Ask the Doctor/Q&A

Q. I am on carbidopa/levodopa 25/100. What do the numbers 25 and 100 mean?

A. The numbers correspond to the formulation of the medication. In this case, it means you are taking a combination pill of carbidopa 25 mg and levodopa 100 mg. Without the carbidopa, the levodopa would be broken down in the body before it got a chance to make it into the brain. The carbidopa acts to inhibit the enzyme that breaks down levodopa.

There are various carbidopa/levodopa formulations on the market that differ in the dosage amounts of the two medications (e.g. 10/100, 25/100, 25/250) as well as the physical properties of the pill that may make the dose onset quicker or last longer (e.g. Sinemet, Sinemet CR, Parcopa, Rytary). Your doctor will prescribe a formulation based on your medication requirements.

Q. I was advised to take my carbidopa/levodopa at least 30 minutes after a meal. However, this caused a lot of nausea and stomach upset for me, so I now take the medication with meals which I find to work much better for me. Is this OK to do?

A. There is no issue with taking levodopa with meals except for possibly reduced absorption – usually only in the presence of dietary protein and even this is only in a subset of patients. If you find that the medication works well for you when you take it with food, then you can continue doing what you are doing. It is always wise to talk to your doctor about any issues you’re having with your medication and discuss any potential changes in the dosing or timing.