Generic Name: guanfacine (GWAHN fa seen)Brand Names: Intuniv, Tenex
Guanfacine reduces nerve impulses in your heart and blood vessels. Guanfacine works by relaxing blood vessels, which lowers blood pressure and improves blood flow.
Guanfacine is used to treat high blood pressure (hypertension). It is sometimes given together with other blood pressure medications.
Guanfacine is also used to treat attention deficit hyperactivity disorder (ADHD) in children who are at least 6 years old.
Guanfacine may also be used for other purposes not listed in this medication guide.
Before you take guanfacine, tell your doctor if you have heart disease, heart block, coronary artery disease or a history of stroke, low blood pressure, kidney or liver disease, or if you have recently had a heart attack.Guanfacine can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.
Avoid becoming overheated or dehydrated during exercise and in hot weather. Avoid drinking alcohol.
To be sure this medication is helping your condition and not causing harmful effects, your doctor will need to check your progress on a regular basis. Your blood pressure and heart rate may also need to be checked. Do not miss any follow-up visits to your doctor.
If you are being treated for high blood pressure, keep using this medication even if you feel fine. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.
Tell your doctor if you regularly use other medicines that make you sleepy. They can add to sleepiness caused by guanfacine.
If you have any of these other conditions, you may need a dose adjustment or special tests to safely use this medication:
heart disease or heart block;
coronary artery disease or a history of stroke;
low blood pressure;
if you have recently had a heart attack.
Take this medication exactly as prescribed by your doctor. Do not take it in larger amounts or for longer than recommended. Follow the directions on your prescription label.
Your doctor may occasionally change your dose to make sure you get the best results from this medication.
If you take Intuiv to treat ADHD, take your dose in the morning.
If you take Tenex to treat hypertension, you may need to take your dose at bedtime if guanfacine causes severe drowsiness. Follow your doctor's instructions.Do not crush, chew, or break an Intuiv extended-release tablet. Swallow the pill whole. Breaking the pill may cause too much of the drug to be released at one time.
If there are any changes in the brand, strength, or type of guanfacine you use, your dosage needs may change. Always check your refills to make sure you have received the correct brand and type of medicine prescribed by your doctor. Ask the pharmacist if you have any questions about the medicine you receive at the pharmacy.
To be sure this medication is helping your condition and not causing harmful effects, your doctor will need to check your progress on a regular basis. Your blood pressure and heart rate may also need to be checked. Do not miss any follow-up visits to your doctor.Do not stop taking this medication without first talking to your doctor. If you stop taking guanfacine suddenly, your condition may become worse and you could have unpleasant symptoms.
If you are being treated for high blood pressure, keep using this medication even if you feel fine. High blood pressure often has no symptoms. You may need to use blood pressure medication for the rest of your life.Store this medication at room temperature away from moisture, heat, and light.
See also: Guanfacine dosage in more detail
Take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. Do not take extra medicine to make up the missed dose.
Call your doctor for instructions if you miss more than 2 doses in a row.
Overdose symptoms may include drowsiness, dizziness, slow heart rate, or feeling like you might pass out.
Avoid taking guanfacine with a high-fat meal.Guanfacine can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.
Avoid becoming overheated or dehydrated during exercise and in hot weather while you are taking guanfacine.Avoid drinking alcohol. It can increase some of the side effects of guanfacine.
fast or slow heart rate;
pounding heartbeats, chest tightness;
numbness or tingling; or
feeling like you might pass out.
Less serious side effects may include:
drowsiness, dizziness, tired feeling;
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Usual Adult Dose for Hypertension:
Initial dose: 1 mg orally once a day at bedtime, when given alone or in combination with another antihypertensive drug. Maintenance dose: 1 to 3 mg orally once a day at bedtime.
Usual Pediatric Dose for Attention Deficit Disorder:
Only the guanfacine extended-release formulation is indicated for ADHD.Children 6 to 17 years of age:Initial dose: 1 mg extended-release orally once a day in the morningDosage should be adjusted in increments of no more than 1 mg/week.Maintenance dose: 1 to 4 mg extended-release orally once daily in the morning, depending on clinical response and tolerability.
Tell your doctor about all other medications you use, especially any other blood pressure medications, or:
dexamethasone (Decadron, Hexadrol);
diclofenac (Arthrotec, Cataflam, Voltaren, Flector Patch, Solareze);
St. John's wort;
isoniazid (for treating tuberculosis);
valproic acid (Depakene, Stavzor);
an antibiotic such as clarithromycin (Biaxin), dalfopristin/quinupristin (Synercid), erythromycin (E.E.S., EryPed, Ery-Tab, Erythrocin), rifampin (Rifadin, Rifater, Rifamate), or telithromycin (Ketek);
antifungal medication such as clotrimazole (Mycelex Troche), itraconazole (Sporanox), ketoconazole (Nizoral), or voriconazole (Vfend);
an antidepressant such as nefazodone;
a barbiturate such as butabarbital (Butisol), secobarbital (Seconal), pentobarbital (Nembutal), or phenobarbital (Solfoton);
a calcium channel blocker such as diltiazem (Cartia, Cardizem), felodipine (Plendil), nifedipine (Nifedical, Procardia), verapamil (Calan, Covera, Isoptin, Verelan), and others;
HIV or AIDS medicine such as atazanavir (Reyataz), delavirdine (Rescriptor), efavirenz (Sustiva), etravirine (Intelence), fosamprenavir (Lexiva), indinavir (Crixivan), nelfinavir (Viracept), nevirapine (Viramune), saquinavir (Invirase), or ritonavir (Norvir); or
seizure medication such as carbamazepine (Carbatrol, Tegretol), felbamate (Felbatol), oxcarbazepine (Trileptal), phenytoin (Dilantin), or primidone (Mysoline).
This list is not complete and there may be other drugs that can interact with guanfacine. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.