Pharmacokinetics of drug infusions

In clinical practice, drugs are given by continuous infusionto maintain a predictable pharmacodynamic action. In anaesthesia,the most common route is by continuous i.v. infusion, but theextradural, subarachnoid and subcutaneous routes are also regularlyused. The effective use of drug infusions requires an understandingof both the pharmacokinetic and pharmacodynamic characteristicsof the drug used. Pharmacokinetics describe how the plasma concentrationof a drug changes over time, with the assumption that plasmawill equilibrate with an effect compartment to produce pharmacodynamicactivity. This article will describe, rather than derive equationsto explain, the pharmacokinetics of i.v. infusions and a basicunderstanding of simple models of pharmacokinetics and the relationshipsbetween parameters is assumed.     

逆转肾癌细胞系GRC—1耐药的实验与机理研究

为探讨对ＧＲＣ１细胞系药物耐受的逆转，采用ＭＴＴ比色法测定了异博定、ＢＳＯ以及异博定联合ＢＳＯ在细胞系ＧＲＣ１对阿霉素耐药的逆转效果。结果两种逆转剂单独与阿霉素作用均可以提高阿霉素对ＧＲＣ１的杀伤作用，以两种逆转剂联合作用效果更好。流式荧光法显示异博定对ＧＲＣ１耐药的逆转是通过增加细胞内药物积累实现的。研究表明，逆转ＧＲＣ１的耐药可以通过其不同的耐药机制实现。     

阿托伐他汀临床用药常见问题及合理用药分析

目的：分析阿托伐他汀临床常见问题，为合理用药提供科学依据。方法通过对我院2008年1月～2012年12月期间出现的29例阿托伐他汀不良反应的患者临床资料进行分析，总结阿托伐他汀临床用药常见问题，并提出合理用药措施。结果60岁以上老年患者出现阿托伐他汀不良反应者较高，所占比例为69.0%；患者不良反应发生时间均为药物服用后30min～3个月之内。联合用药患者中服用2～4种药物的患者有21例，所占比例为72.4%。临床不良反应以骨骼、肌肉损害最为常见，所占比例为48.3%。结论阿托伐他汀临床实际用药过程中应加强对患者血液、皮肤、肝、胆等方面的观察与监测，避免患者出现不良反应问题。     

Advances in drug delivery: Improved bioavailability and drug effect

Alterations in drug delivery produce substantial changes in the bioavailability of anticholinergic agents. These bioavailability differences change the efficacy and tolerability of this drug class, which consistently enhances patient compliance and overall drug effect. In order for drug delivery to alter successfully the bioavailability of a specific agent, the metabolism of that agent and the effect of the degradatory pathway on drug-parent compound levels need to be established. This will enable researchers to design improved or altered delivery pathways to maximize the benefits of these agents. Intestinal metabolism is known to affect certain agents, specifically oxybutynin chloride. Therefore, delivery techniques have been designed that either substantially lower or totally bypass intestinal (presystemic) metabolism. These alternate paths include extended-release oral, cutaneous, intravesical, and intravaginal routes. In addition, improvements in drug delivery have also been found to influence positively efficacy and tolerability profiles associated with tolterodine tartrate, another anticholinergic agent. A long-acting oral formulation has been shown to increase drug efficacy while decreasing tolerability concerns and side effects such as xerostomia. These salubrious effects are, in part, due to the more stable serum-drug concentrations that are imparted by this long-acting formulation.     

Intrathecal drug spread

Editor—I read with interest the review by Hocking andWildsmith¹ on intrathecal drug spread. I feel they omitted tomention an important aspect of drug spread that could have abearing for all blocks. They quite rightly stated that vasoconstrictors added to intrathecallocal anaesthetic could prolong the duration of a block, althoughnot affect