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Good Question: How Do Pills Know Where To Target?

MINNEAPOLIS (WCCO) -- Americans spend more than $250 billion a year on over-the-counter and prescription medications. When we have an ache or pain, we often take an aspirin or ibuprofen pill. But how do medications know where to target?

"Pills are actually really dumb," said Allyson Schlichte, PharmD, a pharmacist at Fairview Health Services, adding "they have no idea" where they're targeting.

So your aspirin doesn't know if it's your head or your back or your ankle hurting.

When you take a pill, generally it stays intact in the stomach, through the small intestine, and into the liver, where it dissolves.

"All medicines that we take orally then go to the liver, then go into the bloodstream, where they exert their effect," said Schlichte.

She compared the body and medication to a lock and key system.

"The medicine is like the key, it searches all over the body until it finds the locks that it fits into," she said.

So when you take ibuprofen, it's working everywhere, reducing swelling throughout your body.

"Your body doesn't notice when there's a little extra pain killer where you don't feel pain," she said.

That is why so many medications have such a giant list of side effects.

"Absolutely, it's because that drug doesn't know where to go -- so it's working where it shouldn't," said Schlichte.

Sometimes those side effects become intended effects: like with Viagra. It was originally designed to be a blood pressure drug with a goal of opening up blood vessels. The side-effect was improving erectile function in men who had trouble.

The theory also explains why people taking chemotherapy medication find that the drugs attack more than just cancer cells.

"The chemotherapy looks for fast-growing rapidly diving cell, and that's why a lot of people lose their hair. Their hair is a fast-growing rapidly dividing cell," Schlichte said.

There is hope that someday medications can become more targeted, said Schlichte. "We're working really hard in the research to try to find out if we can do targeted gene therapy."

In the meantime, we're stuck with medications that work everywhere.

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