Did you know that aspirin can cause asthma in some people? Or that as many as 90 different medications may cause lupus erythematosus, a chronic autoimmune disease characterized by fatigue and joint pain?
The fact that prescription medications can cause side effects is well-known. The idea that they can cause disease is not. Yet the difference between a drug-induced disease and an adverse drug reaction isn’t as great – or as dramatic – as it might seem.
“Really, it’s a matter of semantics,” says B. Joseph Guglielmo, PharmD, Dean of Pharmacy at the University of California, San Francisco. “The bottom line is, if a drug creates a complication of a normal body function, that’s a disease.”
Every prescription and over-the-counter medication has the potential to cause harm, particularly if used incorrectly. However, there are certain medications which are more likely to cause harm. Some of these include:
- High-powered antibiotics, such as tobramycin and vancomycin. These medications can be life-saving in some cases. However, they are also known to cause hearing loss and kidney damage, and that damage may persist even after the medication is stopped. These potentially irreversible side effects are one reason healthcare providers rarely prescribe these drugs as a first-line treatment.
- Steroids, including prednisone and cortisol. These drugs, which are used to treat everything from asthma to organ rejection, “have a very large spectrum of side effects, and the longer you’re on them, the more likely you are to have them,” Guglielmo says. Potentially serious, long-lasting adverse effects include hypothyroidism, glaucoma, cataracts and diabetes. Healthcare providers try to decrease the risk of drug-induced disease related to steroids by only prescribing them if necessary – and at the lowest effective dose, for the shortest possible time. Steroid treatment is also tapered over time, rather than stopped abruptly.
- Anti-cancer drugs. Chemotherapy and immunotherapy medications can kill cancer, but in many people, they also cause lingering damage, including damage to the nerves of the hands and feet, heart disease and secondary cancers.
Factors That Increase the Risk of Drug-Induced Disease
Two patients of the same age, gender and weight, and in similar health, can take the same medication at the same dose for the same amount of time. One may develop a drug-induced disease, while the other only experiences positive effects.
At present, it’s next to impossible to predict with much accuracy who will develop a drug-induced disease. Increasingly, scientists are untangling the genetic differences that likely account for at least some of the variation in response to drugs. For instance, healthcare providers now know that people with a gene called HLA-B*1502 have an increased risk of developing Stevens-Johnson syndrome, a serious disorder characterized by blistering and peeling skin, if they take carbamazepine, an anti-seizure drug .
But the ability to pinpoint susceptibility is still the exception, not the norm. That said, healthcare providers know that these 3 variables increase the risk of developing drug-induced disease:
- Age. “Every year you get older, you are at a greater risk for side effects,” Guglielmo says. In part, that’s because the body’s functioning changes over time. Most medications are metabolized by the kidneys or liver, and in general, these organs don’t work as efficiently as we age.
- Overall health. A person with multiple chronic diseases – say, diabetes and heart disease – is more likely to develop a drug-induced disease. The risk increases with each additional diagnosis.
- Medication usage. “The more drugs you are on, the greater the likelihood of adverse events,” Guglielmo says. That’s partly because each drug has its own side effect profile, and because more medications also means an increased risk of drug interactions. But it’s also because medications alter bodily function. Chemotherapy, for instance, is therapeutic, but also tough on the body – which “sets people up to be at risk for other diseases,” Guglielmo says.
Treating Drug-Induced Disease
In most cases – but not all – stopping the drug or tweaking the dosage may reverse the negative effects of a drug-induced disease and return the body to its usual functioning. In others, additional medical treatment and monitoring may be necessary.
If you or a loved one develop any new or unusual symptoms while taking a medication, write them down and share that information with your healthcare team. In fact, Dave Walker, PharmD, a pharmacist in Oregon, says that all patients should be on high alert when beginning a new drug.
“Patients need to be super-conscious of how they are affected by a medication when they first start taking it,” Walker says. He advises patients to keep notes, so that both the patient and the healthcare team can note the timing and trends of symptoms. People who develop obvious and alarming symptoms – such as difficulty breathing – should call their healthcare provider and seek medical attention ASAP. Less dramatic symptoms should also be reported to your healthcare provider, either via a phone call or at a follow-up visit. You can also call your pharmacist.
“Pharmacists are probably the most accessible healthcare providers out there,” Walker says. They are also the most knowledgeable regarding medications and their side effects.
How to Protect Yourself
You can’t eliminate the risk of drug-induced disease, but you can take steps to decrease your risk. Ask your healthcare provider these 5 questions whenever a new medication is prescribed:
- Why are you prescribing this drug? “Every patient should be absolutely crystal clear on what they are actually taking,” Guglielmo says. Make sure you know the name of the medication and its expected effects.
- What are the primary cautions with this medication? Many drugs have known toxicities. This information will help you watch for adverse effects.
- Are there any tests that could predict my response to this drug? Such testing isn’t yet commonplace, but it’s worth asking about.
- How should I take this medication? With or without food? First thing in the morning, or late at night? For how long? By what route?
- How is this drug eliminated from the body? If your healthcare provider says, “by the kidneys,” (or liver) and you have kidney (or liver) disease, speak up.
“One of the key things is for patients to be conscious and aware of the medications they’re taking, and ask questions,” Walker says.