Efficacy And Safety Of The Drug

Efficacy is the ability to produce an effect (e.g., lower blood pressure).

Efficacy can be accurately assessed only under ideal conditions (i.e., when proper criteria select patients and strictly adhere to the dosing schedule). Therefore, efficacy is measured under skillful supervision in a group of patients like to have a response to a drug, such as in a control clinical trial.

Strength differs from efficacy in considering how well a drug works in real-world use.

Often a drug that is effective in clinical trials could be stronger in actual use. For example, a drug may be highly effective in lowering blood pressure but low in strength because it causes so many adverse that patients stop taking it. Strength may also be less than efficacy if clinicians inadvertently prescribe the drug inappropriately. Therefore, effectiveness tends to be lower than efficacy.

Patient Oriented Results

Patient-oriented outcomes are those that affect the well-being of the patient. They comprise one or more of the following:

life extension

Improvement of function (e.g., prevention of disability)

Symptom relief

Surrogate Results

Surrogate or intermediate results involve factors that do not directly involve the well-being of patients.

It is often things such as physiologic parameters (e.g., blood pressure) or test results (e.g., glucose or cholesterol levels, tumor size on CT scan) that are thought to predict outcomes. Real patient oriented. For example, clinicians typically assume that low blood pressure will restrain the patient-oriented outcome of uncontrolled hypertension (e.g., death from a heart attack or stroke). However, a drug might lower blood pressure but not lower mortality because it has fatal adverse effects. Also, if the surrogate is simply a marker of disease (e.g., HbA1C) rather than a cause of the disease (e.g., high blood pressure), an intervention could reduce the marker in ways that do not affect the underlying disorder. Therefore, indirect outcomes are less desirable measures of efficacy than patient-oriented outcomes.

On the other hand, surrogate results may be much more feasible, e.g., e.g., when patient-oriented outcomes take a long time to appear (e.g., renal failure as a consequence of uncontrolled hypertension) or are rare. In such cases, clinical trials must be very large and run for long unless there is an alternate outcome. In contrast, surrogate outcomes are often continuous numerical (e.g., blood pressure, blood glucose). Unlike dichotomous outcomes, numerical variables can indicate an effect’s magnitude. Therefore,

However, surrogate outcomes should be proven to correlate with patient-oriented outcomes under ideal conditions. Many studies in which such a correlation seemed reasonable but was not present. For example, treating certain postmenopausal women with estrogen and progesterone resulted in a possible lipid profile. Still, it failed to achieve the postulated corresponding reduction in myocardial infarction or cardiac death. Similarly, lowering blood glucose to near normal concentrations in patients with diabetes in the intensive concern unit resulted in high mortality and morbidity (possibly through triggering hypoglycemic episodes) than lowering blood glucose at a slightly higher level. Some oral hypoglycemic drugs lower blood glucose, including HbA1C levels, but do not lower the risk of cardiac events. Some antihypertensive drugs lower blood pressure but do not lower the danger of stroke.