Alpha-2 Agonist Drugs for Kids With ADHD

Medically Reviewed by Dan Brennan, MD on May 24, 2022

When kids with ADHD need medicines to help with symptoms like hyperactivity, inattention, or impulsivity, doctors usually suggest stimulants first. But some children don’t respond well to these drugs or have bothersome side effects.

That’s where nonstimulants come into play. Guanfacine (Intuniv) and clonidine (Kapvay) are two nonstimulant drugs that belong to a class of medications called alpha-2 adrenergic agonists. These meds, also referred to as just alpha-2 agonists, may provide a welcome alternative for some kids when other drugs fail. They’re also sometimes used along with stimulants for a better effect.

What Are Guanfacine and Clonidine?

Guanfacine and clonidine were first developed to treat high blood pressure. By affecting nerve impulses, they relax blood vessels and thus reduce blood pressure. But scientists believe they also target an area of the brain that regulates attention and impulsivity.

Overall, research suggests that alpha-2 agonist drugs can improve symptoms in about 55% to 60% of kids with ADHD.

Doctors generally recommend these medications after a child has already tried a stimulant. That’s because a growing body of research shows stimulant drugs tend to work better for ADHD symptoms than alpha-2 agonists.

Researchers who reviewed 133 clinical trials on different ADHD medicines concluded that stimulants were more effective than nonstimulants at reducing symptoms in both children and adults.

The FDA has approved guanfacine and clonidine for children ages 6-17. But some research suggests alpha-2 agonists may also be suitable for younger children.

In a 2021 study of preschool-aged kids with ADHD, 78% of those treated with stimulants had an improvement in symptoms, compared to 66% of those who took an alpha agonist. But the preschoolers who took the alpha-2 agonists reported fewer side effects.

When Do Doctors Prescribe Alpha-2 Agonists?

An alpha-2 agonist medication may be a good option if your child:

  • Doesn’t have much improvement in ADHD symptoms while using a stimulant medicine
  • Can’t tolerate a stimulant’s side effects, such as trouble sleeping, weight loss, headaches, loss of appetite, delayed growth, and stomach pain
  • Has a medical condition that prevents the use of a stimulant (such as a tic disorder or heart issue)
  • Is at risk for stimulant abuse or misuse

Sometimes, guanfacine or clonidine are prescribed along with a stimulant when the stimulant doesn’t work well enough on its own.

Other nonstimulant medications doctors prescribe for ADHD include atomoxetine (Strattera) and viloxazine (Qelbree). Both atomoxetine and viloxazine are a type of antidepressant called selective norepinephrine reuptake inhibitors. Doctors sometimes prescribe other types of antidepressants for ADHD, too.

How Do You Take Guanfacine and Clonidine?

Guanfacine and clonidine both come as long-acting pills. Your doctor will likely start your child on the lowest possible dose and then gradually increase it. How big of an increase will depend on how they respond to the medicine.

Kids take guanfacine once a day, either in the morning or evening. The medicine is available in four dosages: 1 milligram (mg), 2 mg, 3 mg, and 4 mg.

They take clonidine twice a day, once in the morning and once at bedtime. It comes in a 0.1 mg dose or a 0.2 mg dose.

Both medicines must be swallowed whole and can’t be crushed, chewed, or broken.

Your child may have to take guanfacine or clonidine for 4-8 weeks before they notice the full benefits.

Children who need to discontinue treatment with an alpha-2 agonist should taper off their medicine gradually. If they stop suddenly, the medicines can cause withdrawal symptoms, including high blood pressure or heart rate problems.

Short-acting forms of guanfacine (Tenex) and clonidine (Catapres) are FDA-approved for high blood pressure but are sometimes used “off-label” to treat ADHD.

What Are the Possible Side Effects?

Alpha-2 agonist drugs can cause side effects such as:

Some research has suggested that treatment with these drugs may increase the risk for certain heart events. Kids with a family history of heart trouble should tell their doctors before they start guanfacine or clonidine.

These medicines should be used with caution in children who have or are at risk for:

  • Low blood pressure
  • Low heart rate (bradycardia)
  • Fainting
  • Heart block, a problem with electrical signals in your heart that can cause an abnormal heartbeat

How to Decide on an ADHD Medicine

It can be hard to know which medicine will help your child the most. You and your doctor will have to weigh the pros and cons of each treatment option.

Everyone responds to medications differently. So your child may have to try several before you settle on one. And they may need to try new dosages or different medications as they grow.

Parents and teachers can monitor kids to help figure out if a certain drug or dosage is effective. Whether your child has side effects and how bad they are will also affect your treatment preference.

Don’t expect an ADHD medication to eliminate all symptoms. Most kids do best when they also get behavioral therapy, along with support from parents and teachers.

While ADHD medicines like guanfacine and clonidine won’t cure your child, they may allow them to function better at school and at home.

Show Sources


NIH: “Attention-Deficit/Hyperactivity Disorder.”

FDA: “Dealing with ADHD: What You Need to Know.”

Medscape: “The Role of Alpha 2 Agonists in the Attention Deficit/Hyperactivity Disorder Treatment Paradigm.”

American Psychiatric Association: “ADHD: Parents Medication Guide.”

Mental Health Clinician: “Clonidine and guanfacine IR vs ER: Old drugs with 'new' formulations.”

MedlinePlus: “Guanfacine.”

Child Mind Institute: “What Are Nonstimulant Medications for ADHD?”

Current Psychiatry: “Expanding medication options for pediatric ADHD.”

The Lancet Psychiatry: “Comparative efficacy and tolerability of medications for attention-deficit hyperactivity disorder in children, adolescents, and adults: a systematic review and network meta-analysis.”

JAMA: “α2-Adrenergic Agonists or Stimulants for Preschool-Age Children With Attention-Deficit/Hyperactivity Disorder.”

Current Psychiatry Reports: “Alpha-2 Adrenergic Receptors and Attention—Deficit/Hyperactivity Disorder.”

FDA Prescribing Information: “INTUNIV (guanfacine),” “KAPVAY (clonidine hydrochloride).”

American Academy of Pediatrics: “Non-Stimulant Medications Available for ADHD Treatment.”

National Alliance on Mental Illness: “Guanfacine (Intuniv),” “Clonidine (Kapvay and Catapres).”

Cleveland Clinic: “Attention Deficit Hyperactivity Disorder (ADHD) Nonstimulant Therapy (Strattera) & Other ADHD Drugs.”

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