The main differences between Gocovri capsules and Osmolex ER tablets center around their approved uses, dosage forms and strengths, and studies submitted for FDA approval.

Approval of Gocovri was based on placebo-controlled clinical studies in patients with Parkinson's disease with levodopa-induced dyskinesias, while the effectiveness of Osmolex ER was based upon bioavailability studies that compared Osmolex ER to immediate-release amantadine. Gocovri and Osmolex ER are not interchangeable with other amantadine immediate- or extended-release products.

What are Gocovri (amantadine extended-release) capsules?

• In August 2017, the FDA approved Gocovri (amantadine) extended-release capsules for treatment of dyskinesia (uncontrolled involuntary movements) in patients with Parkinson's disease (PD) receiving levodopa-based therapy, with or without dopaminergic medications.
• In Feb. 2021, Gocovri was also approved to be used in addition to levodopa / carbidopa treatment in patients with Parkinson’s disease experiencing “off” episodes (when symptoms are not controlled).
• Gocovri is a capsule taken by mouth once daily at bedtime. It's available in extended-release form in 68.5 mg and 137 mg strength. Taking the medicine at bedtime will give better coverage during the day when Parkinson symptoms may be most bothersome.
• It is manufactured by Adamas Pharmaceuticals.

What are Osmolex ER (amantadine extended-release) tablets?

• In February 2018, the FDA approved extended-release Osmolex ER tablets, a combination of extended-release and immediate-release amantadine for the treatment of Parkinson's disease and drug-induced extrapyramidal reactions in adults.
• The tablet consists of an immediate-release outer layer and an extended-release inner core. Osmolex ER is taken once-daily in the morning, and is available containing 129 mg, 193 mg, or 258 mg of amantadine.
• Osmolex ER is from Osmotica Pharmaceutical.

What is dyskinesia and "off-time"?

In Parkinson's disease, dyskinesias lead to involuntary movements during waking hours which can impact your normal, daily activities and impact your lifestyle. Dyskinesias are due to prolonged levodopa treatment. Dyskinesia may appear as fidgeting, writhing, wriggling, head bobbing or body swaying in people with PD.

"Off-time" is when Parkinson's symptoms return between medication doses. Off-time may start after longer periods of taking levodopa, but it does not happen in all patients. Off-time might involve painful muscle cramps, increasing tremors, and other common symptoms like slowness, stiffness, and trouble walking (freezing, shuffling).

How do the studies compare with Osmolex ER and Gocovri?

At this time, there are no studies directly comparing Gocovri and Osmolex ER in patients with Parkinson's disease and drug-induced dyskinesias.

Gocovri was the first Parkinson's disease medicine demonstrated in controlled clinical trials to reduce both dyskinesia and “off-time” in patients receiving levodopa.

In two studies, a statistically significant reduction in the Unified Dyskinesia Rating Scale was seen in patients compared to placebo: 37% vs. 12%, respectively, in study 1, and 46% vs. 16% in study 2, both at 12 weeks.

• In studies compared to a placebo (an inactive agent), patients taking Gocovri had over one hour less "off-time" per day.
• The most common side effects with Gocovri (>10% and greater than placebo) were hallucinations, dizziness, dry mouth, peripheral edema, constipation, falls and orthostatic hypotension.

The effectiveness of Osmolex ER is based upon bioavailability studies that compared Osmolex ER to immediate-release amantadine, not in controlled clinical studies in Parkinson's disease patients.

• The FDA approved Osmolex ER under the FDA's 505(b)(2) pathway using amantadine data from previous clinical trials.
• The most common side effects reported in ≥5% of patients at the recommended dosage of immediate-release amantadine were nausea, dizziness, lightheadedness, and insomnia (trouble sleeping).

This is not all the information you need to know about Osmolex ER and Gocovri for safe and effective use. Review the full product handouts, and discuss this information and any questions you have with your doctor or other health care provider.