The findings of a new study suggests side effects of Thorazine and similar psychotropic drugs may carry a high risk of causing involuntary muscle movements, known as tardive dyskensia, which may become permanent.
Ethiopian researchers warn that high doses of Thorazine and other chlorpromazine-based drugs are linked to a drug-induced tardive dyskinesia risk, according to a report published in the December issue of Dove Medical Press.
Tardive dyskinesia is a disorder that causes repetitive and involuntary movement, usually involving the lower face and limbs, and has been linked to the side effects of a number of different medications. Symptoms can include grimacing, chewing, smacking of lips, rapid eye movements and impaired finger movements. There is no known effective treatment for the disorder, and the abnormal movements can become permanent, persisting even after use of the drug has stopped.
In this latest study, researchers conducted a cross-sectional study involving 410 subjects in Ethiopia with mental illness at a psychiatric clinic in Jimma University Medical Center, assessing which ones had tardive dyskinesia. The study was conducted from April 1 to June 5 in 2019.
According to the findings, more than 15% of cases were drug-induced and researchers determined that taking more than 600 mg doses of Thorazine was a major contributor. Other factors increasing the risks included being female, being between the ages of 30 and 44, having a major depressive disorder diagnosis, and taking anticholinergic drugs.
Researchers determined those taking more than 600mg of Thorazine and similar chlorpromazine drugs were 1.89 times more likely to develop tardive dyskinesia than those taking doses under 200mg.
The researchers found jaw movement and upper extremity movement were the most prevalent symptoms of tardive dyskinesia. In addition, they found that female patients were 3.7 times more likely to develop the condition than males, and patients with a major depressive disorder were more than twice as likely to develop drug-induced tardive dyskinesia than other subjects.
“The prevalence of drug-induced tardive dyskinesia in this study was high,” the researchers concluded. “Prescribing medications less than 600mg equivalent dose of chlorpromazine, giving attention for female patients, patients having a diagnosis of major depressive disorder, and reducing giving anticholinergic medications will be important measures for clinicians to reduce the occurrence of tardive dyskinesia.”