Sept. 4 (HealthDay News) -- Intuniv (guanfacine) has been approved by the U.S. Food and Drug Administration to treat Attention-Deficit/Hyperactivity Disorder (ADHD) in people aged 6 to 17, drug maker Shire Plc said Thursday.

The once-daily drug, to be available in 1-to-4 mg. strengths, is expected on pharmacy shelves in November, the company said in a news release. The way it works is unclear, but the drug is thought to directly engage receptors in the brain's prefrontal cortex, an area that has been linked to the disorder

Intuniv is not a controlled substance and "has no known potential for abuse or dependence," Shire said. It cited statistics from the U.S. Centers for Disease Control and Prevention (CDC) that some 4.4 million children in the United States have been diagnosed with ADHD.

In clinical testing, the most common adverse reactions to Intuniv included tiredness, abdominal pain, dizziness, a drop in blood pressure, dry mouth and constipation, the company said.