ペントキシフィリン
ペントキシフィリンは、独自の血液レオロジー改善および免疫調節特性を持つ合成**メチルキサンチン誘導体**（テオフィリンやカフェインと構造的に関連）です。 * **犬**：主に**家族性犬皮膚筋炎**、耳介辺縁脂漏症/壊死、皮膚血管炎（アラバマロットなど）といった微小血管障害を伴う免疫介在性皮膚疾患の治療に使用されます。また、アトピー性皮膚炎の補助療法としても使用され、拡張型心筋症（DCM）への応用も研究されています。 * **馬**：皮膚血管炎、エンドトキシン血症、舟状骨病、胎盤炎の補助療法として使用されます。 * **猫**：猫伝染性腹膜炎（FIP）に関連する血管炎を軽減するため、プレドニゾロンと併用されることがあります。 > **臨床のポイント**：組織のリモデリングや炎症に対する効果が現れるまで時間がかかるため、皮膚疾患における臨床的効果が見られるまでに4〜8週間かかる場合があります。
作用機序: 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.
動物種別の用量
- 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
投与経路
禁忌
- 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)
有害事象
- 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
薬物相互作用
- 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
モニタリング
- 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
過量投与
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.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。