There's two ways of looking at the regulatory process:

Black and white: a drug is never to be used until it is approved by the regulator to treat named illnesses.

Shades of grey: the regulatory process produces information, which added to personal data suggest that the drug should or should not be used by a particular person.

The article pointed to in post 1 states:

"Isradipine is a Food and Drug Administration-approved drug to treat high blood pressure. Researchers suspect that the drug may also be effective in treating Parkinson’s for a couple reasons. First, population scale studies have shown that people taking the drug for high blood pressure have a lower incidence of Parkinson’s disease. Additionally, isradipine is in a category of drugs called calcium channel blockers, meaning they inhibit certain cellular functions. Researchers speculate that overactive calcium channels may play a role in the death of the dopamine producing cells in the brain that is one of the hallmarks of Parkinson’s."

Those people who see things in shades of grey and are using other drugs to treat high blood pressure may wish to discuss with their doctors moving to isradipine. It can be argued both ways whether this is an off-label use.

Many PwP have low blood pressure. Does this preclude using isradipine? Or, can a second drug be added to raise BP enough to off-set the decrease caused by isradipine? This sounds perverse, and may, indeed, be perverse. It is contingent on your assessment of the risks of PD against those linked to high blood pressure.

John