Get the Most From Your Prescription Medications

The prescription medicine you're taking may not be doing its job effectively, because of other things you're taking with it.

According to Marketplace Morning Report, studies suggest that about half of all prescriptions never get picked up, and of those that do, about 50 percent are not taken correctly or completely.

In addition, a 2002 survey found that an estimated 19 percent of Americans took at least one supplement like ginkgo balboa or Saint-John's-wort. Many people don't tell their doctors about natural remedies they are taking, believing these remedies will not harm them in any way.

All these factors can combine and lead to people inadvertently harming themselves.

In their book, "You: The Smart Patient," Drs. Mehmet Oz and Michael Roizen write that every year about 40,000 people die and 1.3 million get seriously hurt from medication mishaps, including taking the wrong dose, getting the wrong prescription, mixing the wrong pills, or sometimes all three.

The doctors provided some tips for people to make sure they take their prescriptions correctly and not mix them with natural remedies that can either negate the medications' effects or cause a bad reaction.

List all medicines, vitamins and herbs for your doctor.

Ask the pharmacist about the prescriptions you get and how they might interact with any supplements.

Don't mix antibiotics and calcium. The combination inhibits absorption and weakens the effect of both. Calcium magnesium is also present in antacids, so beware of the ingredients of what you are taking.

Don't mix antidepressants and Saint-John's-wort. Although Saint-John's-wort has been used as a natural antidepressant for centuries, mixing it with an antidepressant can cause nausea, anxiety or confusion.

Don't mix cholesterol-lowering drugs with vitamins C and E. The vitamins inhibit the effectiveness of statin drugs because they are antioxidants and could reverse the drugs' effects.

Stop taking blood-thinning agents like ginger, garlic, gingko or ginseng one week before surgery. If you need emergency surgery, the doctor needs to know whether you're taking these dietary herbs.

Don't mix grapefruit juice and medication. Grapefruit juice can interact with a number of medications and prevent their absorption into the body. This is especially important because approximately one-fifth of all Americans drink grapefruit juice for breakfast -- when many take their pills.