Side Effects Of Provigil On Adhd Patients

Attention deficit hyperactivity disorder, or ADHD, is a psychiatric disorder characterized by inattention, hyperactivity and impulsivity. It is normally treated with stimulants such as methylphenidate or amphetamines, but some patients are unresponsive to these stimulants or cannot tolerate their side effects. Modafinil, marketed as Provigil, is a drug used to increase daytime wakefulness in patients with sleep disorders such as narcolepsy. Provigil is used off-label to improve symptoms of ADHD.

Clinical Trials

A 2001 study at Marshall University School of Medicine, published in the "Journal of the American Academy of Child and Adolescent Psychiatry," found that at an average dose of 195mg per day over 4.6 weeks of Provigil improved doctor, teacher and parent ratings of ADHD symptoms in previously unmedicated children. ADHD symptoms are also assessed via standardized questionnaires, including the Conners Rating Scales; ADHD Rating Scale-IV, or ADHD-RS-IV; and Clinical Global Impression, or CGI.

Dopamine Transporter Mechanism

Provigil, as a stimulant, increases signaling of the neurotransmitter dopamine in the brain. Provigil, by binding to the dopamine transporter, prevents reuptake of dopamine in the synapse back into the brain cell. A 2001 article in "The Journal of Neuroscience" reports that a Stanford University School of Medicine study with mice genetically engineered to lack the dopamine transporter found that Provigil did not increase wakefulness in these mice. This highly suggests that the therapeutic effects of Provigil require the dopamine transporter.

Adrenergic Signaling Mechanism

Adrenergic receptors accept the neurotransmitter norepinephrine. Provigil also changes adrenergic signaling, as wakefulness is reduced in rodents treated with alpha-adrenergic receptor antagonists that block adrenergic signaling, according to the Provigil prescribing information. Other drugs that increase adrenergic signaling---including clonidine, guanfacine and propranolol---are used to treat ADHD.