Thoughtfully Observing Adverse Effects of Drugs: Old-School Dr. Tom Perry Teaches How to Spot Tell-Tale Signs of Drug Harm

Dr. Tom Perry believes that listening and observing thoughtfully can help protect patients from avoidable adverse drug effects.  As a specialist in internal medicine and clinical pharmacology at UBC he often uses video recordings to demonstrate changes in functioning of patients after reducing or stopping problematic medications.

(Alan Cassels at the Therapeutics Initiative interviewed him and this article has been edited for space and clarity).

Alan: Tom why do you use videos to teach medical and pharmacy students about the adverse effects of drugs?

Dr. Tom Perry: There is a major problem in medical teaching, these days. We are very good at the bedside, in teaching physical exams but we almost never use the physical exam to target the adverse effects of drugs we prescribe. These were all well-known and well-taught when I was in medical school in the 1970’s where we didn’t have video or the internet and we learned by in-person lectures or at the bedside.

Tom mimics the slurring of words, “‘when a patient izz hard to unnerstan, maybaze becuss off a dry throat…’  She might sound like that, difficult to understand and slurred because she might be under the effects of an anticholinergic drug.”

“Or someone who is expressionless (he quickly mimics a stone-cold motionless face)–might be under the influence of a dopamine antagonist. We might assume they are depressed, but it might be the intravenous metoclopramide for migraine that is the culprit.” Jerking his arm backwards, he adds, “or someone with myoclonic jerks—the involuntary twitching of muscles– might be under the influence of a number of different drugs.”

“What I like to do is use videos to teach students to actually see these effects—the slurring voice, the expressionless face, or the myoclonic jerks. These are very poignant to them—that they’ll remember them the next time they have a patient is in front of them.  I learned very late in my career that I was missing out on important clinical signs.”

Alan: What sorts of drugs might lead to these signs, for example ones that elicit dry mouth?

Dr. Tom Perry: “Well anticholinergic drugs are the drugs that block muscarinic-cholinergic transmission. Most of us don’t recognize the breadth of the spectrum of effects that they might cause.  Difficulty emptying the bladder, difficulty swallowing because of a dry mouth, or enhanced dental decay—which happens over months or years. How many doctors think of these commonly-used drugs could be doing these things?

“As well, many drugs Parkinsonize people, including drugs we use for nausea such as metoclopramide or prochlorperazine. My generation of doctors were expected to know these signs, to memorize them, but today’s generation I’m not so sure.  Those kind of observation skills are critical to good quality medicine especially in a society where so many people are taking multiple drugs.”

Alan: It sounds like it’s not easy work.

Dr. Tom Perry: “No, it’s not. Teasing out the problematic drugs from a drug list, I can sometimes do this rapidly because I’ve trained myself to do this quickly. Sometimes it’ll take me a minimum of an hour to go through a list to see what drugs are likely beneficial or harmful.   It takes a long time to sort out someone’s drug list but it’s very satisfying and liberating for me to sort out the chronic toxicity due to prescription drugs. But very few people have the time to do this. The solution to me is not to give so many drugs to the patient—in other words, don’t put the patient in that pickle in the first place. It’s everyone’s job.”

Alan: Do you have a hit list of drugs in your mind that you think are prescribed unnecessarily and send up a red flag?

Dr. Tom Perry: “One of my bête-noires is a drug called gabapentin. It made the manufacturer three billion in the US alone in the first few years on the market but it is basically a useless drug. It is a sedative and may be useful for some people but in many randomized trials it has shown to have minimal effects on conditions such as painful neuropathy, or after shingles. Yet it is prescribed very widely.  Pregablin has succeeded it and has similar properties and is seldom useful. There is also the widespread use of antipsychotics for people who are not psychotic. The evidence of benefit is incredibly weak and the likelihood of harm is substantial.”

“Look, someone treated with an antipsychotic could easily end up with diabetes that could have been avoided, and possibly a cardiac death.  Or with antidepressants we don’t know if they contribute to people returning to school or work.  There is no experimental evidence that they work that well. Maybe one in ten of people with extreme depression might be helped.  In my lifetime, antidepressants went from being very seldom used to today where maybe in our current class of classmates it has become completely normal. They might be beneficial, they certainly cause adverse effects, but are they an overall good idea? “

Alan: How can students better learn about the adverse effects of drugs.?

Dr. Tom Perry: “Medical students are told not to use Wikipedia but I found it extremely helpful and it’s rigorously edited. I also use the drug product monographs—search by the brand or generic name and the adverse effects are easily searchable in the product monograph. For example I did it this morning searching the drug monograph for duloxetine and dry mouth. I found that up to 10% of people experience dry mouth and about 30% nausea.”

“I had this 90 year-old patient who was wondering why she was put on duloxetine. Within two days she was on the brink of death with profound delirium, impaired consciousness and a plasma sodium of 108. She spent six days in hospital as a consequence, which happened after only two doses of duloxetine. If a prescriber was wondering if she’s the only one who has experienced this, it was easy to look up with two words:  ‘duloxetine and hyponatremia.’  Thanks to the internet you can learn stuff in 30 seconds that would have taken me a couple days in the library in the 1970’s. It becomes practical to look up common adverse effects when you prescribe a drug.   There is no excuse not to do that. After a while it begins to stick.”

Alan:  Final question. What can you say about current medical education?

Dr. Tom Perry: “Sadly, the changes in medical curriculum have diluted pharmacology education. Young medical professionals know next to nothing about drugs compared to what they would have known in the past.  Graduates from other universities elsewhere –such as in the middle east or South Africa have much more traditional medical education. Yet all is not lost. One can learn these things oneself.   We have to realize a very simple reality:  What I do as a doctor is to prescribe drugs –and as a doctor I need to know about them.”



Dr. Perry’s lecture (using videos) is called “How well do you know the drugs you prescribe?” This is part of the half-day Therapeutics Initiative Virtual Conference:

Bringing Best Evidence to Clinicians on October 16, 0830 to 1230 Pacific  General registration is $125 (Can), students only $30. You will earn 3.75 Mainpro+ credits.  Learn more and register here.