描述
行動
藥理作用：左氧氟沙星是氧氟沙星（L型）的光學異構體，其抗菌活性是氧氟沙星的2倍。
作用機轉：左氧氟沙星的主要作用機轉是抑制細菌DNA旋轉酶的活性。其作用比氧氟沙星強2倍。最低抑菌濃度（MIC）與最低殺菌濃度（MBC）無差異，顯示其具有殺菌作用。形態學觀察也顯示了 MIC 周圍的溶菌現象。 微生物學：抗菌活性：左氧氟沙星對引起眼科感染的微生物發揮廣譜有效抗菌活性，包括革蘭氏陽性菌[葡萄球菌屬、鏈球菌屬（包括肺炎鏈球菌）、微球菌屬、腸球菌屬、棒狀桿菌屬等] 、革蘭氏陰性菌[假單胞菌屬(包括綠膿桿菌)、嗜血桿菌屬、卡他莫拉氏菌屬、莫拉氏菌屬、沙雷氏菌屬、克雷伯氏菌屬、變形桿菌屬、不動桿菌屬等]及厭氧菌(痤瘡丙酸桿菌等) ）。 左氧氟沙星對外眼部感染患者中鑑定的每種細菌和臨床分離細菌的標準菌株的抗菌活性約為氧氟沙星的兩倍（體外）。對家兔實驗性綠膿桿菌角膜炎 的影響：左氧氟沙星眼藥水可有效預防家兔 實驗性綠膿桿菌角膜炎。
適應症/用途
由左氧氟沙星敏感菌株引起的下列感染：葡萄球菌、鏈球菌、肺炎鏈球菌、微球菌、腸球菌、棒狀桿菌、假單胞菌、綠膿桿菌、嗜血桿菌[流感嗜血桿菌、埃及嗜血桿菌、(Koch-Weeks)芽孢桿菌）]、卡他莫拉氏菌、莫拉氏菌（莫拉克斯-阿克森菲爾德芽孢桿菌）、沙雷氏菌、克雷伯菌、變形桿菌、不動桿菌、腸桿菌、痤瘡丙酸桿菌：瞼緣炎、麥粒腫、淚囊炎、結膜炎、瞼板腺炎、角膜炎、角膜潰瘍和術後感染。
劑量/使用說明
僅供眼科使用。
一般情況下，每次滴1滴，每日3次。可根據患者症狀調整劑量。 給藥方法：給藥時，應指導患者不要將瓶尖直接接觸眼睛，以免污染 Cravit Ophth Soln。
Action
Pharmacology: Levofloxacin, an optical isomer of ofloxacin (l-form), has 2 times more potent antibiotic activity than ofloxacin.
Mechanism of Action: The main mechanism of action of levofloxacin is to inhibit DNA gyrase activities of bacteria. Its effect is 2 times greater than that of ofloxacin. There was no difference between minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs), indicating its effect being bactericidal. Also bacteriolysis around MICs was shown in morphological observation. Microbiology: Antibacterial Activity: Levofloxacin exerts a broad-spectrum potent antibacterial activity against organisms causing ophthalmological infections, including gram-positive bacteria [Staphylococcus sp, Streptococcus sp, (including S. pneumoniae), Micrococcus sp, Enterococcus sp, Corynebacterium sp, etc], gram-negative bacteria [Pseudomonas sp, (including P. aeruginosa), Haemophilus sp, Moraxella (Branhamella) catarrhalis, Moraxella sp, Serratia sp, Klebsiella sp, Proteus sp, Acinetobacter sp, etc] and anaerobic bacteria (Propionibacterium acnes, etc).
The antibacterial activity of levofloxacin against standard strains for each bacteria and clinically isolated bacteria identified in patients with external ocular infections was about twice as potent as that of ofloxacin (in vitro).
Effects on Experimental Pseudomonas aeruginosa Keratitis in Rabbits: Levofloxacin ophthalmic solution was effective in preventing experimental P. aeruginosa keratitis in rabbits.
Indications/Uses
The following infections caused by levofloxacin-susceptible strains of Staphylococcus sp, Streptococcus sp, Streptococcus pneumoniae, Micrococcus sp, Enterococcus sp, Corynebacterium sp, Pseudomonas sp, P. aeruginosa, Haemophilus sp [H. influenzae, H. aegyptius, (Koch-Weeks bacillus)], Moraxella (Branhamella) catarrhalis, Moraxella sp (Morax-Axenfeld bacillus), Serratia sp, Klebsiella sp, Proteus sp, Acinetobacter sp, Enterobacter sp, Propionibacterium acnes: Blepharitis, hordeolum, dacryocystitis, conjunctivitis, tarsadenitis, keratitis, corneal ulcer and postoperative infections.
Dosage/Direction for Use
For ophthalmic use only.
Usually, instil 1 drop at a time, 3 times daily. The dosage may be adjusted according to the patient’s symptoms. Administration: At the time of administration, the patient should be instructed not to touch the tip of the bottle directly to the eye in order to avoid contamination of Cravit Ophth Soln.
