Nourianz (istradefylline) is a brand-name drug that’s prescribed for Parkinson’s disease in adults. Nourianz comes as an oral tablet that’s typically taken once per day. Its dosage can vary depending on how symptoms respond to treatment.

Nourianz is approved by the Food and Drug Administration (FDA) to treat “off” episodes in adults with Parkinson’s disease. It’s prescribed only for people who are also taking levodopa/carbidopa (Sinemet, others).

Nourianz belongs to a drug class called adenosine receptor blockers. Nourianz is not available in a generic version.

Keep reading for specific information about the dosage of Nourianz, including its strengths and how to use the medication. For a comprehensive look at Nourianz, see this article.

Note: This article describes typical dosages for Nourianz provided by the drug’s manufacturer. When taking Nourianz, always follow the dosage prescribed by your doctor.

Below is information about Nourianz’s form, strengths, and dosages.

Nourianz form

Nourianz comes as an oral tablet.

Nourianz strengths

Nourianz comes in two strengths: 20 milligrams (mg) and 40 mg.

Typical dosages

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs. In some cases, doctors may adjust your dosage from those shown below.

Dosage for Parkinson’s disease “off” episodes

Doctors may prescribe Nourianz to treat “off” episodes in adults with Parkinson’s disease. The drug is prescribed together with levodopa/carbidopa (Sinemet, others). It’s not approved for treating Parkinson’s on its own.

If your doctor prescribes Nourianz for your Parkinson’s disease, your starting dose will likely be 20 mg. Typically, you’ll take this once daily. If this dosage isn’t working for you, your doctor may recommend another dosage increase — up to 40 mg once per day to treat your Parkinson’s disease. This is the maximum dosage of Nourianz that’s recommended.

For more information about your specific dosage, talk with your doctor.

How to take Nourianz

Nourianz comes as an oral tablet that you swallow whole. The manufacturer hasn’t stated whether it’s OK to divide, crush, or chew the tablet, or place it in water. You may take your dose with or without food.

If you have trouble swallowing tablets, see this article for tips on how to take this form of medication. You can also talk with your doctor or pharmacist.

Long-term treatment

Nourianz is meant to be taken as a long-term treatment. If you and your doctor determine that Nourianz is safe and effective for you, you’ll likely use it long term.

Before you start taking Nourianz, your doctor will discuss your treatment plan with you.


Some pharmacies offer labels with large print, braille, or a code you scan with a smartphone to convert text to speech. If your local pharmacy doesn’t have these options, your doctor or pharmacist might be able to recommend a pharmacy that does.

If you’re having trouble opening medication bottles, ask your pharmacist about putting Nourianz in an easy-open container. They also may recommend tools that can make it easier to open bottles.

It’s important that you do not take more Nourianz than your doctor prescribes. For some medications, taking more than the recommended amount may lead to harmful effects or overdose.

Effects of an overdose

Overdose effects of Nourianz can include:

If you take more than the recommended amount of Nourianz

Call your doctor right away if you believe you’ve taken too much Nourianz. Another option is to call America’s Poison Centers at 800-222-1222 or use its online tool. If you have severe symptoms, immediately call 911 or your local emergency number, or go to the nearest emergency room.

Below are some frequently asked questions about Nourianz.

What is Nourianz’s mechanism of action? How does the drug work?

A drug’s mechanism of action describes how it works to treat a condition or cause an effect.

Istradefylline is Nourianz’s active ingredient (what makes a drug work). Istradefylline works by blocking certain receptors (a type of protein) in your body. Unusual activity by these receptors, along with low amounts of dopamine, contribute to problems with involuntary movements.

However, it’s not currently understood exactly how this works to treat “off” episodes in people with Parkinson’s disease. Some research suggests that blocking this receptor may help treat movement symptoms caused by Parkinson’s disease.

It’s thought that this action is enhanced if Nourianz is taken with a drug that increases levels of the brain chemical dopamine. Drugs that increase dopamine include levodopa/carbidopa (Sinemet, others). This is why Nourianz is only approved to treat Parkinson’s disease when taken together with levodopa/carbidopa.

Talk with your doctor or pharmacist if you’d like to know more about how Nourianz or other medications work to treat Parkinson’s disease.

Does Nourianz have dosage adjustments based on liver function?

Yes, Nourianz does have recommended dosage adjustments based on liver function.

If you have a moderate liver problem, the recommended maximum dosage is 20 mg taken once per day. And even at this dosage, your doctor may monitor you closely for side effects from taking Nourianz.

For severe liver problems, taking Nourianz isn’t recommended. Instead, talk with your doctor to learn more about other treatment options for your Parkinson’s symptoms.

Talk with your doctor to learn more about the severity of your liver problem and what Nourianz dose is safest for you.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.