ジメチルスルホキシド (DMSO)
**ジメチルスルホキシド (DMSO)** は、ユニークな薬理特性を持つ非常に汎用性の高い双極性非プロトン性溶媒です。獣医学では主に**フリーラジカル消去薬**および**局所抗炎症薬**として利用されます。 * **主な承認用途:** 犬および馬の外傷による急性腫脹を軽減するための局所塗布薬としてFDAに承認されています。 * **適応外使用:** 中枢神経系外傷、脳浮腫、一過性虚血状態、皮膚潰瘍、熱傷、腸管手術の補助治療、アミロイドーシス、および化学療法剤（ドキソルビシンなど）の血管外漏出による組織損傷の軽減。 * **浸透促進剤:** DMSOは、不可逆的な損傷を引き起こすことなく、無傷の皮膚や生体膜を容易に透過します。強力なキャリア（担体）として働き、他の薬物（コルチコステロイド、抗生物質、鎮痛薬など）や潜在的な毒性化合物の経皮吸収を促進します。 * **臨床上の注意点:** 非常に吸湿性が高いため、室内の空気にさらしたままにすると自己希釈されます。工業用不純物が全身循環に入るのを防ぐため、必ず医療用DMSOを使用する必要があります。
作用機序: DMSO exhibits a diverse array of pharmacological effects through multiple pathways: * **Free Radical Scavenging:** DMSO directly traps the **free radical hydroxide (OH•)**, while its primary metabolite, **dimethyl sulfide (DMS)**, traps free radical oxygen. This mechanism underpins its anti-inflammatory, cryopreservative, anti-ischemic, and radioprotective qualities. * **Enzyme Inhibition:** Inhibits **alcohol dehydrogenase** → slows the metabolism of alcohol and prevents the conversion of ethylene glycol into its toxic metabolites (making it a potential, though less common, antidote for antifreeze toxicity). * **Prostaglandin Modulation:** Enhances **Prostaglandin E (PGE)** but blocks the synthesis of **PGE2, PGF2-alpha, PGH2, and PGG2**, contributing to its analgesic and anti-inflammatory effects. * **Vascular Effects:** Provokes **histamine** release from mast cells → local vasodilation. It also decreases platelet aggregation. * **Neuromuscular:** Exhibits weak **anticholinesterase** activity.
動物種別の用量
- Acute swelling due to trauma · Liberal application should be administered topically to the skin over the affected area 2-3 times daily. Total daily dosage should not exceed 100 grams (or mL of liquid) · topical · q8-12h · Max 30 days
- Adjunctive treatment with surgical colics · 25 mg/kg IV intraoperatively and continued twice daily for the first 24-48 hours post-op. · IV · q12h · 24-48 hours · Administer slowly at 10% concentration.
- Acute rhabdomyolysis · 1 g/kg in a 10% solution of lactated Ringer's or Multisol IV or orally. · IV/PO · once · May be given in the acute stages once hydration status has been restored.
- Adjunctive treatment for laminitis · 0.1-1 g/kg IV, 2-3 times daily · IV · q8-12h · Administer slowly at 10% concentration.
- Acute swelling due to trauma · Liberal application should be administered topically to the skin over the affected area 3-4 times daily. Total daily dosage should not exceed 20 grams (or mL of liquid) · topical · q6-8h · Max 14 days
- Calcinosis cutis · Apply topically to a small area of the body initially (if extensive areas are involved) once daily; and as these areas improve, add new treatment areas. · topical · q24h · Dogs may 'feel bad' if large areas are treated initially, but do not become hypercalcemic.
- Persistent cases of hemorrhagic cystitis (secondary to cyclophosphamide tx) · 10 mL of DMSO medical grade 50% solution is diluted with 10 mL of water and instilled into bladder and removed after 20 minutes. · intravesical · once · 20 minutes
投与経路
禁忌
- Mastocytomas (due to mast cell degranulation)
- Dehydration or shock (diuretic and vasodilatory effects may exacerbate)
- Pregnancy (teratogenic at high doses in some species; use with extreme caution)
有害事象
- Local 'burning', erythema, vesiculation, and dry skin (topical)
- Garlic or oyster-like breath odor
- Lenticular changes (myopia) with chronic high doses
- Hemolysis and hemoglobinuria (IV in horses, especially at >10% concentration or rapid administration)
- Diarrhea, muscle tremors, and colic (IV in horses)
- Rare hepatotoxicity and renal toxicity
薬物相互作用
- Organophosphates / Cholinesterase Inhibitors · Avoid concurrent use due to DMSO's anticholinesterase activity.
- Mercury salts · Can cause fatal mercury intoxication if mixed and applied topically.
- Alcohol · DMSO inhibits alcohol dehydrogenase and may prolong the effects of alcohol.
- Insulin · May be potentiated by DMSO.
- Corticosteroids · May be potentiated by DMSO.
- Atropine · May be potentiated by DMSO.
- Topical toxins or other topical medications · Profound enhancement of systemic absorption of the co-administered substance, potentially leading to systemic toxicity. · major
- Dexrazoxane · DMSO may decrease the activity and efficacy of dexrazoxane; concurrent use should be discouraged. · moderate
モニタリング
- Clinical efficacy (reduction in swelling/inflammation)
- Hemoglobinuria and hematocrit (especially in horses receiving IV therapy)
- Ophthalmic exams (with high doses or chronic use in dogs to monitor for lenticular changes)
過量投与
The reported LD50 following IV dosage is approximately 4 g/kg in cats and 2.5 g/kg in dogs. **Clinical Signs of Toxicity:** * *Non-lethal doses:* Sedation and hematuria. * *Higher dosages:* Coma, seizures, opisthotonus, dyspnea, and pulmonary edema. **Treatment:** Should an acute overdosage be encountered, treat supportively.
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。