ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.
Overview
It can be used alone or with a stimulant for ADHD.
What it's used for
- ADHD (extended-release)
- High blood pressure (immediate-release)
How to take it
- Swallow extended-release tablets whole. Don't take with a high-fat meal.
- Don't stop suddenly; blood pressure can rebound. Your provider will lower it slowly.
Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.
Side effects
Common side effects
- Sleepiness
- Tiredness
- Low blood pressure
- Dizziness
- Stomach pain
Call 911Fainting or a very slow heartbeat
Call your provider todaySevere headache or fast heartbeat after stopping (rebound high blood pressure)
Warnings
- Don't drive until you know how it affects you.
- Avoid getting dehydrated or overheated.
Other medicines, foods, and alcohol
- Alcohol and sedating medicines add to drowsiness.
- Ketoconazole raises its level; rifampin lowers it.
- Valproate levels can rise.
Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.
Pregnancy and breastfeeding
Talk with your provider.
Missed doses, overdose, and storage
If you miss a dose
Take it as soon as you remember, unless it's almost time for your next dose. Then skip the missed dose. Don't take two doses at once.
If someone takes too much
Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.
Storing it
Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.
Conditions it's used for
Sources
- DailyMed: FDA drug label for Guanfacine (U.S. National Library of Medicine)
- MedlinePlus: Drugs, herbs, and supplements
- FDA: Drugs@FDA
Last updated 2026-11-13.