Istradefylline (Nourianz)

Istradefylline (Nourianz) is a prescription medicine that is used in combination with levodopa and carbidopa to treat adults with Parkinson’s disease (PD) who are having “off” episodes. “Off” episodes are periods of time when the symptoms of PD, such as tremor, stiffness, and slowness of movement, become worse or return. Istradefylline is the only treatment for “off” episodes that works by blocking the activity of adenosine, a chemical that may interfere with the effects of levodopa.

How does istradefylline work?

Istradefylline belongs to a class of drugs called adenosine A2A receptor antagonists. Adenosine is a natural substance that is involved in many processes in the body, including brain function. In PD, there is too much adenosine activity in some parts of the brain, which may reduce the ability of levodopa to reach the nerve cells that control movement. Istradefylline blocks the adenosine receptors, allowing levodopa to work better and longer.

What are the benefits of istradefylline?

Istradefylline has been shown to reduce the duration and severity of “off” episodes in people with PD who are taking levodopa and carbidopa. In clinical trials, istradefylline reduced the daily “off” time by about one hour compared to placebo. Istradefylline also improved the quality of life and daily functioning of people with PD who experience “off” episodes.

What are the side effects of istradefylline?

The most common side effects of istradefylline are uncontrolled sudden movements (dyskinesia), dizziness, constipation, nausea, hallucinations, and problems sleeping (insomnia). These side effects are usually mild to moderate and may go away over time. However, some people may experience serious side effects, such as abnormal thinking and behavior, confusion, aggression, agitation, delirium, and unusual urges (such as gambling, binge eating, or increased sexual urges). If you notice any new or unusual symptoms or behaviors while taking istradefylline, talk to your doctor right away.

How should I take istradefylline?

Istradefylline comes in tablet form that you can take by mouth with a glass of water. You can take it with or without food. The usual dose is one tablet (20 mg) once a day. Your doctor may adjust your dose depending on your response and tolerance. Do not stop taking istradefylline without your doctor’s advice. Stopping suddenly may cause severe reactions.

Who can take istradefylline?

Istradefylline is approved for adults with PD who are taking levodopa and carbidopa and experiencing “off” episodes. It is not recommended for children or pregnant or breastfeeding women. Before you take istradefylline, tell your doctor if you have any medical conditions, especially liver problems or mental illness. Also tell your doctor if you smoke cigarettes or use any other medicines, supplements, or herbal products. Some of these may interact with istradefylline and affect how it works or cause side effects.

Where can I buy istradefylline?

Istradefylline is sold under the brand name Nourianz in the United States and Kyowa Kirin in Japan. It is available by prescription only from licensed pharmacies. The price of istradefylline may vary depending on your insurance coverage, pharmacy location, and dosage. The table below shows some examples of prices in different countries based on online sources.

Table 1: Prices of istradefylline (Nourianz) in different countries

Country	Price per tablet (20 mg)	Reference
United States	$9.50	GoodRx
Japan	¥1,000	Kyowa Kirin
Canada	$7.00	Canada Drugs Direct
United Kingdom	£5.00	Pharmacy2U
Australia	$10.00	Chemist Warehouse

Conclusion

Istradefylline (Nourianz) is a new treatment for people with PD who experience “off” episodes while taking levodopa and carbidopa. It works by blocking the adenosine receptors in the brain, which may improve the effects of levodopa. Istradefylline can reduce the “off” time and improve the quality of life of people with PD. However, it may also cause some side effects, such as uncontrolled movements, hallucinations, and unusual urges. Therefore, it is important to consult your doctor before taking istradefylline and follow the instructions carefully.