Pharmaceutical companies often distribute news releases about new drugs in clinical trials. Usually, there is a reference to a phase ranging from 1 to 4. Ever wonder what Phase II or Phase III clinical trials actually mean? This is a synopsis of the different types of clinical trials provided by the National Institutes of Health.

Phase I:
Study involves a small group of healthy subjects; typically 20-80 people. The objective is to determine what is a safe dosage range and to identify the side effects. In particular the liver and kidneys are monitored for any damage.

Phase II:
Typically several hundred people are selected. This study may or may not include people who have the disease that the drug is to control. One-half of the group is given the medication, while the other half receive a placebo. The study is looking for data that shows the drugs effectiveness. (e.g. lowering cholesterol).

Phase III:
From several hundred to several thousand people are involved in this study. The FDA closely monitors this study and has been known to halt the study if they feel the test subjects are endangered. The new drug is compared to other treatment methods. Adverse effects are closely monitored.

Phase IV:
This drug has been approved by the Federal Drug Administration (FDA) and available through prescription or over-the-counter. Physicians are not required to report drug related side effects, but what reports are made are sent directly to the manufacturing pharmaceutical company. When a side effect report is made to the manufacturer they are ‘supposed’ to inform the FDA. All side effects for any drug are not expected to be known until the drug reaches the general population. Additional drug side effects are always anticipated for every new drug.