Her practice on Chicago's south side includes a lot of patients who can't afford to go to a doctor. People like Pat Milner, who was diagnosed two years ago with transverse myelitis - a rare, crippling disease.
"It was very scary," Milner says. "But I guess I didn't go to the doctor right away like I should have, because working temporary, you don't have medical coverage."
For Dr. Fagen, the challenge is coming up with creative ways to treat patients without insurance.
"When it comes to seeing a specialist, I can go and ask a specialist that I send a lot of paying patients to, 'Can you see this patient and not charge anything?'" Fagen explains.
And while she says we may have the best medical care in the world, the doctor is troubled by a health system that fewer and fewer people are financially able to access.
She says that of the 43 million Americans who are uninsured, they're frequently "the people who get caught in the middle, who get up and go to work everyday."
Why are one out of every six people in the U.S. without health coverage?
More and more, companies have learned they can avoid paying for expensive medical benefits by using outside contractors and part-time employees. And it could get worse - it's estimated health-care costs will rise 11 percent this year, driving premiums even higher and fueling further cutbacks.
Dr. John Winder, a Toledo-based physician who also conducts clinical trials for pharmaceutical companies, has begun to notice the number of people signing up for experimental drugs. He says they're coming in just to get free treatment for their illness, even if the drugs are yet to be fully approved.
"That's very common. People come out of the woodwork that have not seen a physician in years," Winder says. "They see it as an opportunity to get treatment."
People like Roland and Linda Gladieux, an Ohio couple who operate a car-repair shop. The Gladieux's say they go without health insurance because of its high cost: $550 a month, with a $2,000 deductible.
Linda Gladiuex fears what could happen if her family faces a health problem. "We could lose everything," she says. "You hope and pray every day that you don't get sick."
But they have been sick, and they've been to see Dr. Winder. Roland has chronic bronchitis and Linda has severe heartburn and arthritis, conditions they're treating in drug trials.
And while the Gladieux's are willing participants, they know that even if a test drug helps improve their health, it won't be supplied after the study ends. It's a problem Dr. Fagen has to deal with as well.
Fagen says she tries to offer free samples to patients who can't afford to fill prescriptions. But "sometimes we'll have to change what medication we're using, even thouh the one we're using may work, if we don't have any free samples of that one available right now."
For now, Pat Milner hopes she can hang on until the system is changed to give her better access to care and medication, and Roland Gladieux hopes he never gets seriously ill.
"I made up my mind that if something really major happens, I'll just suffer through it, just end up dying," he says. "That's where we're at - between a rock and a hard spot."