A new study has suggested that adding a low dose of flecainide (Tambocor) to modafinil (Provigil) helped relieved excessive daytime sleepiness (EDS) in a few patients with Parkinson’s disease.

Lead author Dr. Jean-Christophe Corvol of Sorbonne University, Paris, said, “This association may improve wakefulness and cognition probably by modifying the interaction between neuronal and glial networks in the brain.”

Flecainide is a drug used to prevent and treat abnormally fast heart rates. It is only recommended in patients with potentially dangerous arrhythmias.

Modafinil is a smart drug that is advised for the treatment of EDS caused by narcolepsy and obstructive sleep apnea. It is also a nootropic that boosts cognitive function.

The study findings were presented at a poster presentation at the Movement Disorders Society virtual congress.

During the presentation, Dr. Corvol said modafinil alone had previously shown inconsistent results in patients with Parkinson’s and EDS.

The combination contained modafinil 200 mg/day and a low dose of flecainide (2 mg or 18 mg) daily. Dr. Carol reported, “The efficacy analysis showed no carry-over effect,” between the periods.

The researchers found that a low dose (2 mg) flecainide worked better than a high dose (18 mg) when given along with modafinil.

Dr. Alberto Espay of the University of Cincinnati, Ohio, who was not part of the study, told Medscape Medical News “So that’s kind of unusual that there isn’t a dose-dependent effect. Given the modest effects, I don’t know if this will translate into clinical significance.”

He said it might be interesting to see if the researchers “see anything in the data they collected that could speak about predictors of response, as well as predictors of lack of response so that they can perhaps fine-tune the selection of patients most likely to benefit for the next study.”

Dr. Crovol said, “The safety analysis showed no treatment-related serious adverse events.”

However, most of the side effects occurred in the higher dosage periods, such as headache, nausea and nasopharyngitis, insomnia, confusion, nightmare, and dry mouth.

Dr. Espay said a study against modafinil alone would be possible, “and in reality, the most important question to answer is not whether you have something that includes modafinil that’s better than placebo, but something in principle definitely that works better than…modafinil alone.” Questioning the choice of placebo as a control, Dr. Espay suggested that for “a company that wants to get these out in the market, it’s easier to demonstrate efficacy against a placebo than it is to demonstrate efficacy against an already existing active medication.”