Modafinil elicits sympathomedullary activation

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System Pharmacology
• Neuroscience

Background:

• Modafinil is a psychostimulant prescribed to promote wakefulness and reduce fatigue.
• The autonomic nervous system's role in modafinil's effects remains largely unexplored.
• Understanding modafinil's impact on cardiovascular regulation is crucial for patient safety.

Purpose of the Study:

• To investigate the effects of modafinil on the autonomic nervous system.
• To assess modafinil's influence on heart rate, blood pressure, and catecholamine levels.
• To evaluate modafinil's impact on sympathetic nerve activity during orthostatic stress.

Main Methods:

• A randomized, double-blind, placebo-controlled, cross-over study involving 12 healthy subjects.
• Administration of oral modafinil (400 mg) or placebo for 3 days each, under controlled dietary conditions.
• Measurements included resting cardiovascular parameters, plasma and urine catecholamines, and peroneal microneurographic sympathetic activity during orthostatic tilt.

Main Results:

• Modafinil significantly increased resting heart rate, systolic blood pressure, and diastolic blood pressure.
• A substantial increase in plasma and urine norepinephrine and urine epinephrine was observed with modafinil.
• Modafinil attenuated peroneal microneurographic sympathetic activity during orthostatic tilt, despite cardiovascular stimulation.

Conclusions:

• Modafinil significantly perturbs autonomic cardiovascular regulation, increasing heart rate and blood pressure.
• The observed autonomic changes suggest potential risks associated with modafinil use in patients with pre-existing cardiovascular conditions.
• Further research is warranted to fully elucidate the cardiovascular safety profile of modafinil.