Therapeutic Effect and Side Effects of Pharmacotherapy in Patients With Parkinson Disease and Myasthenia Gravis: A Systematic Review of Case Reports and Case Series Studies

Purpose The co-existence of Parkinson disease (PD) and myasthenia gravis (MG) in an individual should be exceptionally rare. The purpose of this study was to systematically review the current literature regarding the therapeutic effect and side effects of pharmacotherapy on patients with PD and MG. Methods Five bioscience and engineering databases (MEDLINE via PubMed, Cochrane Library, Scopus, EMBASE, and China National Knowledge Infrastructure) were searched from inception through February 21, 2022. Case reports and case series studies investigating pharmacotherapy in patients with PD and MG were included. Procedures were followed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The methodologic quality of included studies was evaluated by using the National Institutes of Health Quality Assessment Tool for Case Series Studies. Findings Sixteen case reports and 5 case series studies with 32 participants met the inclusion criteria. Eight studies were rated as good quality, 10 were fair quality, and 3 were poor quality. The side effects of pharmacotherapy for PD or MG led to another disease, indicating an imbalance between dopamine and acetylcholine within human bodies. Implications When treating a patient who has PD or MG, health providers should be cautious about the occurrence of another disease. Timely treatment must rely on monitoring new symptoms as soon as the pharmacotherapy for PD or MG is initiated. Physical therapy may be helpful in decreasing the side effects of pharmacotherapy in patients with PD and MG. A new treatment pattern of pharmacotherapy + physical therapy for patients with PD and MG warrants further research. International Prospective Register of Systematic Reviews identifier: CRD42022308066.