I started symptoms of parkinsons. Loss of smell almost total now. Ridgity and loss of balence has gotten worse. Would isradipine help. Sinemet (carbidopa and levodopa) helped.?

Maybe, see below. Isradipine has had some small studies that suggest it might be helpful, but we really don't know. There are many other medicines out there that are fda approved that will help more. Sinemet as you mentioned is one. Other medicines include the Dopamine imposters such as mirapex, requip, and neupro (rotigotine). I would recommend one of these before trying isradipine, which may not do much symptomatically.
GOOD JOB. Isradipine is not on market in usa and has only been used in mice, but this ca channel blocker for hypertension looks very promising for Dopamine deficiency. Too much time to go before it is available. For you, definitely use some l-dopa prep, might add azilect, and even consider Neupro (rotigotine) patch. This business is complex and a movement disorder specialist in a medical school may serve you best.

Related Questions

Why is Sinemet (carbidopa and levodopa) CR is inferior to regular Sinement in terms of strength even though they carry the same mg in terms of dose for Parkinsons?

Time release. Time released or controlled release Sinemet (carbidopa and levodopa) is not inferior- the drug is just released more slowly into the system. Read more...
Different timing. CR is sustained release. Regular lasts only a few hours and tends to have more peaks and troughs. One can use both. Regular is given 3 to 4 times a day. Read more...