Talk with your healthcare provider prior to taking this drug if you have:
- Lung problems, such as asthma or chronic obstructive pulmonary disease (COPD)
- Kidney disease, such as kidney failure (renal failure)
- Liver disease, such as liver failure, cirrhosis, or hepatitis
- Malignant melanoma (a type of skin cancer) or any undiagnosed skin lesion
- Glaucoma (an eye condition)
- Any mental illness, including depression
- Heart problems of any kind
- A history of stomach or intestinal ulcers
- Any allergies, including allergies to foods, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant (see Lodosyn and Pregnancy)
- Breastfeeding (see Lodosyn and Breastfeeding).
Make sure to tell your healthcare provider about any other medications you are taking, including prescription and nonprescription medicines, vitamins, and herbal supplements.
(Click Precautions and Warnings With Carbidopa to learn more, including information on who should not take the drug.)
Dopamine deficiency (caused by a loss of dopamine-producing cells) in certain parts of the brain may be responsible for many of the symptoms of Parkinson's disease. Although it would make sense to give dopamine to help treat Parkinson's, this does not work, since dopamine cannot cross the blood-brain barrier to reach the brain. Levodopa is a precursor of dopamine, which means that the body can use levodopa to make dopamine. Unlike dopamine, levodopa crosses the blood-brain barrier.
Levodopa is almost always given in combination with carbidopa. Carbidopa delays the conversion of levodopa into dopamine until it reaches the brain, preventing or diminishing some of the side effects (especially nausea and vomiting) that often accompany levodopa therapy. Carbidopa also reduces the amount of levodopa needed for Parkinson's disease treatment. It is very important to understand that carbidopa has no effects on Parkinson's disease when used without levodopa.
Although most people take carbidopa as a carbidopa-levodopa combination product, rarely, some people need to take additional carbidopa. In such cases, carbidopa products can be helpful by increasing the carbidopa dose (without increasing the levodopa dose).