Optimizing Dosing and Treatment Selection of Amantadine

At the 2024 American Academy of Neurology Annual Meeting, NeurologyLive^® sat down with Parkinson disease (PD) expert Daniel Kremens, MD, JD, to discuss some of the top data being presented at the meeting on novel approaches in development for the treatment of the movement disorder. Kremens discussed these various presentations, offering his perspective on the clinical landscape.

In this segment, NeurologyLive inquired about Kremens's takeaways for clinicians from a 3-formulation comparison of the various amantadine formulations (Symmetrel, Osmolex ER, and Gocovri) that was presented at this year's meeting; and how these data can inform the optimal timing of dosing for amantadine products based on concentration levels, and if this this something for clinicians to consider when deciding their approach.

Transcript below edited for clarity.

Daniel Kremens, MD, JD: What we learned from this presentation is that not all amantadine is the same. We've known this from clinical practice, but sometimes people think that IR (immediate relase) amantadine and ER (extended-release)/DR (delayed-release) and DR/ER amantadine are all the same. What this study did was look at a modeling of the pharmacokinetics of the drugs. What we saw was that, in fact, they are very different drugs, with ER/DR amantadine having the profile that reflected the greatest pharmacokinetics.

When we think about clinically which medicines we're going to use, we should understand the pharmacokinetics. That should inform how we prescribe when we think about how we're going to dose the amantadine products. We have to understand the pharmacokinetics, particularly when we think about amantadine DR/ER, which is a delayed-release extended-release product. This is a product that has to be dosed in the evening, where from the delayed release you get a slow rise in the plasma levels of the amantadine over the course of the evening. When the patient awakes in the morning, they have high levels of amantadine and these levels in the plasma then slowly decrease over the course of the day. That's really important to understand, and that's how we want to dose this, as opposed to the pharmacokinetics of IR amantadine where you get relatively fluctuating levels and you don't achieve the higher levels in the plasma of the amantadine.