29 Nov 2022 How well do you know your dopamine antagonists?
Dopamine receptor antagonists are a broad class of drugs characterized by their ability to interfere with the natural actions of the neurotransmitter dopamine, typically in brain, but also in the anterior pituitary where dopamine suppresses release of the hormone prolactin. A large variety of dopamine antagonists are prescribed for serious mental illnesses, to control nausea and vomiting, and often for unapproved (“off label”) indications such as sleep or for behaviour control in people living with dementia.
Dopamine antagonists helped to end the era of mass institutionalization of people with disabling psychosis, but they also have protean adverse effects that are not always well recognized. The huge expansion in the number of pharmaceuticals that doctors, pharmacists, nurse practitioners and nurses are expected to “know” may have weakened our knowledge and understanding of this class of drugs.
Therapeutics Letter 139, published online November 29, 2022, aims to expand BC clinicians’ appreciation and insight into the effects of dopamine antagonists, including the unscientific but very successful marketing of the terminology “atypical” or “second generation” antipsychotics.
Therapeutics Letter 139 is video-illustrated
The online version of Therapeutics Letter 139 is accompanied by video illustrations of so-called “extrapyramidal symptoms and signs” (EPS) that can cause major and sometimes permanent problems for the people affected. Patients provided informed consent for the UBC Therapeutics Initiative to share their images and stories. In these brief videos, they explain why it is so important for prescribers, pharmacists, and patients and their families to understand and recognize early the occurrence of EPS or other adverse effects that are common during long-term use.
We hope this issue of the Therapeutics Letter will be read widely, and encourage you to share the online URL with colleagues and students, or with friends who you think might be affected adversely by a dopamine antagonist.
Watch the videos in the TI YouTube channel:
- Video 1 of 7: Drug-induced Parkinsonism from quetiapine
- Video 2 of 7: Parkinsonism reversed by stopping quetiapine
- Video 3 of 7: Akathisia from metoclopramide
- Video 4 of 7: Acute dystonic reaction to prochlorperazine
- Video 5 of 7: Acute dyskinesia from low-dose quetiapine
- Video 6 of 7: Tardive dyskinesia, Parkinsonism and depression from long-term metoclopramide
- Video 7 of 7: Recovery from TD and depression induced by metoclopramide
Christine Martin
Posted at 19:05h, 30 NovemberThank you to all the TI members involved in putting together this very important, and very informative information for us consumers, regarding the consequences of prolonged and overuse of these types of medications. Once prescribed, they often are not monitored adequately, and the adverse effects are not well communicated, if at all.
As was the case with my Mom, the serious harms that can result are often not recognized or reported by the patient, or misunderstood. While I acknowledge that there are many good medications that save lives, some antidepressant, antianxiety and antipsychotic medications are ineffective, harmful, or overprescribed.
I would like to thank one of your team for helping my late mother, who suffered from tardive dyskinesia. What she experienced was much more impactful than can be described in the written words in your Letter (or elsewhere). Fortunately, even after years of treatment with trifluoperazine, my mother was able to slowly taper off the causative antipsychotic medication, over 11 months. Because of a diagnosis given to her in the mid-1950’s, doctors originally believed that she could never discontinue this (or an equivalent) medication. That was a time when mental illness was very poorly understood.
My mother’s tardive dyskinesia symptoms were not recognized, but interpreted instead as a worsening of the original diagnosis. So more medications were added. These just worsened her symptoms, that had now manifested into tremor and shuffling gait that were thought to be symptoms of Parkinson’s disease. She was also thought to have dementia, because of her deteriorating mental condition.
Fortunately one of the TI physicians was asked to evaluate her before she started any medications to treat Parkinson’s disease or dementia. Were it not for that intervention to deprescribe trifluoperazine, my Mom would have been misdiagnosed, and unknowingly given more inappropriate medications, just worsening her condition.
If caught early, and if appropriate information is made available, tardive dyskinesia can be prevented. There seems to be very little awareness in the community about this adverse effect of antipsychotic drugs.
Your organizations’s motto of “Better Prescribing, Better Health.” is exactly that, from my experience. I am forever grateful for the help my Mom received.
Christine Martin
North Vancouver, BC, CANADA
(Christine Martin advises that she has no conflict of interest)