What to know about guanfacine for the treatment of ADHD
Attention deficit and hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that typically develops in children but can also occur in adults.
According to the Centers for Disease Control and Prevention (CDC), in the United States, doctors had diagnosed about 6.1 million children with ADHD by 2016. The CDC also report that 62% of these children were taking medications to treat their symptoms that year.
Doctors typically prescribe stimulant medications, such as methylphenidate (Ritalin), for people with ADHD. However, they may recommend trying a nonstimulant drug if other medications are unsuccessful or cause unwanted side effects.
In this article, we discuss the use and effectiveness of guanfacine for the treatment of ADHD. We also cover dosage and side effects, as well as risks and considerations.
What is guanfacine?
Guanfacine is an approved medication for children and adolescents with ADHD.
Guanfacine works by relaxing the blood vessels in the body, which improves blood flow and lowers a person's heart rate and blood pressure.
Guanfacine also comes in the form of extended-release tablets under the brand name Intuniv, which the Food and Drug Administration (FDA) have approved for the treatment of ADHD in children and adolescents aged 6–17 years old.
Doctors may prescribe Intuniv by itself or in combination with other stimulant medications.
How does it work?
In addition to lowering blood pressure, guanfacine affects the part of the brain that controls impulsivity and attention span. However, guanfacine acts on the brain less directly than stimulant medications, which means that it does not work as quickly and that it may take a few weeks before people experience the full benefits of this treatment.
It is important to continue taking the medication as the doctor directs, even if the symptoms start to improve.
Is it effective?
Guanfacine appears to be most effective in children up to 12 years old.
According to a 2011 drug review, although guanfacine has approval for the short-term treatment of ADHD in children between 6 and 17 years of age, it appears to be most effective in those up to the age of 12 years.
Clinical trials have found that children who took 1–4 milligrams (mg) of guanfacine had an average score decrease on the ADHD Rating Scale-IV of 17–21 points, compared with a reduction of 9–12 points in those who took a placebo.
However, these results were only statistically significant in children who were 6–12 years old.
The ADHD Rating Scale-IV measures ADHD symptoms and behaviors, such as hyperactivity, impulsivity, and attention difficulties. A lower score indicates less severe symptoms.
The FDA have only approved Intuniv for the treatment of ADHD. Intuniv is available as 1-mg, 2-mg, 3-mg, and 4-mg extended-release tablets.
The appropriate dosage of Intuniv depends on the child's age, weight, symptoms, response to the medication, and tolerance of side effects.
When prescribing Intuniv, the doctor will typically begin with the lowest dosage and then gradually increase this until the child's symptoms are under control.
The manufacturers recommend starting at a dosage of 1 mg per day and increasing this incrementally by no more than 1 mg per week. The maximum recommended dosage is 4 mg per day.
As Intuniv is an extended-release tablet, it is important never to crush or chew the pill. The child should swallow the tablet whole with a glass of water.
It is also important to take the pill at the same time every day, such as in the morning or evening, even on weekends and holidays. Missing doses may cause unpleasant side effects.
If a child misses two or more doses, the doctor may suggest restarting at the original 1 mg per day dosage and gradually adjusting this back up to their regular dosage.
Stopping the medication abruptly can also cause uncomfortable side effects. The manufacturers recommend slowly reducing the dosage by 1 mg every 3 to 7 days.
Like all medications, guanfacine can cause side effects. Possible side effects include:
- low blood pressure
- abdominal pain
- decreased appetite
- dry mouth
It is important to discuss any unpleasant or concerning side effects with a doctor, who may recommend lowering the dosage or switching to an alternative treatment.
Risks and considerations
Guanfacine may interact with other medications.
Guanfacine may not be suitable for children with liver or kidney problems or those with a history of cardiovascular issues, such as low blood pressure or heart disease.
Doctors may regularly monitor the blood pressure and pulse of some children taking guanfacine to make sure that everything is normal.
Guanfacine can interact with some other medications, including:
- ketoconazole (Nizoral)
- clonidine (Catapres)
- rifampin (Rifadin)
- carbamazepine (Tegretol)
- phenytoin (Dilantin)
- valproic acid (Depakote)
To minimize the risk of drug interactions with guanfacine, it is essential to inform the doctor of any medications or supplements that the child is currently taking.
Guanfacine is a nonstimulant drug option for the treatment of children with ADHD. A doctor may prescribe guanfacine if stimulant medications have been unsuccessful or have been causing harmful or unpleasant side effects.
To improve effectiveness and reduce the risk of side effects, it is vital that children take guanfacine as the doctor directs. Parents and caregivers should discuss any side effects or concerns with the child's doctor.