戊酮可可鹼
戊酮可可鹼是一種合成的**甲基黃嘌呤衍生物**（結構上與茶鹼和咖啡因相關），具有獨特的血液流變學改善及免疫調節特性。 * **犬**：主要用於治療伴隨微血管受損的免疫介導性皮膚疾病，如**家族性犬皮肌炎**、耳廓邊緣皮脂漏/壞死及皮膚血管炎（如阿拉巴馬腐爛病）。也可作為異位性皮膚炎的輔助療法，並正被研究用於擴張性心肌病（DCM）。 * **馬**：作為皮膚血管炎、內毒素血症、舟狀骨病及胎盤炎的輔助治療。 * **貓**：偶爾與潑尼松龍（prednisolone）併用，以減輕與貓傳染性腹膜炎（FIP）相關的血管炎。 > **臨床提示**：由於其對組織重塑和發炎的影響需要時間，皮膚疾病的臨床療效可能需要 4 到 8 週才能顯現。
作用機制: The exact mechanisms are multifaceted, combining rheological improvement with anti-inflammatory effects: * **Phosphodiesterase (PDE) Inhibition**: Inhibits erythrocyte PDE → increases intracellular cAMP → increases erythrocyte flexibility and deformability, allowing red blood cells to navigate compromised microvasculature. * **Blood Viscosity Reduction**: Reduces plasma fibrinogen and increases fibrinolytic activity. * **Immunomodulation**: PDE inhibition in leukocytes decreases the production of inflammatory cytokines, notably **TNF-α**, reducing the negative effects of endotoxemia. * **Enzyme Inhibition**: In horses, it acts as a potent inhibitor of **matrix metalloproteinase-9 (MMP-9)** and a modest inhibitor of **MMP-2**, which may aid in preventing tissue degradation.
各物種劑量
- Vasculitis (off-label) · 15 mg/kg · PO · q12h · As directed · Rarely used in cats.
- Cutaneous vasculitis / General · 10 mg/kg q12h PO · PO · q12h · 30 days · OK to crush the sustained-release tablets and mix with molasses. If efficacy wanes with time, consider increasing the dose to 15 mg/kg PO twice daily or 10 mg/kg PO three times a day.
- Adjunctive treatment to prevent GI thrombosis · 7.5 mg/kg IV q12 hours · IV · q12h · Can be easily filtered in a 0.5 micron filter for IV use
- To reduce cytokine effects in endotoxemia · 7.5 mg/kg PO q12h · PO · q12h · Efficacy may be improved if used with flunixin
- To reduce cytokine effects in endotoxemia · 8 mg/kg PO q8h · PO · q8h
- Adjunctive treatment (experimental) of sepsis in foals · 7.5 mg/kg IV bolus, followed by a CRI of 1.5 mg/kg/hour · IV · Bolus then CRI · Has been shown to increase regional blood flow and suppress coagulation.
- Adjunctive treatment of equine pastern dermatitis · 4-8 mg/kg PO q12h · PO · q12h · Add if clinical signs do not resolve after 14 days of topical and other immunomodulating therapy
- To increase oxygenation of placenta in placentitis · 7.5 mg/kg PO q12h · PO · q12h
- To increase the circulation to the podotrochlea · 4.5-7 mg/kg PO three times daily · PO · TID
給藥途徑
禁忌症
- Intolerance or hypersensitivity to pentoxifylline or other xanthines (e.g., theophylline, caffeine, theobromine)
- Cerebral hemorrhage
- Retinal hemorrhage
- Hypersensitivity to methylxanthines (e.g., theophylline, caffeine)
- Cerebral or retinal hemorrhage
- Severe hepatic or renal impairment (use with caution)
不良反應
- Vomiting
- Inappetence
- Loose stools
- Excitement
- Nervousness
- Dizziness (humans)
- Headache (humans)
- Erythema multiforme (rare in dogs)
- Transient leukocytosis (horses IV)
- Muscle fasciculations (horses IV)
- Sweating on shoulders/flanks (horses IV)
- Mild increases in heart rate (horses IV)
- Anorexia
- Diarrhea
- Restlessness
- Tachycardia
- Tremors
藥物相互作用
- Antihypertensive drugs · May increase hypotensive effect when used concurrently
- NSAIDs · Controversial in horses; may negate beneficial effects for endotoxemia, though some studies show superior efficacy when used with flunixin
- Platelet-aggregation inhibitors (e.g., aspirin, clopidogrel) · Increased risk for bleeding
- Theophylline · Serum levels of theophylline may be increased when used concurrently · major
- Warfarin · Increased risk of bleeding; use together with enhanced monitoring and caution · moderate
- Ciprofloxacin · May increase pentoxifylline levels · moderate
- Antihypertensives · Potential for additive hypotensive effects · minor
監測
- Clinical efficacy (resolution of dermatologic or vascular signs)
- Adverse effects (GI upset, CNS signs)
- Clinical response (resolution of skin lesions/improved blood flow)
- Gastrointestinal tolerance
- Signs of bleeding
過量
Signs of overdose in humans include **flushing, seizures, hypotension, unconsciousness, agitation, fever, somnolence, GI distress, and ECG changes**. One patient who ingested 80 mg/kg recovered completely. Overdoses should be treated using standard methods of appropriate gut emptying (emesis/lavage) and supportive therapies.
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