What is guanfacine?
An extended-release version of guanfacine is approved by the U.S. Food and Drug Administration (FDA) to treat attention deficit hyperactivity disorder (ADHD) in children and adolescents ages 6 through 17. Intuniv is the brand name of guanfacine as a medication for ADHD.
Guanfacine is typically only used for ADHD when stimulants like amphetamine-dextroamphetamine (Adderall) aren’t suitable, not tolerated, or not effective. The medication appears to be most effective in children 12 or younger.
While Tenex and Intuniv both contain guanfacine, there are differences in recommended dosage.
In some cases, stimulant medications aren’t the best choice. A doctor might consider using a nonstimulant medication like guanfacine for ADHD if:
- stimulants aren’t working well to control ADHD symptoms
- stimulants cause too many side effects
- your child or teen has problems with substance abuse
- your child or teen has a medical condition for which stimulants shouldn’t be used
For these people, a nonstimulant drug like guanfacine may be a better option. Intuniv is an extended-release (ER) formula of guanfacine. Currently, guanfacine ER is FDA approved only for use in children who are 6 through 17 years old.
Intuniv is also approved as an additional therapy to stimulant medications. Guanfacine may be given in addition to stimulants to help better control ADHD symptoms.
Guanfacine must be used as part of a treatment program that also includes psychological counseling and educational measures.
In 2009, the FDA approved guanfacine ER under the brand name Intuniv for treating ADHD in children 6 to 17 years old.
The efficacy 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 17 to 21 points, compared 9 to 12 points for a placebo. The scale includes scores for hyperactive, impulsive, and inattentive tendencies.
Although guanfacine immediate release (Tenex) works the same way in the body as guanfacine ER, there is less evidence overall to support the use of Tenex in the treatment of ADHD. One study found that Tenex users had significantly higher rates of treatment discontinuation than those taking Intuniv for ADHD.
Even so, some doctors will prescribe Tenex for ADHD. This is known as off-label drug use.
About off-label drug use
Off-label drug use means that a drug that’s been approved by the FDA for one purpose is used for a different purpose that hasn’t been approved. However, a doctor can still use the drug for that 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. Learn more about off-label prescription drug use.
If your doctor prescribes a drug for you for an 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 is taken as a tablet by mouth. The tablets shouldn’t be crushed, chewed, or broken before swallowing.
For Intuniv, a child is typically given a dose of 1 milligram (mg) once per day. The typical dosage of Tenex for ADHD is 0.5 mg between one and four times daily.
Over the next four to seven 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 4 to 7 mg per day depending on the child’s weight and age.
It’s important to note that Tenex and Intuniv can’t be substituted for each other on a 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. Tenex 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.
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
- slower heart rate
- trouble breathing — call 911 if you or your child experiences this symptom
Guanfacine can 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 dose:
- CYP3A4/5 inhibitors, such as ketoconazole. This 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 include:
- methylphenidate (Ritalin, Concerta)
- amphetamine-dextroamphetamine (Adderall)
- dextroamphetamine (Dexedrine)
- lisdexamfetamine (Vyvanse)
There are two nonstimulant drugs approved by the FDA to treat ADHD in adults:
- atomoxetine (Strattera)
- clonidine (Kapvay)
Nonstimulants are often considered less effective than stimulants, but they’re also less addictive.
Behavioral therapy is also important for treating ADHD, especially in children. Therapy focuses on ways of thinking and creating healthier behavioral patterns and habits.
Behavioral therapy can help to teach kids skills that they’ll use as they get older. Therapy can address problematic behaviors and teach kids to create positive relationships with adults and peers.
Both Tenex and Intuniv contain guanfacine and may be used to treat ADHD in children, but only Intuniv is approved by the FDA for this purpose.
Though both Tenex and Intuniv contain guanfacine, there are differences in how they’re formulated, so make sure you talk to 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.
Meet with your doctor to create a treatment plan that includes medication and behavioral therapy to manage the symptoms of ADHD.