Pharmacists warn against mixing

Prescription medications can interact not only with each other but with herbal supplements, vitamins, over-the-counter drugs, even some foods. So patients need to tell their pharmacists and physicians everything they're taking. And learn to ask questions.

That avoids a host of potential problems, according to pharmacists Robb Dengg and Rich Cox, both of LDS Hospital. The two men will be featured on Saturday's Deseret Morning News/Intermountain Health Care Hotline from 10 a.m. to noon, where they'll take calls about drug interactions, dosing, proper use of medications (including those that don't require a prescription) and more.

"The most important thing is people need to be proactive when it comes to medications and not be afraid to ask questions. We're not living in a time where you just take what you're told," Dengg said. "You should never be afraid to ask, and there really are no stupid questions when it comes to drugs."

Not asking can lead to drug interactions ranging from merely pesky to actually life-threatening. And nearly every compound has some interaction.

For instance, commonly prescribed anticoagulants like warfarin (Coumadin) should never be taken with over-the-counter medications that have blood-thinning action like aspirin or Pepto-Bismol.

Cox said that warfarin is also a poor idea with certain herbal supplements. "Nearly all the herbal supplements that start with 'g' — ginseng, gingko, etc. — affect your blood. So if you're taking Coumadin you should stay away from them."

Some herbals affect blood pressure, as well.

Besides the risk of interaction, there's danger of taking too much. Cough and cold remedies, for instance, often contain some benadryl or sudafed mixture. So if someone takes that along with Tylenol PM, which contains benadryl, he could very well get too much.

Herbal supplements are a bit of a mystery to most people, and interactions are less well known. They can interact with prescriptions and with each other, ranging from increasing the heart rate to simply interfering with medication.

It's best to pick a pharmacy and stay with it, Cox said. Pharmacies have databases that track what medications a patient is taking. If a new prescription would be contraindicated with something that is already prescribed, the pharmacist will be alerted to it. Often, patients see multiple doctors who don't know all the medications that have been prescribed for someone. And it's hard to keep track of every possible drug conflict.