- Tablet (extended release): 1 mg, 2 mg, 3 mg, 4 mg
- Tablet (immediate release): 1 mg, 2 mg
Generic name: guanfacine (GWAHN fa seen)
All FDA black box warnings are at the end of this fact sheet. Please consult them before taking this medication.
What is guanfacine and what does it treat?
Guanfacine is a prescription medication that is used to treat attention-deficit hyperactivity disorder (ADHD) in individuals between 6 and 17 years of age. Guanfacine is also used to treat blood pressure in both children and adults.
Symptoms of ADHD interfere with an individual’s ability to function at school or work or in social settings and include:
- Inattention (e.g., making careless mistakes, losing things necessary for tasks)
- Hyperactivity (e.g., inability to sit still)
- Impulsivity (e.g., interrupting or intruding on others)
A person may have severe inattention without hyperactivity or impulsivity.
Guanfacine is used in addition to non-medication treatments to manage ADHD symptoms.
What is the most important information I should know about guanfacine?
Although some symptoms may improve within days of starting guanfacine, it may take several weeks before you notice the full benefits of the medication.
Are there specific concerns about guanfacine and pregnancy?
If you are planning on becoming pregnant, notify your healthcare provider so that he/she can best manage your medications. People living with ADHD who wish to become pregnant face important decisions. There are no well-controlled studies of guanfacine use in pregnant women. Animal studies did not demonstrate evidence of fetal harm. It is important to discuss the risks and benefits of treatment with your doctor and caregivers.
Regarding breastfeeding, caution is advised since guanfacine does pass into breast milk.
What should I discuss with my healthcare provider before taking guanfacine?
- Symptoms of your condition that bother you the most
- If you have thoughts of suicide or harming yourself
- If you experience side effects from your medications, discuss them with your provider. Some side effects pass with time, but others may require changes in the medication.
- Any other psychiatric or medical problems you have, including heart disease
- All other medications you are currently taking (including over the counter products, herbal and nutritional supplements) and any medication allergies you have
- Other non-medication treatment you are receiving, such as talk therapy or substance abuse treatment. Your provider can explain how these different treatments work with the medication.
- If you are pregnant, plan to become pregnant, or are breast-feeding
- If you drink alcohol or use drugs
How should I take guanfacine?
Guanfacine is usually taken one to two times per day. Guanfacine can be taken with or without food. However, taking it with a high fat meal can increase absorption and may increase exposure.
The dose usually ranges from 1 mg to 4 mg per day. Only your health care provider can determine the correct dose for you.
Extended release tablets (Intuniv) should not be crushed, chewed or divided. Swallow the tablet whole.
What happens if I miss a dose of guanfacine?
If you miss a dose of guanfacine take it as soon as you remember, unless it is closer to the time of your next dose. Discuss this with your healthcare provider. Do not double your next dose or take more than what is prescribed.
What should I avoid while taking guanfacine?
Guanfacine may cause dizziness or drowsiness, especially when first starting the medication. Make sure you know how you react to the medication before you drive, operate machinery, or participate in other activities that may be dangerous if you are not alert.
Avoid drinking alcohol or using illegal drugs while you are taking this medication. They may decrease the benefits (e.g., worsen your condition) and increase adverse effects (e.g., sedation) of the medication.
What happens if I overdose with guanfacine?
If an overdose occurs call your doctor or 911. You may need urgent medical care. You may also contact the poison control center at 1-800-222-1222.
Overdosing with guanfacine may cause sleepiness, dizziness, low blood pressure and slow heart rate.
A specific treatment to reverse the effects of guanfacine does not exist.
What are possible side effects of guanfacine?
Common side effects
- Sleepiness, drowsiness, dizziness, headache, irritability
- Low blood pressure
- Nausea, stomach pain, dry mouth, constipation and decreased appetite
Rare/serious side effects
- Very low blood pressure or heart rate
Are there any risks for taking guanfacine for long periods of time?
There are no known problems associated with long term use of guanfacine.
What other medications may interact with guanfacine?
The following medications may increase the levels and effects of guanfacine:
- Increased levels: ketoconazole (Nizoral)
- Increased effects:
- Medications that lower blood pressure or cause sedation (sleepiness)
- Other products containing guanfacine or clonidine (Catapres or Kapvay)
The following medications may decrease the levels and effects of guanfacine: rifampin (Rifadin), carbamazepine (Tegretol), and phenytoin (Dilantin)
Guanfacine may increase the levels and effects of: valproic acid (Depakene, Depakote, Depakote-ER, Stavzor)
How long does it take for guanfacine to work?
It may take four to eight weeks to get the maximum benefit once the right dose is determined. However, improvements in some symptoms may occur sooner.
Summary of FDA Black Box Warnings
There are no FDA black box warnings for guanfacine.
This information is being provided as a community outreach effort of the College of Psychiatric and Neurologic Pharmacists. This information is for educational and informational purposes only and is not medical advice. This information contains a summary of important points and is not an exhaustive review of information about the medication. Always seek the advice of a physician or other qualified medical professional with any questions you may have regarding medications or medical conditions. Never delay seeking professional medical advice or disregard medical professional advice as a result of any information provided herein. The College of Psychiatric and Neurologic Pharmacists disclaims any and all liability alleged as a result of the information provided herein.