Association between Antidiabtic Medications and Worsening of Parkinson’s Symptoms: A Case Report

Introduction: Parkinson's disease (PD) is one of the most prevalent neurologic disorders, leading to progressive disability; it is characterized by tremors, slow movements, stiffness in arms and legs, and balance impairment; PD symptoms can be slowed but not stopped by treatment such as a combination of Carbidopa/ Levodopa. Although it's widely used for PD, it risks dyskinesia, orthostatic hypotension, and dizziness. The prevalence of PD in Saudi Arabia has been estimated to be 27 per 100,000 populations, and the occurrence of PD in the U.S. is approximately 20 cases per 100,000 people per year.  Case presentation: A 61 years old male presented with worsening PD symptoms, especially dysarthria symptom; he had a history of diabetes with A1C of 8.5%, on metformin, insulin glargine, liraglutide, and linagliptin, with good adherence, and he had a history of Parkinson on levodopa/carbidopa. Even there are no known drug-drug interactions between antidiabetic medication and levodopa/ carbidopa, he reported that coadministration of antidiabetic medications with levodopa/carbidopa cause PD symptoms worsening, especially dysarthria worsening. This drug-drug interaction was noticed when the patient tried to stop all of his antidiabetic medication except insulin mixtard, when he noticed dysarthria symptoms improved. He is currently on insulin mixtard for diabetes with an A1C of 6.7%.  Conclusion: Unintentional drug-drug interaction poses a challenge to the healthcare provider, so this report highlights the importance of adverse drug-drug interaction of antidiabetic with levodopa/carbidopa, its presentation, and management.