Guanfacine is a non-stimulant medication that may help manage impulse control and attention in people with ADHD, particularly children ages 12 and under.

Guanfacine belongs to the class of medications known as central alpha 2A-adrenergic receptor agonists.

Generally, this class of medications helps open your blood vessels, which helps lower your heart rate and blood pressure.

Researchers have found that guanfacine may help improve the function of the prefrontal cortex, which is the part of your brain that regulates attention and impulse control. For this reason, doctors may prescribe it to treat attention deficit hyperactivity disorder (ADHD).

The Food and Drug Administration (FDA) approved an extended-release version of guanfacine to treat attention deficit hyperactivity disorder (ADHD) in children and adolescents ages 6 to 17 years. For adults, doctors may prescribe it off-label.

Key facts about guanfacine include:

  • It’s more commonly used to treat hypertension and to help prevent serious health conditions such as heart attack and stroke, in people with higher-than-normal blood pressure.
  • It was previously sold in the United States under the brand name Tenex and is currently still available as a generic guanfacine immediate release (IR). When sold under the name Intuniv, it’s used to treat ADHD. While the generic version and Intuniv both contain guanfacine, there are differences in the recommended dosage.
  • Guanfacine is typically only used for ADHD when stimulants like amphetamine-dextroamphetamine (Adderall) are not suitable, not tolerated, or not effective. The medication appears to be most effective in children ages 12 years or younger.

For some people with ADHD, stimulant medications aren’t the best choice. A doctor might consider using a nonstimulant medication like guanfacine for ADHD if:

  • The person is a child between ages 6 and 17 years.
  • Stimulants aren’t working well in managing ADHD symptoms.
  • Stimulants cause too many side effects.
  • The child or adolescent has substance use disorder.
  • The child or adolescent has a medical condition for which stimulants should not be used.

In these cases, a nonstimulant medication like guanfacine may be a good option.

Intuniv is an extended-release (ER) formulation of guanfacine that may be given in addition to stimulants or as part of a treatment program that also includes psychological counseling and educational measures.

Treatment approaches that combine behavioral therapy and medication have shown to be the most effective compared with using either treatment alone. Depending on the person’s age, the recommendations may vary.

While guanfacine ER is not currently approved for use in adults, research shows the medication could be as effective in treating ADHD in adults.

The effectiveness of Intuniv is based on the results of clinical trials in children and adolescents. During these studies, Intuniv was found to decrease scores on the ADHD Rating Scale-IV by an average of 15 to 23 points, compared with 10 to 18 points for those people who received placebo medication. The scale includes scores for hyperactive, impulsive, and inattentive tendencies.

Both guanfacine IR and guanfacine ER contain guanfacine, but they release differently into the body due to a difference in the formulation. However, there is less evidence to support the use of guanfacine IR in the treatment of ADHD.

One study found that guanfacine IR (formerly Tenex) users had significantly higher rates of treatment discontinuation than those taking Intuniv for ADHD.

Even so, some doctors will prescribe guanfacine IR for ADHD. This is known as off-label drug use.

Guanfacine off-label use

Off-label drug use means that a drug that’s FDA approved for one purpose is used for a different purpose that has not been approved.

However, a doctor can still use the drug for the unregulated purpose. This is because the FDA regulates the testing and approval of drugs but not how doctors use drugs to treat their patients. So your doctor can prescribe a drug however they think is best for your care.

If your doctor prescribes a drug for off-label use, you should feel free to ask any questions you may have. You have a right to be involved in any decisions about your care. Examples of questions you may ask include:

  • Why did you prescribe an off-label use of this drug?
  • Are there other approved drugs available that can do the same thing?
  • Will my health insurance cover this off-label drug use?
  • Do you know what side effects I may have from this drug?

Guanfacine ER or Intuniv should be taken as a tablet by mouth. The tablets should not be crushed, chewed, or broken before swallowing.

For Intuniv, your child can often be given a 1-milligram (mg) dose once per day. However, doctors will often begin with the smallest, most effective dose, taking various criteria into consideration.

The typical dosage of guanfacine IR for ADHD is 0.5 mg to 1 mg between one and four times daily. It’s important that you speak with your child’s doctor if you want to stop the medication, as discontinuing may require slow tapering to avoid a rise in blood pressure.

Over the next 4 to 7 weeks, the dose may be slowly increased based on the child’s age and weight. Your child will be monitored for any side effects during this time.

The maximum dosage is between 5 mg and 7 mg per day depending on the child’s weight and age.

It’s important to note that guanfacine IR and Intuniv cannot be substituted for each other on an mg-per-mg basis. While both drugs contain guanfacine, there are differences in how the pills are formulated.

Extended-release medications like Intuniv release slowly into the body over time. Guanfacine IR is an immediate-release drug that releases the medication into the body right away.

Your child’s heart rate and blood pressure will be measured before they begin treatment and periodically during the treatment period.

There are some risks with taking guanfacine. The first is potential side effects, and the second is drug interactions.

Side effects of guanfacine

The most commonly reported side effects of guanfacine include:

Serious side effects may include:

  • lower-than-normal blood pressure (hypotension)
  • increased blood pressure if the medication is stopped suddenly (hypertension)
  • weight gain
  • fainting
  • slower heart rate
  • trouble breathing — call 911 if you or your child experiences this symptom

Drug interactions

Guanfacine can also interact with other medications, including herbal supplements and over-the-counter medications. Taking guanfacine with any of the following drugs or classes of medications may require adjustments to dosage:

  • CYP3A4/5 inhibitors, such as ketoconazole, which includes grapefruit and grapefruit juice
  • CYP3A4 inducers, such as rifampin (Rifadin), which is an antibiotic
  • valproic acid (Depakene), an anticonvulsant medication
  • medications used to treat hypertension (antihypertensive drugs)
  • central nervous system depressants, including alcohol, benzodiazepines, opioids, and antipsychotics

Use caution if you have a history of fainting, heart disease, low blood pressure, depression, or heart block. This medication may complicate your condition or make its symptoms worse.

The most commonly used medications for ADHD are in a class of compounds known as stimulants. These work by increasing dopamine and norepinephrine in the brain. They include:

  • methylphenidate (Ritalin, Concerta)
  • amphetamine-dextroamphetamine (Adderall)
  • dextroamphetamine (Dexedrine)
  • lisdexamfetamine (Vyvanse)

However, some people with ADHD cannot tolerate stimulants. In these cases, a doctor may prescribe nonstimulant medications like guanfacine. Taking these will not increase your dopamine levels, but this means it can take longer to see results. These medications are also less addictive.

Other than guanfacine, which is approved for children and adolescents, there are two nonstimulant drugs FDA approved to treat ADHD in adults:

Learn more about ADHD medications.

Behavioral therapy

In most cases, ADHD treatment also involves behavioral therapy. Therapy is not typically a substitute for the use of medications but rather it’s used in combination with them.

Therapy focuses on ways of thinking and creating healthier behavioral patterns and habits.

It can also help teach kids skills that they can use as they get older. Therapy can address negative behaviors and teach kids how to create positive relationships with adults and peers.

Find out how to tell if your ADHD medication is working.

Why does guanfacine cause weight gain?

Research trials showed that taking extended-release guanfacine led to an average of 0.5 kilograms (kg) or 1 pound (lbs.) increase in weight during the duration of the trial. In one study, a child taking guanfacine gained 16 kg or 35 lbs. in 1 year.

The mechanism of how guanfacine can cause a person to gain weight is not fully understood. However nonstimulant medications like guanfacine do not curb your appetite the way stimulant medications are able to do, so your child may find themselves hungrier while taking guanfacine.

Can you overdose on guanfacine?

It is important to take guanfacine exactly as the doctor prescribes it because an overdose is possible. Symptoms of an overdose include:

  • low blood pressure (hypotension)
  • sleepiness and lethargy
  • slow heartbeat (bradycardia)
  • difficulty breathing

If you think your child may have overdosed on guanfacine, seek medical help immediately. They should be monitored medically for 24 hours to make sure they do not develop more serious symptoms. In severe cases, guanfacine overdose can lead to coma.

Can you use guanfacine for anxiety?

Guanfacine is not FDA approved to treat anxiety. However, at least two studies from 2013 and 2017 have shown that using it to treat anxiety and trauma-related disorders in children and adolescents may be effective and safe.

Learn more about anxiety medications.

Both Guanfacine IR and Intuniv contain guanfacine and may be used to treat ADHD in children, but only Intuniv is FDA approved for this purpose.

Though both Guanfacine IR and Intuniv contain guanfacine, there are differences in how they’re formulated, so be sure you talk with your doctor about your child’s dosage and treatment.

If you or your child has ADHD, your doctor will decide whether to prescribe guanfacine or another medication. Work with your doctor to create a treatment plan that includes medication and behavioral therapy to help manage the ADHD symptoms.