Carbidopa-levodopa therapy is currently the most effective treatment for symptoms of Parkinson’s disease (PD), but it isn’t perfect. After years of carbidopa-levodopa therapy, often given as Sinemet® (carbidopa levodopa), most people begin to experience fluctuations in their symptom control. The fluctuations are known as “on” time (when the medication is working and symptoms of PD are controlled) and “off” time (when the medication has worn off, such as between doses, and symptoms are apparent). Another possible long-term side effect of carbidopa-levodopa therapy is dyskinesia, the uncontrollable, abnormal movements that cause the arms, legs, or other parts of the body to move on their own.
One of the complicating factors of PD is that it can affect the movement of the gastrointestinal system, particularly the speed at which the stomach empties its contents into the intestines. If you’re taking oral medications, like Sinemet, and the tablet is sitting in your stomach for a long time, the medication isn’t being absorbed into your body and could be causing “off” time.1
Duopa – A different way to deliver levodopa
Duopa™ (carbidopa/levodopa enteral suspension) is a combination of carbidopa and levodopa in a suspension form (gel) that is delivered directly into the intestines by a pump for up to 16 hours. Duopa bypasses the stomach and delivers a continuous infusion of carbidopa-levodopa into the duodenum of the intestines, which often reduces or eliminates the fluctuations for many patients.
With Duopa, a procedure is required to make a small hole (called a stoma) in the wall of the stomach to place a PEG-J tube for delivery of the carbidopa/levodopa suspension. PEG stands for percutaneous endoscopic gastrostomy, and the J stands for jejunal, the upper part of the small intestines. The PEG-J tube is connected to a cassette containing Duopa and a pump, which moves the medicine from the cassette through the tube.2
Once the PEG-J tube is in place, the patient can connect to a cassette of Duopa each morning and receive a continuous dose of carbidopa/levodopa for 16 hours. The tube is flushed at night, and other medications may be taken for PD symptoms at night.2
However, Duopa isn’t right for everyone. It’s important to weigh the benefits and risks and discuss your options with a neurologist, particularly a movement disorders specialist who is specially trained in understanding how different drugs can affect a PD patient.
Pros of Duopa
Provides a continuous infusion over 16 hours of carbidopa-levodopa therapy into the small intestine2
Reduces the fluctuations of carbidopa-levodopa levels in the bloodstream that may be experienced with oral medications2
Improves the daily “on” and “off” times compared to oral carbidopa-levodopa2
The degree of improvement in “off” time rivals that seen with deep brain stimulation (DBS), a surgical procedure in which a device is implanted in the patient to deliver electrical pulses to the brain to decrease motor symptoms3
Duopa reduces the amount of carbidopa-levodopa pills an individual needs to take, and can be a good option for those with trouble swallowing (dysphagia)
Cons of Duopa
The tube placement comes with potential complications, including infection or redness at the insertion point, pancreatitis, bleeding into the intestines, dislocation of the tube, or blockage in the tube1,2
The cassette of Duopa must be changed daily2
The pump that moves the medication from the cassette into the small intestines is worn outside the body, which can be annoying or challenging for some2
The tube insertion point has to be kept dry, which means the pump needs to be detached before swimming, bathing, or showering4
It may take time to determine the correct dose of Duopa for each individual to effectively control symptoms2
In addition to the potential side effects as seen with all carbidopa-levodopa therapies (like nausea, vomiting, or orthostatic hypotension (falling blood pressure that occurs upon standing), some patients taking Duopa experience episodes of suddenly falling asleep without prior warning of sleepiness. This can be dangerous if these sleeping episodes occur during daily activities, like driving1,2
There is a higher rate of depression with Duopa compared to oral carbidopa-levodopa therapy, and patients taking Duopa should be monitored for depression or suicidal thoughts1,2
The abnormal movements of dyskinesia can still occur with Duopa1,2
Greig, SL. Carbidopa/levodopa enteral suspension in advanced Parkinson’s disease: a guide to its use. Drugs Ther Perspect. Mar 2016;32:177-185. doi: 10.1007/s40267-016-0297-2.
Duopa product website, AbbVie Inc. Accessed online on 7/24/16 at https://www.duopa.com/.