Generic Name: guanfacine, Oral tablet

Intuniv

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  • Intuniv
SECTION 1 of 4

Highlights for guanfacine

Oral tablet
1

Guanfacine immediate-release tablets are used to help lower your blood pressure.

2

The recommended starting dose is 1 mg taken at bedtime. Your doctor may increase your dose after 3–4 weeks to help you bring your blood pressure down to goal.

3

This medication may cause a rash or peeling skin. If you experience these side effects, stop taking guanfacine and call your doctor.

4

Common side effects include dry mouth, sleepiness, and dizziness.

5

This medication needs to be stopped slowly. Your doctor may gradually decrease your dose. If you stop taking it suddenly, it can cause your blood pressure to spike too high.

IMPORTANT INFORMATION

May cause sedation

Sedation is more likely to happen early in treatment or when your dose increases. Don’t drive a car, operate machinery, or do similar activities that require alertness until you know how guanfacine will affect you.

Alcohol warning

Avoid drinking alcohol while taking guanfacine. Your tolerance to alcohol may be reduced, which will increase its effects. Alcohol can also make guanfacine stay in your body longer. This could lead to worse side effects from the drug.

Warning for stopping the drug

Don’t stop taking guanfacine without talking to your doctor first. This medication needs to be stopped slowly. Your doctor may gradually decrease your dose. If you stop taking it abruptly, it can cause your blood pressure to go up too high.

Drug Features

Guanfacine is a prescription drug. It’s available in these forms: oral immediate-release tablet (high blood pressure) and oral extended-release tablet (attention deficit hyperactivity disorder, ADHD).

Guanfacine is available in its generic form. Generic drugs usually cost less. In some cases they may not be available in every strength or form as the brand. Talk to your healthcare provider to see if the generic will work for you.

This drug may be used as part of a combination therapy. That means you may need to take it with other drugs.

Why It's Used

Guanfacine immediate-release tablets are used to help lower your blood pressure. Having high blood pressure can lead to serious health conditions, such as heart attack and stroke.

How It Works

Guanfacine works by helping to open your blood vessels. This helps lower your heart rate and blood pressure.

More Details

How It Works

Guanfacine works by helping to open your blood vessels. This helps lower your heart rate and blood pressure.

It belongs to a class of drugs called central alpha 2A-adrenergic receptor agonists.

SECTION 2 of 4

guanfacine Side Effects

Oral tablet

Most Common Side Effects

The most common side effects that occur with guanfacine are:

  • dry mouth

  • sleepiness

  • dizziness

  • constipation

  • weakness

  • headache

  • trouble sleeping

Mild side effects may go away within a couple of weeks. Talk to your doctor or pharmacist if they’re more severe or don’t go away.

Serious Side Effects

If you experience any of these serious side effects, call your doctor right away. If your symptoms are potentially life threatening, or if you think you’re experiencing a medical emergency, call 9-1-1.

  • skin rash with peeling skin. If you experience a rash, stop taking guanfacine and call your doctor.

Pharmacist's Advice
Healthline Pharmacist Editorial Team

Guanfacine may cause sedation, especially early in treatment or when your dose is increased. Don’t drive a car, operate heavy machinery, or do similar activities that require alertness until you know how guanfacine will affect you.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this information includes all possible side effects. This information is not a substitute for medical advice. Always discuss possible side effects with a healthcare provider who knows your medical history.
SECTION 3 of 4

guanfacine May Interact with Other Medications

Oral tablet

Guanfacine can interact with other medications, herbs, or vitamins you might be taking. That’s why your doctor should manage all of your medications carefully. If you’re curious about how this drug might interact with something else you’re taking, talk to your doctor or pharmacist.

Note: You can reduce your chances of drug interactions by having all of your prescriptions filled at the same pharmacy. That way, a pharmacist can check for possible drug interactions.

Alcohol Interaction

Avoid drinking alcohol while you’re taking this medication. Your body processes alcohol and guanfacine in similar ways. That means that if you drink alcohol, this drug might take longer to leave your body. You could experience worse side effects.

Guanfacine may lower your tolerance to alcohol, meaning you’ll feel the sedative effects of alcohol more quickly. This can be dangerous and includes symptoms such as slowed reflexes, poor judgment, and sleepiness.

Medications that Might Interact with This Drug

Drugs that affect CYP3A4 enzyme

These include both inhibitors and inducers.

Examples are:

  • CYP3A4 inhibitors:
    • Clarithromycin
    • Erythromycin
    • Ketoconazole
    • Itraconazole
    • Diltiazem
    • Verapamil
  • CYP3A4 inducers:
    • Rifampin
    • Phenytoin
    • Carbamazepine
    • St. John’s wort

CYP3A4 is an enzyme that helps your body process drugs. Some drugs slow down the enzyme’s ability to process drugs such as guanfacine. These drugs are known as CYP3A4 inhibitors. Other drugs speed up the enzymes ability to process drugs. These drugs are known as CYP3A4 inducers.

If you’re taking a CYP3A4 inhibitor, your dose of guanfacine may be lowered to half the regular dose. If you stop taking the drug, your dose of guanfacine will be increased to the regular dose.

If you’re taking a CYP3A4 inducer, your dose of guanfacine may be double the regular dose. If you stop taking the drug, your dose of guanfacine may be lowered over 1–2 weeks.

Drugs that slow brain activity

Examples are:

  • Benzodiazepines, such as:
    • lorazepam
    • diazepam
  • Opioid pain killers, such as:
    • morphine
    • codeine
  • Sleep medications, such as:
    • zolpidem
    • eszopiclone

Taking guanfacine with other medications that slow brain activity can lead to increased sleepiness and mental slowing.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs interact differently in each person, we cannot guarantee that this information includes all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare provider about possible interactions with all prescription drugs, vitamins, herbs and supplements, and over-the-counter drugs that you are taking.

People with kidney disease

Having kidney disease may cause guanfacine to build up in your body, which may cause serious side effects. Your doctor may reduce your dose of the drug if you have serious kidney disease.

People with liver disease

Having liver disease can cause guanfacine to build up in your body, which may cause serious side effects. Your doctor may reduce your dose of the drug if you have serious liver disease.

People with heart problems

Guanfacine can affect your heart and blood vessels. Tell your doctor if you have heart problems, such as a history of heart attack or stroke.

Pregnant women

Guanfacine is a pregnancy category B drug. That means two things:

  1. Studies of the drug in pregnant animals haven’t shown risk to the fetus.
  2. There aren’t enough studies done in pregnant women to show the drug poses a risk to the fetus.

Tell your doctor if you’re pregnant or plan to become pregnant. Guanfacine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. 

Women who are nursing

It isn’t known if guanfacine passes through breast milk. If it does, it could cause side effects in a breastfeeding child.

You and your doctor may need to decide whether you’ll take guanfacine or breastfeed.

For Seniors

Guanfacine hasn’t been studied in people over the age of 65 years.

For Children

Guanfacine hasn’t been proven to be safe and effective in people younger than 12 years old. It isn’t recommended for this age group.

Allergies

This medication may cause an allergic rash. Stop taking guanfacine and call your doctor if you develop a rash.

Don’t take this drug again if you’ve ever had an allergic reaction to it. Taking it again could be fatal.

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How to Take guanfacine (Dosage)

Oral tablet

All possible dosages and forms may not be included here. Your dose, form, and how often you take it will depend on:

  • your age
  • the condition being treated
  • how severe your condition is
  • other medical conditions you have
  • how you react to the first dose

What Are You Taking This Medication For?

High blood pressure
Form: Oral immediate-release tablet
Strengths: 1 mg and 2 mg
Adult Dosage (ages 18 years and older)
  • The recommended starting dose is 1 mg taken at bedtime.
  • Your doctor may increase your dose after a couple of weeks to help you bring your blood pressure down to goal.
Child Dosage (ages 0-17 years)

A safe and effective dosage hasn’t been established for this age group.

Special Considerations

Kidney Disease: Guanfacine is cleared from your body by your kidneys. Your doctor may need to reduce your dose if you have serious kidney disease so the drug doesn’t build up in your body and cause dangerous side effects.

Liver Disease: Guanfacine is cleared from your body by your liver. Your doctor may need to reduce your dose if you have serious liver disease so the drug doesn’t build up in your body and cause dangerous side effects.

Disclaimer: Our goal is to provide you with the most relevant and current information. However, because drugs affect each person differently, we cannot guarantee that this list includes all possible dosages. This information is not a substitute for medical advice. Always to speak with your doctor or pharmacist about dosages that are right for you.
Pharmacist's Advice
Healthline Pharmacist Editorial Team

Guanfacine comes with risks if you don’t take it as prescribed by your doctor.

If You Miss Doses or Don’t Take It on Schedule

Your condition may not improve and may even get worse.

If You Stop Taking It Suddenly

You may experience an increase in blood pressure, which can be dangerous for your health. Talk to your doctor before stopping this medication.

If You Take Too Much

You may experience serious side effects, including:

  • drowsiness
  • low energy
  • low heart rate
  • low blood pressure

Get immediate medical attention if you take or think you’ve taken too much guanfacine.

What to Do if You Miss a Dose

If you miss a dose, take it as soon as you can. However, if it’s just a few hours until your next dose, skip the missed dose and take the next dose on schedule.

Never try to catch up by taking two doses at once. This could result in toxic side effects.

Guanfacine is a long-term drug treatment.

Important Considerations for Taking Guanfacine
timing Guanfacine may cause drowsiness. It’s usually recommended that you take it at bedtime
can crush You can cut or crush the immediate-release tablet
storage Store at room temperature. Keep in temperatures from 68–77°F (20–25°C) See Details
refillable Prescription is refillable
travel Travel See Details
clinical monitoring Clinical Monitoring See Details

Store at room temperature. Keep in temperatures from 68–77°F (20–25°C)

Keep guanfacine away from light and high temperature and out of the reach of children.

Note: Keep your medications away from areas where they could get wet, such as bathrooms. Store them away from moisture and damp locations.

Travel

When traveling with your medication:

  • Always carry it with you or in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t hurt this medication.
  • You may need to show your pharmacy’s preprinted label to identify the medication. Keep the original prescription-labeled box with you when traveling.

Clinical Monitoring

Your doctor may monitor your blood pressure at your appointments. You can also check your blood pressure at home. If you’re checking your blood pressure at home, it’s helpful to keep a diary of the date, time of day, and your blood pressure reading. Bring this log with you to your doctor visits.

Are There Any Alternatives?

There are other drugs available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.

What does the pill look like?

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Content developed in collaboration with University of Illinois-Chicago, Drug Information Group

Medically reviewed by Creighton University, Center for Drug Information and Evidence-Based Practice on June 25, 2015

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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