環孢素
環孢素是一種高脂溶性的多肽類藥物，最初從真菌中分離。在獸醫眼科中，它是治療犬**乾眼症 (KCS)** 和**慢性表層角膜炎 (Pannus)** 的基石療法。 除了刺激淚液分泌外，環孢素還能減少與慢性發炎相關的角膜色素沉著和肉芽組織增生。它在長期局部使用下通常非常安全，不會產生全身性的免疫抑制副作用。
作用機制: 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.
各物種劑量
- 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.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- Feline keratoconjunctivitis sicca associated with active herpes virus infection
- Feline eosinophilic keratitis (historically, though newer evidence varies, the monograph notes it is not promising)
不良反應
- Mild ocular irritation upon application
- Aggravation of ophthalmic herpes virus infections (especially in cats)
藥物相互作用
- 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
監測
- 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
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 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。