Mary Lou's new doctor sent her for a DEXA scan that showed that she had osteoporosis, with a high risk of a bone fracture if she didn't get treatment. This result was no surprise, as she had had other similar results in the past. The doctor carefully explained her treatment options. Mary Lou had previously taken a standard drug for osteoporosis and ended up with severe side effects.

Reluctantly, she agreed to try a different drug. A month later, she started coughing after swallowing a sip of water the wrong way. She couldn't stop coughing. She coughed on and off for hours, despite using every cough treatment she had in her medicine cabinet. Of course, it was late on Friday - isn't it always a weekend when problems crop up?

By the time Mary Lou was able to see her doctor on Monday, she had a fever of 102 degrees, couldn't talk at all without coughing, and was short of breath. The treatments he prescribed made her worse. She coughed for hours during the night - coughing so hard that she was vomiting - and had more trouble than she was comfortable with just breathing. She went to an urgent care clinic as soon as it opened the next morning.

The doctor there pulled out the big guns, giving her a steroid injection and two other medicines. Within about 12 hours, she was no longer coughing much at all and her breathing had eased.

She slowly recovered, but it took eight weeks before she could reliably talk normally without starting to cough. A few weeks after that, she went on a bicycle ride with two old friends. After a few minutes, she started coughing and tasted blood in her mouth. She was used to riding 30 or 40 miles, but that day she had to turn back after just a mile or so. She thought, "Boy, I am really out of shape!" Every time she tried to ride after that - even very slowly by herself on flat roads - she started coughing within a couple minutes and had to stop. She had never before experienced coughing when she exercised.

Over the next three months, she experienced one new symptom after another. Half a dozen times, her left arm suddenly became very weak, as if someone had flipped a switch and turned off the electrical current. She had never felt anything like it. She also felt very dizzy at unexpected times, something that had never happened to her before. Her doctor dismissed both symptoms.

Next, she developed a swelling the size of a golf ball on the inner part of her upper arm. That symptom led to a flurry of tests to see if she had breast cancer. She didn't; her doctor said that she just had an enlarged lymph node - but couldn't explain why. He also told her that the swelling would never go away. The next month, she developed a swelling on her leg that her doctor could not explain and that also never went down. Throughout these months, she also woke up frequently to find her heart racing, her pulse about twice its normal resting value.

Mary Lou was so fed up with all these unexplained symptoms - and getting no exercise for five months by then, because she coughed so much whenever she tried - that she decided to stop taking the drug for osteoporosis, after explaining her thinking to her doctor. Coughing and dizziness were both listed as possible side effects. A few weeks later, she tried bicycling a difficult, hilly course for an hour and completed it without a single cough. She quickly worked her way up to longer rides. She also stopped being dizzy.

Two years later, she has had no more unusual symptoms.

Does her experience prove that the drug caused all of these problems? No, but the data suggest that it may have. Side effects don't always show up within minutes or hours of taking a new drug. Keeping records of drugs taken and symptoms experienced may help identify hidden connections and help inform your decision about whether to keep taking a drug or to work with your doctor to come up with an alternative.