Last updated Jan. 5, 2022, by Teresa Carvalho, MS

✅ Fact-checked by Ana de Barros, PhD

Rytary (formerly known as IPX066) consists of carbidopa and levodopa extended-release capsules for early, moderate, and advanced Parkinson’s disease treatment. An extended-release medicine is formulated so that it is released slowly over time.

The combination of carbidopa and levodopa is one of the most commonly used treatments for symptoms of Parkinson’s disease. Rytary, approved by the U.S. Food and Drug Administration in 2015, is a singular formulation of carbidopa and levodopa, which provides a longer and more stable mode of action compared to immediate-release combinations.

How Rytary works

Parkinson’s is characterized by the death of dopaminergic neurons, which are nerve cells that communicate with other neurons by releasing a signaling molecule (neurotransmitter) called dopamine.

As such, dopamine levels in the brain decrease and Parkinson’s patients gradually experience a lack of motor control, among other symptoms.

Dopamine cannot be directly administered into the brain as it cannot cross the blood-brain barrier, a semipermeable membrane that protects the brain and spinal cord from circulating toxins or pathogens.

Levodopa therapy increases dopamine levels in the brain. The agent can get into the brain, where it is broken down into dopamine by nerve cells to replenish the brain’s supply. Carbidopa decreases the body’s conversion of levodopa so that more levodopa can reach the brain.

Rytary capsules contain beads that release carbidopa and levodopa at different speeds as they are dissolved in the gastrointestinal tract. Their absorption occurs over a prolonged period of time.

Rytary in clinical trials

Rytary has been evaluated in different clinical trials. In the APEX-PD Phase 3 study (NCT00880620), which enrolled 381 patients with early Parkinson’s, participants received either one of three fixed doses of the therapy or a placebo for 30 weeks. Results showed that Rotary was well-tolerated and provided significant clinical benefits at the three dosages tested, compared to placebo. Patients treated with Rytary experienced an improvement in their motor skills and their ability to perform activities of daily living.

The ADVANCE-PD Phase 3 study (NCT00974974) enrolled 471 patients with advanced Parkinson’s disease who were experiencing motor fluctuations or “off” periods — periods of time when the medication wears off and is no longer effective. Participants were randomized to receive either Rytary or immediate-release carbidopa/levodopa, their mainstay treatment, for 22 weeks. The study found that treatment with Rytary led to greater reductions in “off” periods and dosing frequency compared with the other treatment.

The ASCEND-PD trial (NCT01130493) was a crossover study of Rytary and a combination treatment of carbidopa/levodopa and entacapone, an enzyme inhibitor of levodopa breakdown. Participants taking the combination therapy were switched to Rytary over a six-week period, then randomized to one of the two treatments for two weeks and then crossed over to the other treatment for an additional two weeks after a one-week washout with Rytary.

Results showed a reduction in “off ” periods with Rytary compared with the other treatment, as well as a reduced dosing frequency to improve motor symptoms.

Other information

Rytary capsules are to be taken by mouth with or without food.

For patients who have not previously taken Levodopa, the starting dose is 23.75 mg / 95 mg three times daily. The dosage may increase to 36.25 mg / 145 mg three times daily on the fourth day of treatment. The maximum recommended daily dose is 612.5 mg / 2,450 mg.

People with an eye condition called glaucoma should not take Rytary. Nonselective monoamine oxidase inhibitors — an antidepressant medication — should not be taken with Rytary capsules and within two weeks of each other to prevent an increase in blood pressure.

Some multivitamin supplements or medications with iron may decrease the absorption of Rytary capsules, as may some high-protein and high-fat foods.

Rytary capsules should not be stopped suddenly as this may lead to complications.

Common side effects associated with the use of Rytary are abnormal dreams, constipation, dizziness, drowsiness, dry mouth, headache, nausea, trouble sleeping, and vomiting.

Additional information can be found on therapy’s label.


Parkinson’s News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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