Guanfacine tablets (Tenex brand only) are used alone or in combination with other medications to treat high blood pressure. Guanfacine extended-release (long-acting) tablets (Intuniv brand only) are used as part of a treatment program to control symptoms of attention deficit hyperactivity disorder (ADHD; more difficulty focusing, controlling actions, and remaining still or quiet than other people who are the same age) in children. Guanfacine is in a class of medications called centrally acting alpha2A-adrenergic receptor agonists. Guanfacine treats high blood pressure by decreasing heart rate and relaxing the blood vessels so that blood can flow more easily through the body. Guanfacine extended-release tablets may treat ADHD by affecting the part of the brain that controls attention and impulsivity.
Guanfacine comes as a tablet and as an extended-release tablet to take by mouth. The tablet is usually taken once a day at bedtime. The extended-release tablet is usually taken once a day and should not be taken with a high fat meal. Take guanfacine at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take guanfacine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Swallow the extended-release tablets whole with a small amount of water or another liquid; do not break, chew, or crush them.
Your doctor will probably start you on a low dose of guanfacine and may gradually increase your dose, not more often than once a week if you are taking the extended-release tablets, and not more often than once every 3-4 weeks if you are taking the tablets.
Guanfacine may control your condition, but will not cure it. It may take 2 weeks before you feel the full benefit of guanfacine extended-release tablets. Continue to take guanfacine even if you feel well. Do not stop taking guanfacine without talking to your doctor. If you suddenly stop taking guanfacine, your blood pressure may increase and you may become nervous or anxious. Your doctor will probably decrease your dose gradually.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.
Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medication.
Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are taking guanfacine extended-release tablets, and miss two or more doses in a row, call your doctor.
decreased sexual ability
slow heart rate
Guanfacine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at http://www.fda.gov/Safety/MedWatch] or by phone [1-800-332-1088].
Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
lack of energy
slow heart rate
smaller pupils (black circles in the middle of the eyes)
Keep all appointments with your doctor. Your blood pressure and heart rate should be checked regularly to determine your response to guanfacine.
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
Last Reviewed - 09/01/2010
AHFS® Consumer Medication Information. © Copyright, 2014. The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.