Change scores, blood pressure

COMMENTS (with up to 10 mg, intravenously) "There were no changes in blood pressure or self-rating scores."... 

As antihypertensive drugs are intended to lower blood pressure, their evaluation in clinical trials requires at least two measurements. One of these is an initial measurement, typically called a baseline measurement, and the other is a measurement some time later, such as at the end of the treatment phase (the end-of-treatment measurement). These two measurements allow us to calculate a change score that represents the change in blood pressure from the start to the end of the treatment phase. Change scores can be calculated in several ways. One of these, and the method that is used in all of the examples in this book, is simply to calculate the arithmetic difference between each individual s baseline measurement and his or her end-of-treatment measurement. 

The maximal change in systolic and diastolic blood pressure during the time period of stenosis as compared to the initial values before drug administration is determined. There is no standardized assessment score. As an example, a reduction of systolic blood pressure by 30 mm Hg and of diastolic blood pressure by 20 mm Hg is quoted as a strong reduction in blood pressure. 

Table 6.5 Systolic blood pressure (SBP) values and change scores ...

In one study, slow-release nifedipine 20 mg twice daily reduced the mean steady-state theophylline levels of 8 asthmatics by 30%, from 9.7 to 6.8 mg/L. Levels fell by 50%, 56%, and 64% in three of the patients, but no changes in the control of the asthma (as measured by peak flow determinations and symptom scores) were seen. However, many other studies have found no changes, or only small to modest changes, in the pharmacokinetics of theophylline (given as oral theophylline or as intravenous lysine theophylline or aminophylline") in healthy subjects " or asthmatic patients " given nifedipine. The control of the asthma was unchanged by nifedipine. " Yet another study found that the combined use of slow-release theophylline and nifedipine improved pulmonary function and blood pressure control. ... 

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