Merck announces its decision to stop the manufacturing of Sinemet CR

July 17, 2019: Merck has informed the Food and Drug Administration (FDA) that it will discontinue the manufacturing of Sinemet CR (controlled release). It emphasized that its decision is not a safety issue, but rather a manufacturing one. Patients who currently have Merck Sinemet CR at home can continue to use it until their supply runs out and pharmacies who currently have Sinemet CR will continue to dispense it until their supply runs out.

According to Merck, the company provides less than 1% of the approved uses of Sinemet CR in the US. The rest of the source of this medication is from pharmaceutical companies that manufacture generic versions. The companies that currently manufacture the generic equivalent of Sinemet CR, or carbidopa/levodopa ER (extended release), are Mylan, Accord, and Sun Pharmaceuticals. The majority of patients currently prescribed Sinemet CR, have therefore been dispensed a generic equivalent and will not be affected by this announcement. Patients who are taking Merck’s Sinemet CR should consult with their neurologist about this announcement. Generics and brand medications are both tightly regulated by the FDA and only a small amount of variability is allowed between brand and generics and between different generics. Most patients can switch from brand to a generic version or between generic versions without noticing a difference. A small number of patients may be able to detect a difference in their response. If this is the case, a small change in dosage may be enough to allow a patient to tolerate the change in formulation. Discuss this and all other medication issues with your neurologist.

It should also be noted that RytaryTM, or Carbidopa and Levodopa Extended-Release Capsules, has a similar name to the medications under discussion, but is not affected by this announcement.
Merck has also informed the PD community that it is committed to continuing to manufacture brand name immediate release Sinemet. There have been supply shortages of immediate release Sinemet in recent months which Merck is working towards resolving. (Generic versions of carbidopa/levodopa have not been subject to this shortage). Merck currently has no updates on when the shortage will be resolved. Please see this letter from Merck for more information.

Please call APDA’s hotline at 1-800-223-2732 with any additional questions on this issue.