What is guanfacine?
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 may also be used for other purposes not listed in this medication guide.
What should I discuss with my healthcare provider before taking guanfacine?
You should not use this medication if you are allergic to guanfacine.
Before taking guanfacine, tell your doctor if you are allergic to any drugs, or if you have:
If you have any of these conditions, you may need a dose adjustment
or special tests to safely take guanfacine.
FDA pregnancy category B. This medication is not expected to be harmful to an
unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.
It is not known whether guanfacine passes into breast milk or if it could harm a
nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a
baby.
How should I take guanfacine?
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.
Guanfacine can cause drowsiness and should be taken at bedtime unless your doctor
has told you otherwise.
Your doctor may occasionally change your dose to make sure you get the best results from
this medication.
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.
To be sure this medication is helping your condition, your blood pressure will need to be
checked on a regular basis. Do not miss any scheduled appointments.
Keep using this medicine as directed, even if you feel well. High blood pressure often has
no symptoms, so you may not know when your blood pressure is high. 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.
What happens if I miss a dose of guanfacine?
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.
Where can I get more information about guanfacine?
Your pharmacist has information about guanfacine written for health professionals that you may read.
What are the possible side effects of guanfacine?
Get emergency medical help if you have any of these
signs of an allergic
reaction:
hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have a serious side effect such as:
Less serious side effects may include:
-
drowsiness, dizziness;
-
dry mouth;
-
headache;
-
sleep problems (insomnia);
-
weakness;
-
constipation, diarrhea;
-
stomach pain;
-
impotence, loss of interest in sex; or
-
mild itching or skin rash.
This is not a complete list of side effects and others may occur. Tell
your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.
What is the most important information I should know about guanfacine?
You should not use this medication if you are allergic to guanfacine.
Before taking guanfacine, tell your doctor if you have heart disease, coronary artery
disease or a history of stroke, kidney disease, liver disease, or if you have recently had a heart
attack.
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.
To be sure this medication is helping your condition, your blood pressure will need to be
checked on a regular basis. Do not miss any scheduled appointments.
Avoid drinking alcohol. It can increase some of the side effects of guanfacine.
Guanfacine can cause drowsiness and should be taken at bedtime unless your doctor
has told you otherwise.
Tell your doctor if you regularly use other medicines that make you sleepy (such as cold
or allergy medicine, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for
seizures, depression, or anxiety). They can add to sleepiness caused by guanfacine.
What should I avoid while taking guanfacine?
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 drinking alcohol. It can increase some of the side effects of guanfacine.
Tell your doctor if you regularly use other medicines that make you sleepy (such as cold
or allergy medicine, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for
seizures, depression, or anxiety). They can add to sleepiness caused by guanfacine.
What other drugs will affect guanfacine?
The following drugs can interact with guanfacine. Tell your doctor if you are using any of
these:
-
a barbiturate such as amobarbital (Amytal), butabarbital (Butisol),
mephobarbital (Mebaral), secobarbital (Seconal), or phenobarbital (Luminal, Solfoton);
-
diazepam (Valium) or similar medicines such as alprazolam
(Xanax), lorazepam (Ativan), temazepam (Restoril), triazolam (Halcion), and others; or
-
phenothiazines such as chlorpromazine (Thorazine),
mesoridazine (Serentil), prochlorperazine (Compazine), thioridazine (Mellaril), and others.
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.
What happens if I have an overdose of guanfacine?