Although quite rare, this week’s newsletter discusses some of what is known about the various types of movement disorder that have been reported in association with the use of antidepressant medications that are regularly prescribed to treat depressive disorders and anxiety disorders along with some lower frequency psychiatric and non-psychiatric diagnostic indications.
The data reported in the reference article address an extensive patient pool across all ages. The data reported comes from reported adverse drug reactions to these medications accumulated over the past 50 years based on reports from practitioners. The patient base thus includes many patients who may also have been receiving other psychotropic medications and who may have had multiple other medical conditions.
The report findings indicate that movement disorder side effects potentially attributable to antidepressant medications are reported in just under 3% of total side effect reports in the exceptionally large database used collected over a very extended period of time.
Notwithstanding the study’s limitations, the findings do support other reports of individuals on antidepressant monotherapies who have developed movement disorder side effects and there is thus clear indication that, though rare, it is appropriate for prescribers to monitor patients receiving antidepressant medications for a variety of movement disorder side effects, including the following nine subtypes, in order of frequency: tremor, dystonia, parkinsonism, restless legs syndrome, tardive dyskinesia, akathisia, myoclonus bruxism and tics.
The analysis indicates that females were just over twice as likely as men to report movement disorder side effects and that increased age of the patient was also a significant factor leading to increased reporting. Although there was some variance across antidepressant drug classes (tricyclic antidepressant, serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors and monoamine oxidase inhibitors), all classes of antidepressants appear to carry some limited risk for causing movement disorder side effects.
Not to be lost in this discussion, of course, is that both the more frequently occurring non-movement disorder classified side effects such as digestive disorders, sexual dysfunction, and fatigue/sleepiness and the other lower frequency ones such as hyponatremia, hepatitis, hair loss, and bleeding require monitoring as part of medication oversight activities.
The bottom line for prescribers is to remain vigilant for unwanted complications of treatment with both antidepressants (and all other psychotropic medications) through observation of the patient and inquiry of them about any new symptoms arising during psychopharmacologic treatment.
REFERENCE: Antidepressants and movement disorders: a post marketing study in the world pharmacovigilance database; Revet, Montastruc, Roussin, et al in BMC Psychiatry; June 16, 2020