Levosulpiride

Glucose metabolism is reported to be regulated by the central nervous system, but it is unclear whether this regulation is altered in diabetes. We investigated whether regulation of glucose metabolism by central dopamine D₂ receptors is altered in type 1 and type 2 diabetic models. Intracerebroventricular injections of both the dopamine D₂ receptor agonist quinpirole and the antagonist l-sulpiride induced hyperglycemia in control mice, but not in streptozotocin (STZ)-induced diabetic mice, a type 1 diabetic model. Hyperglycemia induced by quinpirole or l-sulpiride was diminished following fasting and these drugs did not affect hyperglycemia in the pyruvate tolerance test. In addition, both quinpirole and l-sulpiride increased hepatic glucose-6-phosphatase (G6Pase) mRNA. In STZ-induced diabetic mice, dopamine and dopamine D₂ receptor mRNA in the hypothalamus, which regulates glucose homeostasis, were decreased. Hepatic glycogen and G6Pase mRNA were also decreased in STZ-induced diabetic mice. Neither quinpirole nor l-sulpiride increased hepatic G6Pase mRNA in STZ-induced diabetic mice. In diet-induced obesity mice, a type 2 diabetic model, both quinpirole and l-sulpiride induced hyperglycemia, and hypothalamic dopamine and dopamine D₂ receptor mRNA were not altered. These results indicate that (i) stimulation or blockade of dopamine D₂ receptors causes hyperglycemia by increasing hepatic glycogenolysis, and (ii) stimulation or blockade of dopamine D₂ receptors does not affect glucose levels in type 1 but does so in type 2 diabetic models. Moreover, hypothalamic dopaminergic function and hepatic glycogenolysis are decreased in the type 1 diabetic model, which reduces hyperglycemia induced by stimulation or blockade of dopamine D₂ receptors.

Drug-induced movement disorders (DIMDs) form an important subgroup of secondary movement disorders, which despite conferring a significant iatrogenic burden, tend to be under-recognized and inappropriately managed.

We aimed to look into phenomenology, predictors of reversibility, and its impact on the quality of life of DIMD patients.

We conducted the study in the Department of Neurology at a tertiary-care centre in India. The institutional ethics-committee approved the study. We assessed 55-consecutive DIMD patients at presentation to our movement disorder clinic. Subsequently, they followed up to evaluate improvement in severity-scales (UPDRS, UDRS, BARS, AIMS) and quality of life (EuroQol-5D-5L). Wilcoxan-signed-rank test compared the scales at presentation and follow-up. Binary-logistic-regrerssion revealed the independent predictors of reversibility.

Fourteen patients (25.45%) had acute-subacute DIMD and 41 (74.55%) had tardive DIMD. Tardive-DIMD occurred more commonly in the elderly (age 50.73±16.92 years, p<0.001). Drug-induced-Parkinsonism (DIP) was the most common MD, followed by tardivedyskinesia. Risperidone and levosulpiride were the commonest culprit drugs. Patients in both the groups showed a statistically significant response to drug-dose reduction /withdrawal based on follow-up assessment on clinical-rating-scales and quality of life scores (EQ-5D-5L). DIMD was reversible in 71.42% of acute-subacute DIMD and 24.40% of patients with chronic DIMD (p=0.001). Binary-logistic-regression analysis showed acute-subacute DIMDs and DIP as independent predictors of reversibility.

DIP is the commonest and often reversible drug-induced movement disorder. Levosulpiride is notorious for causing DIMD in the elderly, requiring strict pharmacovigilance.