New and emerging considerations in Parkinson’s disease

Medications needed to address “off” episodes and debilitating symptoms

With roughly 1.5 million Americans diagnosed and 50,000 new incurable cases each year, Parkinson’s disease (PD) has become a prevalent condition in the United States. For some time, the cornerstone of treatment was with levodopa and carbidopa, but in our ever-aging population, medications are needed to address “off” episodes when drugs simply do not work and to treat debilitating symptoms of PD, such as tremor and gait difficulties.

“We need neuroprotective therapies that can be started much earlier than we currently start treatment,” said Jeannette Wick, MBA, RPh, FASCP, assistant director of pharmacy professional development at the University of Connecticut School of Pharmacy. “That is, right now we tend to treat the symptoms, when what we really need is to get to the root of things and have some treatments that are preventive.”

To offer patients gold standard care and prepare them for what to expect in the future, health care providers must become familiar with current and developing therapeutic options for PD. 

Recently, FDA extended its goal date for review of a levodopa inhalation powder (Inbrija—Acorda Therapeutics) from October 5, 2018, to January 5, 2019. If the drug makes it to market, this will be the second drug approved for Parkinson’s disease in more than 10 years, following safinamide’s (Xadago—Newron Pharmaceuticals) approval in 2017. Acorda Therapeutics claims that Inbrija has improved bioavailability by bypassing the digestive tract with inhaled delivery. 

Safinamide is an add-on treatment for patients who are taking levodopa/carbidopa (Rytary—Impax Laboratories) and can help reduce “off” episodes. Dopamine agonists such as ropinirole and pramipexole may also be considered, but note the two- to threefold increase in the odds of patients experiencing impulse control disorder. Pimavanserin (Nuplazid—Acadia Pharmaceuticals) helps manage nonmotor symptoms such as depression, dementia, psychoses, constipation, and sialorrhea, and it has robust effects in patients with cognitive impairments.

“One of the most significant changes in PD has been wider use of deep brain stimulation,” said Wick. “This is an area where pharmacists frequently can be helpful to patients and clinicians, as medications need to be adjusted in the perioperative period.” In contrast to other PD surgeries, deep brain stimulation (DBS) is reversible and causes minimal damage to brain tissue. DBS also allows adjustments to be made externally, based on symptoms.

The glucagon-like peptide-1 receptor agonist exenatide has shown trends toward less deterioration of motor function for patients in early studies. It might also provide some improvement in nonmotor symptoms and quality of life, but further research is needed. 

Likewise, more evidence on the use of cannabidiol (CBD) oil for PD symptoms would be helpful. While CBD oil is now used fairly often across the United States, much of the information gathered is anecdotal. 

For the full article, please visit www.pharmacytoday.org for the January 2019 issue of Pharmacy Today.