シクロスポリン
シクロスポリンは、真菌から分離された高脂溶性のポリペプチド薬です。獣医眼科において、犬の**乾性角結膜炎（KCS、ドライアイ）**および**慢性表層角膜炎（パンヌス）**の治療における第一選択薬です。 涙液分泌を刺激するだけでなく、慢性炎症に伴う角膜の色素沈着や肉芽形成を軽減します。長期の局所投与でも全身性の免疫抑制の副作用を引き起こすことなく、一般的に安全に使用できます。
作用機序: Cyclosporine is a **calcineurin inhibitor**. It binds to cyclophilin within T-lymphocytes, inhibiting the enzyme calcineurin → prevents dephosphorylation of Nuclear Factor of Activated T-cells (NFAT) → **blocks transcription of interleukin-2 (IL-2)** and other inflammatory cytokines. In the eye, this halts local inflammatory mediator production, arresting self-perpetuating lacrimal adenitis. It also acts as a **prolactin analog**, fitting onto lacrimal prolactin receptors to directly stimulate tear production. Furthermore, it increases conjunctival mucin stores, improving the overall quality of the tear film.
動物種別の用量
- Keratoconjunctivitis sicca (KCS) · Not recommended · topical ophthalmic · Preliminary results have not been promising; often aggravates ophthalmic herpes virus infections.
- Keratoconjunctivitis sicca (KCS) · 0.2% ointment · topical ophthalmic · twice daily (up to 3 times a day initially in difficult cases) · Life-long · 3-8 weeks of therapy are necessary before a dramatic increase in the Schirmer tear test becomes evident.
- German Shepherd Pannus (chronic superficial keratitis) · 0.2% ointment · topical ophthalmic · twice daily · Life-long · Preferred over chronic topical corticosteroids due to lack of systemic side effects.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Feline keratoconjunctivitis sicca associated with active herpes virus infection
- Feline eosinophilic keratitis (historically, though newer evidence varies, the monograph notes it is not promising)
有害事象
- Mild ocular irritation upon application
- Aggravation of ophthalmic herpes virus infections (especially in cats)
薬物相互作用
- Itraconazole · Inhibits cytochrome P450 metabolism of ciclosporin, increasing blood concentrations up to five-fold. Dose reduction (halving dose or doubling interval) is required. · major
- Ketoconazole · Inhibits cytochrome P450 metabolism of ciclosporin, significantly increasing blood concentrations. · major
- Diltiazem · Competitively inhibits enzymes involved in ciclosporin metabolism, increasing serum levels. · moderate
- Doxycycline · Inhibits enzymes involved in ciclosporin metabolism, increasing serum levels. · moderate
- Aminoglycosides · Increased risk of nephrotoxicity; concomitant use is not recommended. · major
- NSAIDs · Increased risk of nephrotoxicity; concomitant use is not recommended. · major
- Quinolones · Increased risk of nephrotoxicity; concomitant use is not recommended. · moderate
- Trimethoprim/Sulphonamides · Increased risk of nephrotoxicity; concomitant use is not recommended. · moderate
- ACE inhibitors · Increased risk of hyperkalaemia. · moderate
- Macrocyclic lactones (e.g., ivermectin, milbemycin) · Ciclosporin inhibits MDR1 P-glycoprotein, decreasing the efflux of macrocyclic lactones from the blood-brain barrier, potentially resulting in CNS toxicity. · major
モニタリング
- Schirmer Tear Test (STT) after 1 month of therapy, then periodically
- Fluorescein staining to monitor for corneal ulceration
- Resolution of corneal pigmentation and neovascularization
過量投与
Systemic toxicity has **not** been noted in dogs given this drug chronically via the topical ophthalmic route. Even if 100% of the ophthalmic dose were absorbed, it is well below the systemic therapeutic/toxic dose.
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。