You can find out more about NPF's National Medical Director, Dr. Michael S. Okun, by also visiting the NPF Center of Excellence, University of Florida Center for Movement Disorders & Neurorestoration.

In this month’s What’s Hot in PD? column, I will review a few of the most important medication-related issues.

First, there can be negative effects from inactive drug ingredients, especially from the color dyes often used in pill manufacturing. There have been serious hypersensitivity reactions reported from common pill dyes. A patient recently reported on the NPF Ask the Doctor forum that he had swelling of the face, lips and mouth shortly after switching from a blue Sinemet CR 25/100 to a yellow generic formulation. We also know of patients who have reported rashes when making similar switches. It turns out that, though rare, the yellow dye commonly present in the generic form of Sinemet (carbidopa/levodopa) can  be responsible for these types of side effects.  Contact your doctor if you suspect you have a pill color allergy. Be aware that yellow dye allergies may occur more commonly in patients who are also allergic to aspirin.  The treatment for the allergy is simply to have your doctor change you to a blue pill formulation.  Some patients also benefit from avoiding yellow dyes in their diet.

Second, in 2010-2011 there was a national shortage of Sinemet.  This occurred as the brand was transitioned from Merck and Company, Inc. to Mylan Pharmaceuticals, Inc.  The transition resulted in a worrisome and short-term drug shortage.  When generic formulations became available, multiple complaints were reported to the NPF Helpline.  These complaints ranged from weaker efficacy of the generic, worsening of motor fluctuations, dyskinesia, allergy and skin rash. When switching to a generic form, patients should keep in mind that there may be as much as a 20% difference in treatment effect.  However, a generic may sometimes be desired, especially in PD patients who experience dyskinesia from tiny medication dosages (some people have referred to these cases as “brittle” PD). One should remember that FDA approval of a brand name drug requires demonstration of its pharmacokinetics, efficacy, safety and tolerability in both a healthy population and also in the PD population. In contrast, approval of a generic drug only requires demonstrating its bioequivalence in the blood, but not its clinical treatment effect in PD.

And a final and important issue that has surfaced recently has been the “eight Sinemet limit.”  Pharmacies and insurance companies have been citing the language in the original FDA approval of Sinemet, and denying prescription requests for PD patients requesting more than 8 tablets a day.  This issue was the subject of NPF’s November 2010 What’s Hot in PD? column, Calling for the FDA to Revise the Eight Sinemet a Day Rule. The advent of electronic medical records has been compounding this difficult issue for patients, as automatic limits are now being set by nationalized computer systems.  Once limits are in computer systems, they can be challenging for individual patients to change.  If your insurance carrier or pharmacy blocks filling of your Sinemet prescription purely based on number of daily pills, we suggest you contact your doctor, send an appeal letter and also contact the NPF Helpline at 1-800-4PD-INFO (1-800-473-4636), as we are here to assist you.  The Helpline will provide important information for your appeal, including the recent publication on this topic in the journal Movement Disorders.

Selected References
Go CL, Rosales RL, Schmidt P, Lyons KE, Pahwa R, Okun MS. Generic versus branded pharmacotherapy in Parkinson's disease: does it matter? A review. Parkinsonism Relat Disord. 2011 Jun;17(5):308-12. Epub 2011 Mar 1. Review.

Okun MS. Parkinson's disease patients cannot get their dopamine replacement: The 8-sinemet limit. Mov Disord. 2011 Dec 9. doi: 10.1002/mds.24038. [Epub ahead
of print].