托吡卡胺
托吡卡胺是一種合成的短效抗膽鹼藥物，主要用於散瞳和睫狀肌麻痺。由於其起效快（20-30分鐘）且作用時間短，是眼內檢查的首選散瞳劑。 > **臨床提示：** 其散瞳效果優於睫狀肌麻痺效果，因此在緩解葡萄膜炎引起的睫狀肌痙攣方面不如阿托品有效。
作用機制: Tropicamide acts as a competitive antagonist of acetylcholine at muscarinic receptors. **Acetylcholine inhibition** at the iris sphincter muscle → relaxation of the sphincter → **mydriasis** (pupil dilation). **Acetylcholine inhibition** at the ciliary body muscles → paralysis of accommodation → **cycloplegia**.
各物種劑量
- Mydriasis and cycloplegia for intraocular examination · 1 drop per eye · topical · repeat after 20-30 min if necessary · Duration of action is 2-12 hours.
- Mydriasis and cycloplegia for intraocular examination · 1 drop per eye · topical · repeat after 20-30 min if necessary · Duration of action is 4-9 hours. May cause salivation.
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
- Glaucoma (may increase intraocular pressure)
不良反應
- Salivation (particularly in cats, though less marked than with atropine)
- Transient stinging upon application
- Photophobia (due to pupil dilation)
監測
- Intraocular pressure (IOP)
- Pupillary light reflex
- Resolution of mydriasis
過量
Systemic toxicity is rare with standard topical ophthalmic use. However, excessive administration or ingestion could theoretically lead to systemic anticholinergic signs such as **tachycardia**, **dry mucous membranes**, **ileus**, and **urinary retention**. Treatment is generally supportive.
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。