HOUSTON - No one doubts the importance of health insurance, without it serious illnesses can become financial catastrophes. But many doctors say they're seeing insurance companies taking a bigger role in deciding what medicine you're prescribed and even how long therapy can last for a life threatening illness.

"In 95 percent of the cases, the commercial insurance companies are doing what they set out to do. pay the bill," said Dr. Joseph Galati, who specializes in liver disease, liver transplants and liver cancer. "But it's that 5 percent of the time let's say that you get into these situations where they're in a sense over riding what you'd like to do."

Galati says he's seeing more and more instances in which insurance companies want to stop a patients' therapy. The insurance company bases it's decision on medical journals and not the advice of the patient's doctor.

"My sense is and my colleagues feel on these serious clinical decisions leave the decision to us," Galati said.

Could your insurance company make a decision about your health care and not even tell you about it?

"I was a well informed consumer and still got taken by surprise," Karl Ittman said.

Ittman's 10-year-old daughter Neve was diagnosed with epilepsy at three months old.

"For the first year of her life it was all about the seizures and controlling the seizures," Ittman said. "It took us almost a year to control them within a certain amount."

A name brand seizure medication cut Neve's seizures down to about 10 a day. But when Neve started averaging as many as 40 seizures a day, her father discovered his insurance company was substituting Neve's seizure medication with a generic brand.

"I really didn't think about them just making me do generic and not name brand," Ittman said.

Many insurance companies have the right to switch name brand prescription drugs with generic ones without the patients consent or knowledge.

"What really upset me is my doctor is an expert and knows in medical terms what's best for Neve and his word was not enough for them to change their policy and make an exception," Ittman said.

Ittman says his out of pocket expenses to get the name brand drug went up about 200 percent.

"It's like a power struggle and part of the power struggle is about money obviously," Ittman said.

"The day of just going to the doctor, getting a prescription and getting it filled at the corner drugstore in many cases that day is gone," Galati said.

Even your pharmacy can overrride your doctor's decision on what medicine is best for you.

"They're taking the decision making away from me" Dr. Joel Goffman said.

For years the American Medical Association has fought against theraputic substitution by pharmacists without doctor approval.

Insurance companies will tell you their involvement can save patients money and they are not in the business of telling doctors how to treat their patients.

"I've never seen a situation where I could say point blank to you right now that the insurance carrier stepped in between the doctor and the patient and said we're not going to do that."

Still some physicians say insurance companies are putting profit before a patient's health.

"It's unfortunate that all of this is being based on economics, not care" Goffman said.