Guanfacine tablets (Tenex) are used alone or in combination with other medications to treat high blood pressure. Guanfacine extended-release (long-acting) tablets (Intuniv) 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.
High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.
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.
Before taking guanfacine,
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.
Guanfacine may cause side effects. Tell your doctor if any of these symptoms or those listed in the SPECIAL PRECAUTIONS section are severe or do not go away:
Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:
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 ( Web Site) 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).
It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. Web Site
Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website ( Web Site) for more information if you do not have access to a take-back program.
In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at Web Site. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.
Symptoms of overdose may include:
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.