Guanfacine HCL is a non-stimulant medication used to treat ADHD symptoms in patients 6 to 17 years of age.
Brand Name: Intuniv
What Is Guanfacine? What Does Guanfacine Do for ADHD?
Guanfacine (Brand Name: Intuniv) is a non-stimulant prescription medication used to treat attention deficit hyperactivity disorder (ADHD or ADD). Although the FDA requires all medications to be tested and approved as stand-alone monotherapies, guanfacine is so commonly used in combination with stimulant ADHD medications that it carries an additional FDA approval for use in conjunction with stimulant medications.
The first-line stimulant medications are shown to decrease the frequency of distraction for patients with ADHD. Stimulants may not, however, help with other aspects of ADHD such as hyperactivity, impulsivity, and behavioral and emotional self-control. Guanfacine is in a class of medications called alpha 2a specific adrenergic receptor antagonists or, simply, alpha agonists. These medications activate receptors on nerves that use adrenaline as their neurotransmitter. Adrenaline is familiar to everyone who has ever been frightened. It prepares the brain and the body for flight or for fight. The activation of these receptors tricks the adrenaline nerve into being less active, which in turn leads to lower blood pressure but also a significant decrease in hyperactivity, drive, impulsivity, insomnia, and emotional over-reaction. For these reasons, the stimulants and the alpha agonists are near-perfect complements for the management of ADHD at all ages. The other medication in this class is clonidine, which is also FDA-approved for the treatment of ADHD in children.
Non-stimulant ADHD medications like guanfacine can also be helpful for patients who can’t take stimulants due to undesirable side effects or who don’t experience any benefits from them. People with substance abuse problems may also not be good candidates for this medication.
Unlike some stimulant ADHD medications, guanfacine is not a controlled substance and does not have a high risk of abuse or dependency.
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. It has not been studied and approved by the FDA for the treatment of ADHD in children younger than the age of 6 or in adults over the age of 17.
The immediate-release formulation of guanfacine is used to treat high blood pressure. Its safety has not been studied in children under age 12. Because guanfacine is FDA-approved for adults for something other than ADHD, most clinicians feel comfortable using guanfacine IR and ER off-label for adults with ADHD.
Is Guanfacine the Same Thing as Adderall?
No. Guanfacine and Adderall are very different ADHD medications. Both must be prescribed by a doctor and can be used to treat ADHD symptoms but have different side effects and work in the body in different ways. Adderall is a popular stimulant medication that can be prescribed to patients 6 years and older and works to control distractibility and impulsive behavior. It treats inattention, impulsivity, lack of focus, disorganization, forgetfulness, or fidgeting.
Adderall is a combination medication made up of amphetamine and dextroamphetamine that is also available in a generic form. The FDA has approved a generic version of both the immediate-release (Adderall IR) and extended-release (Adderall XR) versions.
Guanfacine can be prescribed when stimulant ADHD medication fails either due to too many negative side effects or a lack of symptom improvement. It is, however, most often used as an addition to a stimulant because it can benefit symptoms and impairments from ADHD that the stimulant medications do not mange well, such as hyperactivity, impulsivity, sleep disturbances, and emotional over-reactions.
Adderall has been classified by the Drug Enforcement Agency (DEA) as a “Schedule II” medication. Schedule II medications are drugs with a high potential for abuse. Guanfacine is in a class of drugs that is not known to be habit-forming.
What Is the Best Dosage of Guanfacine to Treat ADHD Symptoms?
Guanfacine is available in two formulations:
- Immediate-Release Tablet: Taken up to twice daily. Available in 1mg or 2mg dosages.
- Extended-Release Tablet: (Guanfacine ER, Brand Name: Intuniv) Taken once daily in the morning or evening at approximately the same time each day. Tablets are available in 1mg, 2mg, 3mg, and 4mg dosages.
The optimal dosage varies patient by patient and by the condition being treated. Your doctor may adjust your dosage weekly by 1mg increments until you or your child experience the best response. The right dose is the one with that gives you (or your child) the most improvement in symptoms without side effects (or with the fewest).
Guanfacine should not be taken with a high-fat meal. This can speed up the release of medication, and increase the risk of side effects. Tablets should be swallowed whole with water or other liquids, and never crushed or chewed. If you miss a dose, you should take it as soon as possible, unless it is already time for your next dose. You should not take two doses of guanfacine at the same time. Contact your doctor if you have questions about skipped pills.
Do not drink alcohol while taking this drug.
When discontinuing treatment, or decreasing dosage, patients should work with a doctor to gradually taper the level of medication by no more than 1mg every 3 to 7 days. Stopping guanfacine suddenly can theoretically create withdrawal symptoms including increased heart rate and high blood pressure. Because people who have ADHD are forgetful and may sometimes forget doses of medications like guanfacine, the FDA did sudden-cessation trials to assess the safety of suddenly stopping an alpha agonist. No rebound high blood pressure or fast heart rate were seen. Nonetheless, when a person stops an alpha agonist, it is strongly recommended to taper off the medication as a precaution.
Before starting or refilling a guanfacine prescription, read the medication guide included with your pills, as it may be updated with new information. This guide should not replace a conversation with your doctor. Your doctor can review you or your child’s medical history, other diagnoses, and other prescriptions for possible interactions and take into account other important considerations. If you have questions, ask your doctor or pharmacist before you begin taking the medication.
As with all medications, follow your guanfacine prescription instructions exactly.
What are the Side Effects of Guanfacine?
Most people taking guanfacine do not experience side effects. That said, the most common guanfacine side effects are:
- sedation or tiredness
- low blood pressure usually seen as dizziness when standing up quickly
- dry mouth
- irritability seen in 1-2% of people that does not go away with time. If severely irritable after starting guanfacine, the patient should stop the medication and call their physician
Other less common side effects include
- slow heart rate
- stomach pain
Serious side effects of guanfacine also include low blood pressure or heart rate, fainting, sleepiness, or withdrawal symptoms. Taking guanfacine may impair your or your teenager’s ability to drive, operate machinery, or perform other potentially dangerous tasks. If side effects are bothersome or continue to persist, talk to your doctor.
Guanfacine and Heart or Blood Pressure Related Problems
Report to your doctor any heart-related problems or a family history of heart and blood pressure problems. Patients with structural cardiac abnormalities, renal failure, and serious heart problems could experience complications while taking guanfacine. Physicians should monitor vital signs closely during treatment. Call your doctor immediately if you or your child experience warning signs such as chest pain, shortness of breath, or fainting while taking guanfacine.
The above is not a complete list of potential side effects. If you notice any health changes not listed above, discuss them with your doctor or pharmacist.
What Precautions are Associated with Guanfacine?
- You should not take guanfacine if you have an allergy to guanfacine or any of its ingredients.
- Proceed with caution if you have kidney problems, a history of fainting, heart problems, or a history of stroke.
- Avoid becoming overheated or dehydrated while taking guanfacine.
- If you’re thinking of becoming pregnant, discuss the use of guanfacine with your doctor. Animal studies indicate a potential risk of fetal harm.
- It is not known if guanfacine is passed through breastmilk, so nursing mothers are usually instructed not to take this medication.
Store guanfacine in a secure place out of the reach of children, and at room temperature.
Do not share your guanfacine prescription with anyone, even another person with ADHD. Sharing prescription medication is illegal, and can cause harm.
What Should I Know Before Taking Guanfacine?
Be sure and discuss all other active prescription medications with your doctor. Guanfacine can cause dizziness and exacerbate the drowsiness created by depressants including alcohol, barbiturates, antihistamines, or other sedatives.
It’s also important to share information about all vitamin or herbal supplements (especially St. John’s wort), and non-prescription medications (acetaminophen, ibuprofen, etc.) you take with the pharmacist when you fill your prescription and let healthcare providers know you are taking guanfacine before undergoing surgery or having lab tests.
Note: The information in this article is not a complete list of all possible drug interactions.
Guanfacine and Other Medications: More Information
- Download: Take Charge of Your Child’s Medication
- Read: Intuniv – Answers to Your ADHD Medication Questions
- Download: How Do We Know the Medication Is Working?
- Find: ADHD Specialists and Clinics Near You
Guanfacine- guanfacine hydrochloride tablet. Daily Med (2017). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6fdcebac-0a5a-4858-b0e6-87f77ba53bf1
Guanfacine tablet- extended release. Daily Med (2019). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=301f01a7-2b0a-cfba-9c3d-a1dd831785a3
Newcorn, Jeffrey, et al. Extended‐release guanfacine hydrochloride in 6–17‐year olds with ADHD: a randomised‐withdrawal maintenance of efficacy study. The Association for Child and Adolescent Mental Health (2016). https://acamh.onlinelibrary.wiley.com/doi/full/10.1111/jcpp.12492