レバミゾール
レバミゾールはイミダゾチアゾール誘導体であり、主に大動物における抗線虫薬として利用され、歴史的には小動物におけるミクロフィラリア駆除薬および免疫賦活剤として使用されてきました。 **臨床上のポイント：** * **小動物での使用減少：** 治療域が狭く、より安全で有効な駆虫薬（マクロライド系、ベンズイミダゾール系など）が登場したため、現代の犬猫の臨床ではほとんど使用されません。 * **大動物での有用性：** 牛、羊、豚においては依然として価値のある広域スペクトル駆虫薬であり、特に胃腸管および肺の線虫に有効ですが、寄生虫の薬剤耐性が世界的な懸念となっています。 * **免疫調節作用：** 細胞性免疫を刺激する独自の能力により、特に免疫不全の患者において、慢性感染症、免疫介在性疾患、特定の腫瘍に対する補助療法として適応外使用されることがあります。
作用機序: **Antiparasitic Action:** Levamisole acts as a cholinergic agonist at **nicotinic acetylcholine receptors** on the nematode muscle. * Receptor activation → continuous depolarization → **spastic paralysis** of the worm. * The paralyzed nematodes are subsequently expelled alive from the host's gastrointestinal or respiratory tract. * At higher concentrations, it interferes with nematode carbohydrate metabolism by blocking **fumarate reduction** and **succinate oxidation**. **Immunostimulant Action:** The exact mechanism is not fully elucidated. It is believed to: * Restore cell-mediated immune function in peripheral **T-lymphocytes**. * Stimulate phagocytosis and chemotaxis by **monocytes and macrophages**. * Effects are generally more pronounced in immunocompromised animals rather than healthy ones.
動物種別の用量
- For removal of mature and immature Dictyocaulus vivapurus · 8 mg/kg PO · PO · Once
- For treatment of susceptible nematodes · 7.5 mg/kg PO · PO · Once
- For removal of mature and immature Dictyocaulus vivapurus · 8 mg/kg PO · PO · Once
- For treatment of susceptible nematodes · 7.5 mg/kg PO · PO · Once
- For the treatment of lungworms · 20-40 mg/kg PO every other day for 5-6 treatments · PO · q48h · 5-6 treatments
- For Aelurostrongylus abstrusus (lungworms) · 100 mg PO daily every other day for 5 treatments; give atropine (0.5 mg SC, 15 minutes before administering); or 15 mg/kg PO every other day for 3 treatments, then 3 days later: 30 mg/kg PO, then 2 days later: 60 mg/kg. · PO · Varies · Varies
- For Capillaria aerophilia (lungworms) · 4.4 mg/kg SC for 2 days, then 8.8 mg/kg once 2 weeks later; or 5 mg/kg PO once daily for 5 days, followed by 9 days of no therapy, repeat two times · SC/PO · Varies · Varies
- For the treatment of lungworms · 25 mg/kg every other day for 10-14 days · PO · q48h · 10-14 days
- For Capillaria aerophilia (lungworms) · 10 mg/kg PO once daily for 5 days; repeat in 9 days · PO · q24h · 5 days
投与経路
禁忌
- Lactating dairy animals (not approved)
- Severely debilitated animals
- Patients with significant renal or hepatic impairment
- Cats with FIV or FIP (and likely ineffective in FeLV)
- Use as a dirofilarial adulticide
- Intravenous (IV) administration (never recommended)
- Intramuscular (IM) administration in birds (avoid if possible)
有害事象
- Cattle: Muzzle foaming, hypersalivation, excitement, trembling, lip-licking, head shaking, injection site swelling
- Sheep/Goats: Transient excitability, depression, hyperesthesia, salivation, stinging upon SC injection
- Swine: Salivation, muzzle foaming, coughing/vomiting (especially if infected with lungworms)
- Dogs: GI disturbances (vomiting, diarrhea), neurotoxicity (panting, shaking, agitation), immune-mediated anemia, agranulocytosis, dyspnea, pulmonary edema, immune-mediated skin eruptions (erythema multiforme, toxic epidermal necrolysis), lethargy
- Cats: Hypersalivation, excitement, mydriasis, vomiting
薬物相互作用
- Aspirin · Levamisole may increase salicylate levels
- Chloramphenicol · Fatalities have been reported after concomitant administration; avoid using these agents together
- Cholinesterase-inhibiting drugs (e.g., organophosphates, neostigmine) · Could theoretically enhance the toxic effects of levamisole; use together with caution
- Nicotine-like compounds (e.g., pyrantel, morantel, diethylcarbamazine) · Could theoretically enhance the toxic effects of levamisole; use together with caution
- Warfarin · Increased risk for bleeding
モニタリング
- Clinical efficacy (fecal exams, resolution of clinical signs)
- Adverse effects/toxicity observation
過量投与
Signs of levamisole toxicity often mimic those of **organophosphate toxicity** due to its cholinergic effects. * **Clinical Signs:** Hypersalivation, hyperesthesias, irritability, clonic seizures, CNS depression, dyspnea, defecation, urination, and collapse. Acute overdosage can result in death due to respiratory failure. Cardiac arrhythmias may also be seen. * **Avian Toxicity:** In pet birds, 40 mg/kg SC is reported as a toxic dose. IM injections may cause more severe toxicity. Signs include depression, ataxia, leg/wing paralysis, mydriasis, regurgitation, and death. * **Treatment:** Primarily supportive, as animals generally recover within hours of dosing. If respiratory failure occurs, institute artificial ventilation with oxygen until recovery. For recent oral ingestion, emptying the gut and/or administering activated charcoal with cathartics may be indicated. * **Warning:** Intravenous (IV) administration is particularly hazardous and is never recommended.
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。