“Could this be a quetiapine effect?” So wrote the emergency room physician in the chart of a patient with Parkinson’s disease who was returning to the ER with frequent falls and pneumonia.
It was an excellent thought. Quetiapine, a medicine the patient was taking for impulsivity, is in a class of medications known as antipsychotics. They may be effective in patients with psychosis, but in Parkinson’s patients, they can prove problematic, as all of their side effects overlap with the symptoms of Parkinson’s itself, in effect magnifying the difficulties posed by Parkinson’s.
In this case, the patient was so rigid that sitting down in a chair was extremely difficult; and he had difficulty walking without “festinating,” the unusual gait shown by Parkinson’s patients that is a combination between standing on tiptoes and running and falling forward. He was also having difficulty swallowing food, which was leading him to aspirate, which in turn was leading to frequent readmission to the hospital with aspiration pneumonia.
These can also be signs, of course, of the inexorable progression of Parkinson’s disease, which can worsen even when it is well treated. What was unusual about this case–and the fact that caught the physician’s attention–was the rapidity of the patient’s decline. Classically, this sort of change is seen over years–not abruptly.
When the quetiapine was stopped and a medication for anxiety started in its stead, the walking difficulty, rigidity, difficulty managing his oral secretions and swallowing problem improved dramatically.
Gloria, another patient with Parkinson’s who had been recently started on quetiapine for panic disorder, suddenly experienced marked difficulty walking. She cried out in despair, “Will I be in a wheelchair soon?” When the culprit was identified and the medication stopped, she was able to walk without festinating and, happily, never became wheelchair bound.
The quetiapine story has another twist. Not only can it exacerbate the symptoms of Parkinson’s in close to 10% of patients–an effect that is more pronounced among patients with dementia–but according to Dr. Daniel Weintraub, a Parkinson’s expert at the University of Pennsylvania, it has not been shown to be effective for Parkinson’s psychosis–and yet it is frequently prescribed for this. In addition, it carries a black box warning: it increases the risk for death among patients with Parkinson’s, with a hazard ratio of more than two-fold. That risk is particularly pronounced in patients with Parkinson’s dementia, which both of these patients displayed.
“Iatrogenic” is a fancy word that physicians learn early in their medical training: it is derived from the Greek iatros–meaning physician and gen, meaning causing; it has come to mean “induced inadvertently by a physician or treatment.”
One of the possibilities physicians consider any time a patient presents with a new symptom is: could this symptom be caused by a medication the patient is taking? And if so, is the symptom a side effect of a medication, or a so-called drug-drug interaction, where one medication will react with another, often either increasing or decreasing its strength, or possibly causing an unfortunate interaction unique to that particular combination?
Every medication has known side effects: so the art of medicine is to be cognizant of those side effects and to prescribe only medications that are necessary, and to prescribe combinations of medications that are the least problematic for patients. In general, this also means prescribing as few medications as possible, since the number of potential interactions increases significantly with the number of medications taken.
It’s important to note that medication side effects can occur no matter how long a patient has successfully been taking a given medication. “Ken,” a patient I advocate for, presented to the emergency room with massive lip swelling. After determining that he had had no unusual dietary exposures or history of allergy, the emergency room doctor concluded that this was a rare side effect of lisinopril, a common blood pressure medication that Ken had been taking for 15 years. When the lisinopril was stopped, the lip swelling resolved.
Another patient, Julie, experienced a fairly common drug-drug interaction: she had been taking thyroid hormone for years, but suddenly felt it wasn’t working: she was experiencing excessive fatigue and feeling cold. She had recently started taking iron for mild anemia–and had been taking it at the same time as the thyroid medication. It turns out that iron binds strongly to thyroid hormone in the intestine, preventing its absorption. Julie’s thyroid hormone levels were found to be very low on blood tests, confirming the poor absorption.
When Julie’s primary care doctor recommended that she stop the iron supplements (it appeared that Julie’s anemia had resolved and so the iron was no longer necessary), Julie’s thyroid hormone levels normalized and her energy levels and other symptoms improved.
Other medications that can interfere with thyroid hormone absorption include calcium supplements, estrogen and medications for reflux like omeprazole as well as several foods; so it is important to take thyroid hormone at least half an hour before eating, and if one must take medications that interfere with thyroid hormone absorption, to take them far apart from the thyroid dose.
Therein lies the advantage of a full medication review, which is a prudent practice to carry out periodically with your primary care doctor. This means going over all of your medications, including any vitamins or other supplements that you buy over the counter as well as medications that you may be prescribed by a specialist or that you receive from a mail-order pharmacy; any medications, in short, that your PCP may not be aware of—to make sure that all of your medications are working for you–and not against each other. Also, you should ask your doctor or pharmacist about the most common side effects of each medication that you are on so you will know what to be on the lookout for should you experience one.
**All names and identifying details have been changed to protect client confidentiality. The suggestions given here are not intended as a substitute for the medical advice of your physician.
Photo credit: photo by freestocks.org, from Unsplash.com
