Medically reviewed by Jessica Swirble, PharmD
Last updated on March 27, 2025
Drug Information | Side Effects | Use & Dosage | Request an Online Prescription
Guanfacine is a medication primarily used to treat attention deficit hyperactivity disorder (ADHD) in children and teenagers. Extended-release guanfacine tablets are prescribed as a treatment for attention-deficit hyperactivity disorder (ADHD) in children.
Guanfacine is prescribed for the treatment of ADHD as part of a comprehensive treatment plan that may include other therapies such as behavioral therapy. It is also used to lower blood pressure in patients with hypertension (high blood pressure).
Guanfacine belongs to a class of medications known as alpha-2 adrenergic agonists. It works by stimulating certain receptors in the brain, which helps to improve attention, impulse control, and behavior in individuals with ADHD. In the treatment of hypertension, guanfacine works by relaxing blood vessels, thereby reducing blood pressure.
Guanfacine is available as an oral tablet or extended-release tablet. It can usually be taken with or without food. Immediate-release tablets should be taken at bedtime, as they cause drowsiness, while extended-release guanfacine can be taken at any time.
Do not take extended-release guanfacine with high-fat meals.
Follow your healthcare provider's instructions regarding the dosage and administration of guanfacine.
The time it takes to notice the effects of guanfacine may vary depending on the individual and the condition being treated. Improvement in ADHD symptoms may be noticed within a few weeks of starting treatment, while the effects on blood pressure may be observed sooner. It's important to continue taking guanfacine as prescribed, even if you don't notice immediate changes.
Guanfacine may also be prescribed off-label for conditions such as anxiety disorders, tic disorders, and post-traumatic stress disorder (PTSD). Discuss any alternative uses with your healthcare provider.
Guanfacine is available as an oral tablet or extended-release tablet.
It is available under its generic name, guanfacine.
Guanfacine is only available via prescription. You must have a written prescription from a licensed healthcare provider to obtain this medication.
The use of guanfacine has been shown to cause side effects in some patients.
Common mild side effects of guanfacine use include:
More severe side effects include:
Seek medical attention immediately if you experience any severe symptoms while taking guanfacine. If you experience mild side effects that become severe or do not go away after a few days, speak to a healthcare provider right away.
Tell your healthcare provider about any existing medical conditions, allergies, or other medications you are taking before starting treatment with guanfacine. This includes prescription drugs, over-the-counter medications, and dietary supplements, as they may interact with this drug.
Tell your provider if you are taking these medications or supplements:
You should also mention medical conditions such as:
If you are pregnant, planning to become pregnant, or breastfeeding, consult your healthcare provider before using guanfacine to assess potential risks and benefits.
You can follow your regular diet while taking guanfacine. Avoiding activities requiring mental alertness, such as driving or operating heavy machinery, is essential until you know how guanfacine affects you. Guanfacine can cause drowsiness, dizziness, and lightheadedness.
Avoid consuming alcohol while taking guanfacine, as it may increase the risk of side effects such as drowsiness and dizziness.
Avoid eating grapefruit or drinking grapefruit while taking guanfacine. Grapefruit can increase the effects of guanfacine, leading to more side effects.
Extended-release guanfacine should not be taken with a high-fat meal.
Your healthcare provider will provide specific instructions regarding the use of guanfacine with food, beverages, and other medications. It's essential to follow their guidance to ensure the effectiveness of the treatment and minimize the risk of side effects.
If you suspect an overdose of guanfacine or experience severe symptoms, seek immediate medical attention or contact a poison control center. Symptoms of an overdose may include drowsiness, dizziness, fainting, slow heart rate, and difficulty breathing.
If an individual has collapsed, is having seizures, or is unresponsive, call 9-1-1 immediately.
Guanfacine is available in the following forms:
The typical starting dose of guanfacine can vary based on several factors, including the condition being treated, the severity of the condition, and individual patient characteristics. It's crucial to adhere to your healthcare provider's guidance regarding dosage and administration.
For attention deficit hyperactivity disorder (ADHD) in children and adolescents aged 6 to 17 years old, the typical starting doses may be:
For adults with hypertension (high blood pressure), the typical starting dose may be:
Your healthcare provider will assess your medical history, current medications, and response to treatment to determine the most suitable dose for you.
Guanfacine should be taken exactly as prescribed by your healthcare provider. Avoid exceeding the recommended dose or altering the treatment duration without consulting your provider.
If you have any questions about your dosage, contact your healthcare provider. If you want to talk to a provider right away, book an online doctor appointment on Sesame to discuss your concerns.
If you miss a dose, take it as soon as you remember it. If it's almost time for another dose of guanfacine, skip the missed dose and take your next dose as scheduled. Do not take or apply a double dose of guanfacine.
Do not discontinue or alter your guanfacine dosage without consulting with your healthcare provider. Guanfacine must be discontinued slowly. Withdrawal symptoms and rebound hypertension may occur if use is discontinued suddenly.
Follow your healthcare provider's instructions regarding dosing and other recommendations for taking guanfacine.
Store guanfacine as directed by your healthcare provider or pharmacist. Proper storage is essential to maintain the medication's effectiveness. Guanfacine should be stored at room temperature, away from excessive heat, light, and moisture.
Keep the medication out of the reach of children and ensure that the container is tightly closed.