It's recommended that a patient begin medications when Parkinson's disease symptoms begin significantly interfering with everyday activities at work or at home. Your family member's doctor may prescribe levodopa from the start or, if symptoms are still minor, begin with a dopamine agonist, an MAO-B inhibitor, or both. All Parkinson's patients eventually require levodopa, and the response to treatment usually unfolds in two phases.

Levodopa can work wonders in the early years. If your family member has run-of-the-mill Parkinson's disease, you can expect a "honeymoon" period during which levodopa provides good to excellent relief of core motor symptoms. Side effects are few.

Typically, activities that gave a person trouble before treatment began -- say, writing a check, making dinner, or chopping wood -- again feel smooth and easy. How long this honeymoon goes on varies from patient to patient, but it may last anywhere from two to seven years.

Red flag: A failure to respond well to levodopa (or dopamine agonists) could be a sign that your family member doesn't have Parkinson's disease and instead has one of several look-alike disorders. If her motor function doesn't seem to have improved from taking the drug, talk to her doctor about whether she should see a movement disorder specialist.