4.有關vancomycin用來治療methicillin-resistant Staphylococcus aureus（MRSA）感染之心內膜炎的敘述，下列何者正確？
(A)Vancomycin主要依據病人肝功能來調整劑量
(B)肥胖的病人應該用實際體重計算vancomycin給藥劑量，不受每日最高劑量2g之限制
(C)根據vancomycin谷濃度（trough concentration）調整劑量來確保療效
(D)Vancomycin谷濃度（trough concentration）須大於25 mg/L

回5F，資料來自UpToDate(重點已用螢光筆標示)：

Obese patients — There is no well-validated, universally accepted nomogram to guide the approach to vancomycin dosing in obese patients [10,23-25]. Our approach is as follows:

●Loading dose – The loading dose, if given, is based on actual body weight (up to a single maximum dose of 3 grams) in all patients who are overweight or obese. (See 'Loading dose' above.)

●Initial maintenance dose – For patients with body mass index ≥25 kg/m2 (calculator 2), we calculate an ideal body weight (calculator 3) and, depending on the result, proceed as follows:

•For patients with actual body weight ≤125 percent of ideal body weight, the initial maintenance dose is based on actual body weight, according to the nomogram (table 1).

•For patients with actual body weight is >125 percent of ideal body weight, our approach to determining the initial maintenance dose depends on whether the patient weighs up to 100 kg or more than 100 kg:

-For patients ≤100 kg, the initial maintenance dose is based on a calculated "dosing weight" according to the nomogram (table 1). (Note that the ideal body weight calculator (calculator 3) also calculates the "dosing weight"; refer to the right side of the calculator to locate the dosing weight result.)

-For patients >100 kg, we favor use of individualized dosing regimens based on pharmacokinetic calculations performed by clinical pharmacists. If such services are not available, it is reasonable to use an initial maintenance dose of approximately 30 to 45 mg/kg per day, based on actual body weight, in two or three divided doses for normal renal function [26]. The initial single maintenance dose should not exceed 2 g, irrespective of body weight. Further information on vancomycin dosing in the setting of obesity and renal impairment is included separately in the vancomycin drug information monograph.

Subsequent dose adjustments in obese patients are based on clinical response, kidney function, and serum trough concentration assessments as in nonobese patients [27,28]. (See 'Dose adjustments' above.)

就題目來說，討論的應該是initial maintenance dose的部分，該病人符合的條件已用黃色螢光筆標註，結論要使用實際體重來計算劑量，綠底部分回答你的問題：不要超過2g是initial single dose，不是daily dose。

(B)肥胖的病人應該用實際體重計算vancomycin給藥劑量，不受每日最高劑量2g之限制

簡單來說最佳解有問題

正確的是6F的說法

(B)肥胖的病人應該用實際體重計算vancomycin給藥劑量，受單一最高劑量2g之限制 

77.謝先生身高170 cm，體重100 kg，理想體重63 kg，預計30 mg/kg/day，每天分2次給，vancomycin每次劑 量多少最為適當？ 

(A)1,500 mg 
(B)1,000 mg 
(C)1,200 mg 
(D)945 mg 

108 年 - 108-1 專技調劑學與臨床藥學#74541

想請問為何這題不用考慮每天最多2g?

Vancomycin efficacy is linked to a correct dosage which should aim to reach an area under the curve (AUC)/MIC ratio of ≥400; serum trough levels of 15 to 20 mg/liter are considered a surrogate marker of an AUC/MIC ratio of ≥400 for a MIC of ≤1 mg/liter. For Staphylococcus aureus strains presenting with a MIC >1 mg/liter, an alternative agent should be considered.
Vancomycin doses must be adjusted according to body weight and the plasma trough levels of the drug.
Nephrotoxicity has been associated with target vancomycin trough levels above 15 mg/liter.
 

Álvarez R, López Cortés LE, Molina J, Cisneros JM, Pachón J. 2016. Optimizing the clinical use of vancomycin. Antimicrob Agents Chemother 60:2601–2609. doi:10.1128/AAC.03147-14.

• 15 to 20 mg/kg (actual body weight) IV every 8 to 12 hours [5][2]; target trough concentration 10 to 20 mg/L (7 to 14 mcmol/L; MIC 1 mg/L or less); infuse doses greater than 1 g over 1.5 to 2 hours (guideline dosing) [2]; duration of therapy: 7 to 14 days (complicated skin and soft tissue infection), 4 to 6 weeks (bacteremia), 6 weeks (endocarditis), 7 to 21 days (pneumonia), 8 weeks minimum (osteomyelitis), 3 to 4 weeks (septic arthritis) [5]
• Seriously ill, loading dose of 25 to 30 mg/kg (actual body weight) IV to achieve rapid trough concentration of 15 to 20 mg/L or 10 to 14 mcmol/L (guideline dosing) [5][2]
• 2 g/day IV divided every 6 to 12 hours administered over at least 60 minutes (manufacturer dosing) [10]

(D)尿道感染、糖尿病足、皮府軟組織感染:10~15mg/L

     MRSA、心內膜炎、腦膜炎、骨髓炎、HAP、VAP:15~20mcg/mL