-0.2 mg/kg IV or IM · IV/IM · 2-4 times daily
- Analgesia · 0.05-0.2 mg/kg SQ or IM · SQ/IM · q8-12 hrs
- As an analgesic · 0.01-0.02 mg/kg IV · IV · Once
- As an analgesic · 0.01-0.022 mg/kg IV ; up to 15 mg total · IV · Once · divide dose into 3-4 increments and give several minutes apart
- As an analgesic · 0.02-0.03 mg/kg IM · IM · Once
- As an analgesic · 0.015-0.03 mg/kg IV · IV · Once
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
給藥途徑
禁忌症
- Hypersensitivity to narcotic analgesics
- Patients receiving monoamine oxidase inhibitors (MAOIs)
- Diarrhea caused by a toxic ingestion (until toxin is eliminated)
- Scorpion stings (Centruroides sculpturatus and C. gertschi)
不良反應
- Respiratory depression
- Bradycardia
- Decreased GI motility (constipation)
- Panting (commonly seen in dogs)
- Ataxia, hyperesthesia, and behavioral changes (cats at high dosages)
- CNS excitement (horses)
藥物相互作用
- Butorphanol, Buprenorphine, Nalbuphine · Potentially could antagonize opiate effects
- CNS Depressants · Additive CNS effects possible
- Diuretics · Opiates may decrease efficacy in CHF patients
- Monoamine Oxidase Inhibitors (MAOIs) · Extreme caution; may cause signs of opiate overdose
- Muscle Relaxants, Skeletal · Oxymorphone may enhance effects
- Phenothiazines · May antagonize analgesic effects and increase risk for hypotension
- Tricyclic Antidepressants · Oxymorphone may exacerbate the effects of tricyclic antidepressants
- Warfarin · Opiates may potentiate anticoagulant activity
監測
- Respiratory rate/depth
- CNS level of depression/excitation
- Blood pressure (especially with IV use)
- Analgesic activity
- Cardiac rate
過量
Massive overdoses may produce profound respiratory and/or CNS depression in most species. Other effects may include cardiovascular collapse, hypothermia, and skeletal muscle hypotonia. * **Antidote:** **Naloxone** is the agent of choice in treating respiratory depression. * **Management:** In massive overdoses, naloxone doses may need to be repeated. Animals should be closely observed as naloxone's effects sometimes diminish before sub-toxic levels of oxymorphone are attained. Mechanical respiratory support should be considered in cases of severe respiratory depression.
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。