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Barbara Dehn, RN, MS, NP, FAANP, NCMP

Practicing Nurse Practitioner


San Francisco, CA

Barbara Dehn, RN, MS, NP, is a practicing nurse practitioner and a television health expert, who's known as Nurse Barb. She's passionate about health education, whether it's 1 on 1 with a patient, in a lecture hall at Stanford or with millions of people watching on television. Her warm and engaging personality puts everyone at ease as they learn more about health.

Nurse Barb is the award winning author of the Personal Guides to Health used by over 5 million women in the US, with titles ranging from fertility and pregnancy to menopause and breastfeeding. Active in Social Media, she contributes content to HealthyWomen, Huffington Post, NurseBarb, KevinMD and The Patch and amplifies her reach with an active and engaged Facebook following and 34,000 Twitter followers.

She is the author of The Hot Guide to a Cool Sexy Menopause, Nurse Barb's Guide to Breastfeeding and Nurse Barb's Guide to Pregnancy.

Barb earned a masters degree from UCSF and a BS from Boston College. She's certified by the North American Menopause Society and is a Fellow in the American Association of Nurse Practitioners. Over the last 2 years, she's been an active participant in Global Health Initiatives at FAME Hospital in Karatu, Tanzania. Barb lives in the San Francisco Bay area.

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5 Questions About Clinical Trials

5 Questions About Clinical Trials

If you've ever been curious about what clinical trials do and how or why you may participate, check out these answers from Nurse Barb Dehn.

Women's Health Policy

Maybe you've seen in the news incredible reports about how cancers are being cured by modified viruses or maybe you've heard about a lifesaving new drug and wondered how modern medicine uses clinical trials to bring new options to people.

Here are the top five questions I get asked about clinical trials.

Whatever your level of curiosity, here are some answers from to help clarify a few things.

1. What is a clinical trial?

In a nutshell, clinical trials are ways that we answer questions about drugs and other treatments. The following are simplified, but you get the idea.

• Does this new medication work the way we hoped it would when it was developed?

• What's the right dose?

• What are the common side effects?

• Will eating more or less of a certain food help with diabetes, heart disease or any number of conditions?

• What happens when we combine two or more medications?

2. What are the types of clinical studies?

There are two types of clinical studies: clinical trials and observational studies.

In a clinical trial, people who qualify by meeting certain inclusion criteria are placed into groups by an investigator who is running the trial. One group will receive the intervention that is being studied. This might come in the form of a medication or other new treatment or a change in behavior (like a change in diet). Because investigators are trying to figure out if the new treatment works, they must compare it to either an existing treatment, no treatment or a placebo, which is used as the control in the study.

In observational studies, investigators look at large numbers of people and try to find common threads to explain why they experienced certain things. One example is the Nurse's Health Study (I happen to be a subject and fill out their questionnaires regularly).

By tracking behaviors, medical conditions, diet, exercise and much more on more than 180,000 nurses for over 20 years, the Nurse's Health Study has found, among other things, that women who exercise for at least 30 minutes each day have a lowered risk of developing breast cancer.

Observational studies can look back at data, which is known as a retrospective study. Observational studies can also track people in real time, by looking at the variables or things that seem to be related to certain outcomes. For example, a hospital may be tracking infection rates and determine that installing handwashing stations outside of every room reduces infections.

3. What is a placebo?

These are substances that do not contain any active ingredient or therapeutic effect (think sugar pills).We use placebos as controls when testing new medications. Many medications studied are only slightly more effective than placebos. This could mean that the medications aren't working or that just the idea of taking a medication or other treatment helps people feel better. In every study I've ever read, even people on placebos have side effects! More evidence of the power of the mind to transform how we feel.

4. Are there different phases to a clinical trial?

This is a great question. Obviously, when a new medication is being developed, safety is the number one concern, followed by whether it works in healthy people and what is the best dose.

As more is learned from each phase of the trial, researchers can fine tune what kinds of effects they are looking for and design the trial to find out more about how the medication works, the side effects and what people are experiencing.

Often a medication or treatment that was designed for one condition will end up working for a different one. An example is finasteride (Proscar, Propecia), which was developed to treat prostate symptoms and was found in clinical trials to also work on helping men regrow their hair.

The phase of clinical trial tells you what type of study it is.

The Food and Drug Administration (FDA) created these categories to describe the types of trials available:

FDA definition

What it means

Phase 0

Exploratory study involving very limited human exposure to the drug, with no therapeutic or diagnostic goals (for example, screening studies, microdose studies)

Studies of new technologies that test for a disease in patients or studies where small amounts of new drug compounds are tested for safety. These trials are not meant to treat or diagnose health conditions; the investigators simply want to see if they are actually onto something with their new drug or technology.

Phase 1

Studies that are usually conducted with healthy volunteers and that emphasize safety. The goal is to find out what the drug's most frequent and serious adverse events are and, often, how the drug is metabolized and excreted.

Healthy people volunteer to try out an intervention (and are often compensated for their time). These investigations determine if the intervention is safe to give to patients, what side effects or other unwanted outcomes it may cause, and helps investigators better understand how the drug works within the human body.

Phase 2

Studies that gather preliminary data on effectiveness. For example, participants receiving the drug may be compared with similar participants receiving a different treatment, usually a placebo or a different drug. Safety continues to be evaluated, and short-term adverse events are studied.

Determines if the drug works in people who have a certain disease or condition. Here the intervention is compared against other interventions to see if it actually works to treat the disease or condition it is targeting.

Phase 3

Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs.

Once a drug or intervention has proven effective, investigators try to see which dose levels work best and if there are any other population factors (age, sex, ethnicity, etc.) or drugs that may contribute to the intervention's level of efficiency.

Phase 4

A study occurring after the FDA has approved a drug for marketing. These include post-market requirement and commitment studies that are required of or agreed to by the sponsor. These studies gather additional information about a drug's safety, efficacy or optimal use.

At this point the intervention has been approved by the FDA and is available to consumers. However, the investigators must continue to monitor outcomes to determine if there are any long-term side effects or consequences caused by the intervention.

5. How can I (or someone I know) participate in a clinical trial? is a service provided by the U.S. National Institutes of Health that allows you to search lists of current clinical trials that are open to enrollment. To participate in a trial, you must meet the trial's eligibility criteria. This can include things like age, disease stage and other factors that make you either eligible to join or mean that you're not a candidate for participation in that specific clinical trial.

If you or someone you care about is looking into clinical trials for a condition, go to and start searching. Many times the information can seem overwhelming, but there are contacts available to answer questions. You can also speak with your own health care provider to help you determine if you'd be considered for inclusion in a trial. They may even help you contact the study coordinators to demonstrate your interest.

This blog originally appeared on Nurse Barb's Daily Dose. Barb Dehn is a women's health nurse practitioner, award-winning author and nationally recognized health expert. She practices with Women Physicians in the Silicon Valley of California.

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