This study is for people with neurogenic orthostatic hypotension (nOH), a condition that causes dizziness or lightheadedness when standing up, often due to conditions like Parkinson's disease. The study will test a new drug called CST-3056 to see how well it helps these symptoms. Participants will stop certain medications a day or more before starting the study.

Participants will take CST-3056 once a day for five days. The best dose for each person will be found based on their blood pressure and how they handle the drug. After staying in-patient, participants will get a call from the study team to check on their health.

• The study lasts for about a week, with medicine taken for five days.
• Participants must be willing to stop certain current medications.
• Regular phone check-ups will follow after the in-patient stay.

People 18 to 85 years old with stable health, who speak English, and can follow study rules may join. Certain health conditions and medications could prevent participation. It's important to talk to the study team about the risks and if this study is a good fit.