Is Your Energy Bar Messing Up Your Meds?

Six surprising medication snafus, resulting in poor workouts, bad dreams, underdosing—and maybe even an early grave.

By Stacey Colino
Rx medication prescription meds pink bottle pills pharmacy picture
Photograph: Ann Cutting

THE FDA can regulate a pill’s ingredients and dosage, but no government agency can control the other side of the medication equation: you. The effectiveness and safety of many widely used drugs are influenced by your age, weight, health, body fat and, especially, your gender, says Marianne J. Legato, MD, a professor of clinical medicine and head of the Partnership for Gender-Specific Medicine at Columbia University. For instance, women metabolize several drugs, such as the steroid prednisolone, faster than men; for that reason, women may need to take higher doses of them than men do.

Women also experience more side effects than men when taking the same medications. The antianxiety medicine diazepam (better known by its brand name, Valium) impairs psycho-motor skills more in women than in men; anti-histamines are more likely to make women want to take a nap. And fertile women have higher odds of experiencing skin reactions, especially rashes, to various antiseizure medications. Add up all the effects, and it turns out that women have a 50 to 70 percent higher risk of developing an adverse reaction to a drug than men do, according to an estimate from the Society for Women’s Health Research (SWHR).

While it’s hard to pinpoint why the sexes differ in their reactions to specific drugs, some general mechanisms are known. Women have a more active version of CYP3A4 enzymes, which are crucial for the metabolism of drugs by the liver; that’s one reason women process and clear some drugs comparatively quickly, explains Legato. Alternatively, women’s higher percentage of body fat means that drugs stored in fat tissue may have a longer-lasting effect in women than in men.

The bottom line: Women need to be especially vigilant about taking drugs, whether over the counter or prescription. Here are the most important nuances that your doctor or pharmacist may not take the time to spell out—and that you may not notice on the information sheet that comes with the product.

If you do encounter unusual symptoms that you think are drug related, tell your health care provider right away. “Your doctor should know if these are normal side effects or something potentially worrisome,” says Jennifer Wider, MD, medical adviser to SWHR and coeditor of The Savvy Woman Patient. Always consult your physician before you change your medications.


Cardiac arrhythmia, aka irregular heartbeat, resulting from drugs is probably the most studied side effect in women. “Since females tend to have a longer QT interval—the time it takes for the heart to relax between beats—drugs that further lengthen the interval could lead some women to have fatal arrhythmias,” says Legato. Medications with this potential include some commonly used antibiotics (like erythromycin, clarithromycin and sparfloxacin), anti-fungal drugs (fluconazole and others in the azole class), antipsychotics (such as thioridazine and pimozide) and antidepressants (particularly the older tricyclics, now used more often for migraine, irritable bowel syndrome and chronic pain than for mood elevation). Ironically, several anti-arrhythmia medications (such as disopyramide and sotalol) can contribute to irregular heart rates. At particular risk for developing drug-induced arrhythmia are people with heart disease or an electrolyte imbalance due to abnormal levels of minerals in the body, according to a 2008 review by researchers at Brown University.

PROTECT YOURSELF Make sure your physician knows if you have a heart-rhythm abnormality or a family history of heart problems. If she prescribes a new medication for you, ask whether it has been associated with any rhythm disturbances. Also, inquire if there are other drugs you should avoid while using a particular medication, because sometimes a combination of drugs can prolong the QT interval, Legato advises. When taking a new med, be on the lookout for any cardiovascular symptoms, such as heart palpitations and an out-of-breath feeling.


The hormonal changes that occur around menstruation can affect how quickly your body processes drugs, Legato says. During the second half of your menstrual cycle, progesterone levels rise, possibly inhibiting the stomach’s absorption of medications. “You may need to tailor the dose of your medication to the phase of your cycle,” notes Legato. For example, the anticonvulsant Dilantin is metabolized more rapidly at the beginning of the menstrual cycle than at any other time.
In addition, right before or at the very beginning of your period, shifts in the levels of estrogen and progesterone as well as cyclical changes in your immune function can also cause flare-ups in symptoms of asthma, depression, diabetes, irritable bowel syndrome, migraine or seizure disorders, among other conditions. As a result, at certain times of the month, the dose of medication that’s normally used to treat these conditions may not control your symptoms or prevent flare-ups.

PROTECT YOURSELF If you have any of those chronic health conditions, track your symptoms throughout your menstrual cycle so you can tell your doctor about cyclical flare-ups and describe how well your medication manages them. “You may need a higher dose of medicine at certain times of the month,” Legato says. Or you may need to take an additional drug at certain points in your cycle. Another tactic: Talk to your doctor about the possibility of using a hormonal contraceptive that will even out your monthly internal chemistry and thus reduce your flare-up potential.


It’s well known that drugs can interact negatively with other medications or supplements, which is why the labels or package inserts caution against taking those products simultaneously. But in a little-recognized phenomenon, certain medications can also interact with nutrients such as calcium, iron and magnesium that are found in fortified foods, boosting the chances that the treatment will either fail or produce nonoptimal results. “For example, the added minerals in iron-fortified cereal and calcium-fortified orange juice can bind with certain drugs and inhibit their absorption by the body,” explains Bethanne Brown, PharmD, RPh, a clinical associate professor of pharmacy practice at the Winkle College of Pharmacy at the University of Cincinnati. The list of drugs that interact with these foods includes commonly used antibiotics such as tetracycline, doxycycline and ciprofloxacin, and the thyroid medication levothyroxine. Also, the effectiveness of antihistamines such as fexofenadine declines if you take one around the same time you eat an energy bar that’s fortified with magnesium.

PROTECT YOURSELF If a package insert warns you not to take the drug with sources of calcium (such as supplements, antacids or dairy foods) or iron (such as supplements), you’re on notice that there could be an interaction with a fortified food, Brown says. In that case, your best bet is to put some time between the drug and calcium-fortified orange juice, fortified cereal or nutrient-charged energy bars or drinks: Take the pill an hour before the food or beverage or three hours after, which will allow your body to clear out the calcium- or iron-related ingredients.


Has your mind been playing scary movies while you’re asleep? That could be due to certain drugs you’re taking: sedatives (for anxiety or insomnia), beta-blockers (for hypertension, anxiety or migraine prevention), dopamine agonists (for Parkinson’s or restless-leg syndrome) and amphetamines (for weight loss or attention deficit disorder). What’s the connection? Because these drugs can affect the brain chemicals norepinephrine, serotonin and dopamine, they can also trigger nightmares by disrupting REM sleep, the stage during which most dreams occur, speculates Dennis F. Thompson, PharmD, a professor of pharmacy practice at Southwestern Oklahoma State University in Weatherford.

PROTECT YOURSELF If you’re bothered by bad dreams that started with a new drug regimen, mention the situation to your doctor or pharmacist to see if there’s a likely link. If there is, ask your doctor to switch you to a different drug that will adequately treat your condition without disturbing your slumber.


If you use a nasal decongestant spray or pain reliever (OTC or prescription) for five or more days in a row, or an antacid almost daily for several weeks or months, you may experience a rebound—meaning that once you stop taking the drug, your symptoms come back even stronger. Take the case of antacids, which neutralize the hydrochloric acid that can cause heartburn. “After the medicine wears off, acid-production cells in the stomach respond by producing more acid, potentially leading to increased pain,” says Jack Fincham, PhD, RPh, a professor of pharmacy practice and administration at the University of Missouri–Kansas City. What’s more, you can build up a tolerance to nasal decongestants, painkillers and antacids. “The more often you take some of these medications, the more of them you need to take to get the same effect,” Fincham explains.

PROTECT YOURSELF Use the lowest possible dose for the shortest possible period of time when you’re taking drugs known to produce rebound effects, Fincham advises. To avoid strong symptoms appearing after you stop using analgesics, nasal decongestant sprays and antacids, “taper off the medication gradually rather than stopping cold turkey,” suggests Darrell Hulisz, PharmD, RPh, a clinical pharmacist and associate professor of family medicine at Case Western Reserve University School of Medicine in Cleveland. This gives the relevant drug receptors a chance to return to normal rather than remain hyperactive. And talk to your doctor about alternative medications. For instance, if you need continuous relief from heartburn, look into taking an H2 blocker or a proton pump inhibitor; these don’t produce rebound effects. Finally, if you want long-lasting relief from nasal congestion, check with your doctor about whether you’d benefit from a nasal steroid spray.


Certain medications can make your exercise life more complicated. Beta-blockers (used for hypertension, anxiety and migraine prevention) can cause lethargy and reduced coordination during a workout because they slow down your heart rate and blood pressure. “When you run, your heart rate normally goes up because the heart pumps faster to get more blood into the muscles,” explains Elsa-Grace Giardina, MD, a professor of medicine and director of the Center for Women’s Health at Columbia University Medical Center. “But beta-blockers stifle that effect, making it harder to get an aerobic workout.” In addition, diuretics (used to treat hypertension and PMS) and anti-cholinergic drugs (for bladder control) can lead to dehydration, fatigue and muscle cramps during exercise. “Plus, cholesterol-lowering statins can make you tired by interfering with your body’s synthesis of coenzyme Q10, which is involved in energy production,” says Ronald Hoffman, MD, medical director of the Hoffman Center, a New York City practice that specializes in integrative medicine.

PROTECT YOURSELF If you’re using a beta-blocker, forget about aiming for a target heart rate during your workout; there isn’t one, because your heart rate is being slowed by the drug, explains Danine Fruge, MD, associate medical director of the Pritikin Longevity Center in Miami. Instead, use the RPE (rating of perceived exertion) scale, which measures how hard you think your body is working on a scale from 6 (no exertion at all) to 20 (maximal exertion). If you’re healthy, aim for the 13-to-15 zone (“somewhat hard”); if you’re new to exercise or have health problems, try for the 10-to-12 zone (“moderate”). If you’re following a diuretic regimen, drink more fluids than usual before, during and after exercise to prevent dehydration. And if you’ve been prescribed a statin drug, ask your doctor if a coenzyme Q10 supplement could counteract the drug’s energy-sapping effects, Hoffman suggests.

If a medication seems to be taking a serious toll on your workouts, see whether your doctor can change the dose or the time of day you take it, or whether you can switch to another drug, Fincham advises. The life-prolonging benefits of exercise are too important to miss out on.

Are You Expecting Too Much from Your Drugs?
If you have diabetes or high blood pressure and you take the requisite medications, you may assume you’re preventing the harm often brought on by these conditions, such as damage to your arteries. Not exactly. “These medications slow down a disease and buy you time—but they don’t completely stop the process,” notes Danine Fruge, MD, of the PritikinLongevity Center in Miami. Damage may not build up as rapidly as it would if you weren’t on medication, but some continues to occur, so you’re still at risk for developing complications and heart disease, explains Robert O. Bonow, MD, past president of the American Heart Association.

If you’re prescribed medication for diabetes or hypertension, you can improve your health further by doing what you can to help your body repair itself. The Rx: Upgrade your diet so it includes more vegetables, fruits, whole grains, legumes and low-fat protein; do 30 minutes of moderate exercise (such as walking) every day and stay at a healthy weight. “If you take medications and also make healthy lifestyle changes, it’s likely your condition will cause less damage than it would if you just took drugs,” Bonow says.

Originally published in the September 2011 issue of More.

Next: Are Two Drugs Better Than One?

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First Published Mon, 2011-08-01 10:03

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