What Is Guanfacine?

Guanfacine is a non-stimulant medication that is FDA-approved to treat ADHD in children and teens. It can also be used off label to treat tic disorders and symptoms of autism.

Guanfacine is not as powerful in reducing ADHD symptoms as stimulant medications, but it’s especially helpful for children who are hyperactive and impulsive — who can’t sit still in class, blurt out answers, interrupt, melt down easily, or have trouble shifting gears. 

“I always describe guanfacine as a behavioral medication,” says Paul Mitrani, MD, PhD, a child and adolescent psychiatrist at the Child Mind Institute. It can help kids who struggle to regulate their impulses and emotions take time to pause before acting.

Guanfacine is a kind of medication called an alpha-2A adrenergic receptor agonist. Alpha-2 agonists — including guanfacine and clonidine, among others — were originally developed to treat adults with hypertension, or high blood pressure. But guanfacine may be best known as a treatment for ADHD.

Guanfacine (under the brand name Intuniv) was officially approved to treat ADHD in children in 2009 but has been used for this purpose since the 1990s.

The alpha-2A receptors that guanfacine targets are found in various regions of the brain and nervous system, but heavily concentrated in the prefrontal cortex, the part of the brain that helps regulate attention, emotion, impulsivity, and behavior.

Researchers don’t fully understand how guanfacine works, but it is thought to act by enhancing the functioning capabilities of those alpha-2A receptors in the prefrontal cortex, improving a person’s ability to focus “above the noise” of the environment.

Guanfacine also has a calming effect by acting on alpha-2A receptors in the sympathetic nervous system, reducing sympathetic nerve impulses. This calming effect is especially helpful for hyperactivity and impulsivity. The sympathetic nervous system also regulates blood pressure, thus the drug’s original use.

Guanfacine can be used to treat ADHD on its own, but it is commonly used in addition to a stimulant.

The first-line medication treatment for ADHD, for both children and adults, is a stimulant medication like methylphenidate (Ritalin) or amphetamine (Adderall). Guanfacine, however, is a non-stimulant drug — it can target the same symptoms, it just goes about it in a different way.

Still, Dr. Mitrani adds: “We don’t typically start with guanfacine as a medication for ADHD unless the behaviors are more of the problem or there’s concern about starting a stimulant.”

For example, guanfacine may be beneficial for a child who does well academically but has trouble settling down and following rules in class. “I see kids who are really bright, so they don’t have to pay full attention to do well in school but can still struggle with behaviors that are causing a problem,” says Dr. Mitrani. For other kids, “they may benefit from a stimulant for their attention and behaviors, but parents are concerned that a stimulant may result in them not eating, which can impact growth. That’s where I may start with guanfacine.”

For some children, adding guanfacine can also address issues associated with stimulant medications, including sleep problems and the “crash” in mood and behavior that some kids experience at the end of the day, when they’re coming off a stimulant. Guanfacine may make kids drowsy, so it’s usually taken at night, says Dr. Mitrani. That means it can offset side effects of a stimulant by helping kids get tired when it’s time for bed. But some kids take guanfacine in the morning without feeling sleepy during the day, he adds.

Sleepiness: A common side effect of guanfacine is sleepiness or fatigue. But if a child is really tired after taking guanfacine, says Dr. Mitrani, it’s probably not a great fit. “Tiredness is the one side effect we are most concerned with because if it makes you tired, it’s not a good medicine for you.”

If a child is taking guanfacine in addition to a stimulant, consider their whole medication schedule when discussing any concerns with their pediatrician. “For example,” says Dr. Mitrani, “if they don’t take their stimulant on the weekend, but they stay on the guanfacine, they may feel more tired on the weekends than they do during the week because the stimulant is helping balance things out.”

Low blood pressure: Guanfacine can also lower blood pressure, which can cause dizziness. “Most kids tolerate any small drop in blood pressure fine because their hearts are young and healthy and they compensate with an increased heart rate,” Dr. Mitrani says. But other possible side effects related to lower blood pressure (hypotension) include constipation, dry mouth, or headaches.

There are two kinds of guanfacine: immediate-release (IR), which lasts for several hours, and extended-release (ER), which lasts all day.

Immediate-release (IR) guanfacine: Guanfacine IR (previously known by the brand name Tenex) is used off label to treat ADHD and other disorders. Guanfacine IR is absorbed faster, peaks earlier, and lasts for less time than the extended-release version. Children typically take more than one dose per day.

Guanfacine ER (Intuniv): Guanfacine ER is FDA-approved to treat ADHD in children ages 6 through 17, either alone or in addition to stimulants. Guanfacine ER is available in a range of doses, typically starting at 1mg, and is taken once per day.

Notes on dosing: The recommended pediatric dose of guanfacine ER is 1–4mg daily for children 6 to 12. Children 13 to 17 are FDA-approved to receive a dose up to 7mg. But some young children tolerate and benefit from doses above 4mg, says Dr. Mitrani. Still, any amount of the drug should be handled with caution. If a decision is made for a child to stop taking guanfacine, the dose should be tapered off over a period of time, usually several weeks. Stopping the medication abruptly, particularly at a higher dose, can cause a spike in blood pressure, Dr. Mitrani explains.

Short- and long-acting forms of guanfacine are not interchangeable in terms of dosing. For example, if your child is taking guanfacine ER 2mg, that doesn’t mean it would be appropriate for them to make a direct switch to guanfacine IR 2mg — these medicines are not equivalent because of the way they are absorbed. If a child switches medications, their dose must be adjusted.

Guanfacine isn’t the only drug of its class that can be used to help with ADHD symptoms like hyperactivity or impulsivity. Another commonly used alpha-2 agonist is called clonidine (Catapres, Kapvay). Clonidine, FDA-approved to treat ADHD in children ages 6–17, essentially works the same way as guanfacine but tends to be a little more potent. As a result, side effects like sleepiness can be more pronounced, so it’s usually not the first choice, says Dr. Mitrani.

On the positive side, newer versions of clonidine (Onyda XR) are available in liquid form, which makes it possible to control the dose to a finer degree. “With guanfacine, in its long-acting form, you’re working with 1 milligram, 2 milligrams, 3 milligrams, etcetera,” Dr. Mitrani explains. “With the liquid clonidine, you could do 0.15 milligrams or 0.25 milligrams. So, you can optimize the dose, and hopefully, reduce any negative side effects.”

Liquid clonidine, which, like guanfacine ER, lasts 24 hours, is also a good option for kids with sensory issues or an aversion to swallowing pills. Guanfacine ER tablets cannot be crushed or broken because then the medication may be released too quickly. Children must swallow time-release tablets whole.

Guanfacine has been shown to be effective in treating some children with tic disorders. Researchers aren’t entirely sure why guanfacine can reduce tic severity, and their thinking has shifted in recent years. They theorize that the drug’s effects on the prefrontal cortex may help regulate attention and suppress tics.

Some studies show that the short-acting version of guanfacine, which kids typically take two to three times a day, can help manage tics better, says Dr. Mitrani. “Tics wax and wane; they come and go,” he explains. “They can be triggered by being excited, being tired, or being stressed.” Immediate-release guanfacine may be better-suited to address these fluctuations.

Kids with tic disorders often have other disorders, including ADHD. Studies show that guanfacine is more effective for kids with tics and ADHD than kids with tic disorders alone.

Guanfacine can also be prescribed off label to help treat autism. It may be effective in these cases because it helps regulate symptoms that are similar to or associated with ADHD, such as hyperactivity, impulsivity, and distractibility. Researchers estimate that about one-third of children with autism also have ADHD. Guanfacine is also sometimes used to address irritability, oppositional behavior, or problematic repetitive behaviors.