The fact is that many such interactions are not especially serious. They emerge as somewhat higher or lower than expected blood levels of one drug when combined with another, or unusual or more severe than expected side effects with a particular combination. Therefore, you will regularly find doctors prescribing some newly released drug to patients taking other medications, without knowing whether anyone has studied the combination for adverse interactions. For that matter, you will find many doctors quite unaware of those interactions that have been firmly established; it would be quite a remarkable doctor who could remember and keep track of them all. I suspect no such doctor exists.
Do not conclude that no one needs to be concerned over drug-drug interactions. Certain very specific combinations present real and drastic hazards. For example, a few years ago a young woman died because, while taking an antidepressant of a type called a monoamine oxidase inhibitor, she was given an injection of a common analgesic for severe pain, Demerol. This took place in a hospital, according to the orders of a physician. This particular lethal interaction had been established many years before, with many published case reports for documentation.
However, such dread interactions are relatively few; it is hoped, or at least wishfully thought, that most doctors do retain an awareness of them.
As a final example, consider interactions with alcohol. Many, many prescription medications carry warnings against use with alcohol, often prominently labeled on the pill bottle. This is especially true for psychiatric medications, most of which have at least the potential for causing sedation. Warnings against combining them with alcohol stem from a commonsense concern over additive sedative effects.
Often, patients who drink to a modest extent have worried about this. Few who drink a lot would worry; unless they decided to just throw the medication away without using it, they would be compelled to continue drinking. A warning on a pill bottle will not cure alcoholism. When patients do worry enough to ask, I have explained, to their surprise and relief, that this warning does not mean that there exists a potential interaction such that, taking even a glass of wine while on this medication, would mean they might just drop dead!
If you are waiting for me to reach a single-sentence conclusion about all this, give up waiting. Neither I nor any other doctor will reassure you that you can take St. John’s Wort with other medications. This excess of caution stems not so much from concern for the safety of the patient as from concern for the (financial) safety of the doctor giving such unconventional advice.
Do you recall how I began this dry article by promising you a hair-raising story? Here it is.
Not so many years ago, I admitted to hospital an elderly man coming from a nursing home.
I noticed he seemed to be on quite a lot of medications. I counted them. There were 25, to be exact. In some cases, the medications being co-prescribed represented variants of the same agent. For example, the physician had prescribed this patient no less than four different benzodiazepines, sedative drugs which are prone to cause confusion and falls in the elderly.
My Chief asked me to write up this case for him. He passed it on the state Board of Medicine.
Months later, I learned that the physician responsible for this extraordinary “polypharmacy” had his license to practice suspended.
Such a situation did not really surprise me. Everyone knows that physicians supposedly taking care of patients at nursing homes visit them infrequently and briefly. When called by the nursing staff after hours, most such physicians have no intention of driving to the nursing home to examine the patient and figure out the problem and treatment, which could take hours. It is much, much easier to prescribe a new medication over the phone. Sedative medications are especially helpful for “quieting” patients and calming staff. If the nurse replies the patient is already getting a certain sedative, it is easy to think of a similar sedative to add, one with a different name.
Is it any wonder that “na?ve” consumers search for “Alternative[s to conventional] Medicine? Perhaps they are less na?ve than physicians would like them to be!
Tags: adverse interactions, antidepressants, drug-herb interactions
