Yesterday, an industry-sponsored session for clinicians and scientists was held prior to the official start of 2nd World Parkinson Congress. Largely a review of current medical management of PD, the session included one tidbit that I found particularly interesting - a comment made by Mark Stacy, M.D.
He said that orthostatic hypotension, that is low blood pressure upon standing, is the most common, unrecognized symptom of PD.
Up to 40 percent of people with PD experience orthostatic hypotension. Drugs that are currently approved to treat hypotension, like midodrine, work, but may work too well. The problem for people with Parkinson's is that their blood pressure is generally normal upon lying down or sitting, and problematic only when standing. But midodrine is not “smart” enough to figure this out. So while the drug fixes the problem of low blood pressure when a person is standing up, it also acts when a person is not standing, often causing the problem of hypertension, i.e., high blood pressure.
A solution may be in the works in the form of a drug called droxipoda, approved in Japan and under clinical development in the US by Chelsea Therapeutics (one of the industry sponsors of the session). Much like levodopa, or L-DOPA, a dopamine precursor given to replace dopamine, droxidopa or L-DOPS, is a precursor to the neurotransmitter norepinephrine and is given as its replacement. Preliminary evidence from clinical trials, presented by Phillip Low, M.D. from the Mayo Clinic in Rochester, MN, seems to indicate that droxidopa may benefit orthostatic hypotension in PD without causing hypertension when a person is not standing.
It will be interesting to follow the fate of this drug as it is tested. Do you agree orthostatic hypotension is a problem? Are you waiting for better treatment for it? Let us know in the comment section below.