To err is human… Avoid these common medicine missteps

You may be overlooking some habits or beliefs that can keep you from getting the full benefit of your medicines or cause you to risk your health and safety. See if any of these common medicine missteps apply to you.

by Michael R. Cohen, R.Ph.

Published Jul. 10, 2014, 9:45 a.m. ET

When it comes to medicines, you may already know how essential it is to exactly follow the instructions of your healthcare provider or directions on over-the-counter (OTC) Drug Facts labels. But you may be overlooking some habits or beliefs that can keep you from getting the full benefit of your medicines or cause you to risk your health and safety. See if any of these common medicine missteps apply to you.

Misstep: Keeping medicines in your bathroom medicine cabinet. The irony of a "medicine cabinet" is that it is the worst place to keep pills because the heat and humidity from bathing can speed up deterioration and make medicines less effective. Medicines should be kept in a cool, dry, and secure area, up and out of reach of children.

Misstep: Basing a child's dose of an OTC medicine on the child's age, not weight. Children metabolize (break down and absorb) medicine differently based on their weight, not age. So, weight-based dosing is more accurate than age-based dosing. This is especially important for children who are overweight or underweight for their age. Your child may be in the upper percentiles for weight for his age and need more medicine than a child on the thinner side. Always ask your child's doctor or pharmacist about the proper dose of an OTC medicine if your child's weight is higher or lower than what's listed for the corresponding age category on the label. Your child's doctor will factor in your child's weight when prescribing medicines.

Misstep: Taking daily low-dose aspirin at the same time you take daily ibuprofen or naproxen. Low-dose aspirin (81 mg) can help protect the heart from clots because it reduces the clumping of platelets that can block an artery. This effect happens because aspirin "sticks" to an enzyme called cyclooxygenase. Ibuprofen and naproxen also stick to cyclooxygenase. If they get to the enzyme first, there is no room left for the aspirin to adhere. If you only take ibuprofen or naproxen occasionally, it does not cause a problem. But if you take them regularly, take your aspirin at least 30 minutes before or 8 hours after taking ibuprofen or naproxen.

Misstep: Taking your vitamins in the morning and then skipping breakfast. Vitamins are classified as either water-soluble (vitamins B and C) or fat-soluble (vitamins A, D, E, and K). Fat-soluble vitamins require dietary fat from a meal to be absorbed properly in the body. The dietary fat carries the fat-soluble vitamins through the intestine, into the bloodstream, and to the liver where they are both stored until needed. Without dietary fat, the vitamin would not reach the liver. So, if you take your multivitamin in the morning and tend to skip breakfast (or eat a totally non-fat breakfast), eat a few raw almonds as a chaser to ensure proper absorption.

Misstep: Taking St. John's wort when relying on birth-control pills or contraceptive implants to prevent pregnancy. St. John's wort is a common herbal mood-boosting medicine, but it can increase the breakdown of estrogen, the hormone found in many brands of contraceptives, which allows breakthrough bleeding to avoid unintended pregnancies. A report from the United Kingdom earlier this year described teo cases of unplanned pregnancy in late 2013 in women with implanted contraceptives containing etonogestrel (NuvaRing, Nexplanon) who also took St. John's wort. More than a dozen cases of unplanned pregnancy were reported in women who took both oral contraceptives and St. John's wort. Women using a hormonal contraceptive should not take St. John's wort or use a back-up form on birth control.