Guanfacine (Intuniv)
A non-stimulant ADHD medication, often used on its own or added to a stimulant.
What it treats
Guanfacine is approved by the U.S. Food and Drug Administration to treat attention-deficit hyperactivity disorder, usually shortened to ADHD, in its extended-release form. The approval covers children and adolescents, and prescribers also use it in adults.
Guanfacine was originally a blood pressure medication, and the immediate-release form is still used for blood pressure. This guide focuses on the extended-release form used for ADHD. When guanfacine is discussed as an ADHD medication, the extended-release version is what is meant.
Prescribers also use guanfacine in ways the label doesn't formally list, which is called an off-label use, meaning a purpose that evidence and practice support even though the label doesn't name it. It is sometimes used to help with tics, and it is sometimes used when ADHD comes alongside a lot of restlessness, irritability, or trouble settling. Those uses are real, but the central approved purpose is ADHD.
How it works
Guanfacine is not a stimulant. It is an alpha-2 adrenergic agonist, which means it acts on a particular set of receptors in the brain. Nerve cells communicate using chemical messengers, and these receptors respond to norepinephrine, one of those messengers. The receptors guanfacine acts on sit in the prefrontal cortex, a part of the brain involved in attention, working memory, and impulse control. Acting on them appears to strengthen the signaling in those circuits, which is thought to be how guanfacine helps with ADHD.
This is a different route from a stimulant, which works mainly by raising dopamine and norepinephrine activity more broadly. Guanfacine works more quietly and more gradually. How that translates into day-to-day improvement isn't fully understood, and it's worth being honest about that. What is clear is that the effect builds with steady daily use rather than arriving with a single dose.
Because it is not a stimulant, guanfacine is not a controlled substance and has no potential for misuse. That is one of the main practical differences between it and stimulant ADHD medications.
What to expect
Guanfacine works differently from a stimulant, so the shape of the first weeks is different too. It helps to know that pattern in advance, because the early sedation tends to arrive before the benefit does.
The first one to two weeks
A stimulant works the day you take it. Guanfacine does not. In the first week or two, the most noticeable effect is usually drowsiness rather than any change in attention. Sedation is often strongest early on, and it can feel like more than expected. Prescribers usually start at a low dose and raise it slowly, which softens that early drowsiness and gives blood pressure and heart rate time to adjust. Feeling little change in focus at this stage is normal and is not a sign the medication is failing.
Common side effects
Most people get some side effects, especially early on. The common ones include:
- Drowsiness and sedation, which are common early in treatment.
- Tiredness.
- Dizziness.
- Dry mouth.
- Headache.
- Lower blood pressure.
- Constipation.
- Irritability.
Sedation is the side effect people notice most, and it is often strongest in the first weeks before easing somewhat. If a side effect is severe, or it isn't easing after a few weeks, that is a conversation to have with the prescriber rather than a reason to stop on your own.
Serious side effects and warnings
Serious problems are uncommon, but a few are worth knowing.
- Rebound high blood pressure if stopped abruptly. This is the most important caution. After regular use, stopping guanfacine suddenly can cause blood pressure to climb sharply, sometimes higher than it was before treatment, along with headache and a racing heartbeat. Guanfacine should always be tapered, never stopped all at once. Any plan to stop should go through a prescriber. The same caution applies if several doses in a row are missed.
- Low blood pressure and fainting. Guanfacine lowers blood pressure, and it can cause dizziness or lightheadedness, especially when standing up quickly. In some cases this can lead to fainting. The risk is higher early in treatment, after a dose increase, and when guanfacine is combined with other medications that lower blood pressure. Standing up slowly helps.
- Slowed heart rate. Guanfacine can slow the heart rate. A prescriber will monitor heart rate and blood pressure, particularly when starting the medication or changing the dose.
- Sedation. The drowsiness can be significant, which matters for school, work, and driving. It is worth knowing how guanfacine affects you before driving or doing anything that needs full alertness, and the effect can be stronger if guanfacine is combined with other sedating medications or with alcohol.
Sexual side effects
Guanfacine is not a notable cause of sexual side effects. This is one area where it differs from some other psychiatric medications. If you do notice a change, it is still worth raising with your prescriber.
Weight, appetite, and sleep
Guanfacine is not a major cause of weight change. This is one difference from stimulant ADHD medications, which often reduce appetite and can slow weight gain in children.
It is sedating. That sedation is sometimes useful when ADHD comes with difficulty settling at night, and a prescriber may take it into account when deciding on timing. For some people the drowsiness is a drawback during the day rather than a help at night, and the timing of the dose is one of the things a prescriber can adjust.
Starting and dosing basics
This section is general background, not a dosing instruction for any individual. The right dose is a decision for a prescriber.
Guanfacine for ADHD comes as extended-release tablets. They are taken once daily and swallowed whole, not crushed or chewed, because breaking the tablet would release the medication too fast. Guanfacine is started at a low dose and increased gradually, which keeps early sedation and blood pressure changes manageable. It should not be taken with a high-fat meal, because that can raise its levels in the body.
One point matters more here than people often realize. Immediate-release guanfacine, the older blood pressure form, and extended-release guanfacine, the ADHD form, are not interchangeable dose for dose. The two forms release the medication at different rates and reach different levels in the body, so a milligram of one is not equal to a milligram of the other. Switching between them is not a simple swap, and it is something only a prescriber should manage.
Missed doses and interactions
If you miss a dose, the general guidance is to take it when you remember, unless it is almost time for the next dose. In that case, skip the missed dose and carry on. Don't take two doses to make up for one. If you miss several doses in a row, do not simply restart at the same dose, and don't stop guanfacine abruptly. Check with your prescriber, because restarting may need to be done gradually and stopping abruptly can raise blood pressure.
Several interactions matter. Guanfacine is processed in the liver mainly by an enzyme called CYP3A4, and other medications can speed that enzyme up or slow it down.
- Strong CYP3A4 inhibitors slow the breakdown of guanfacine, which can raise its levels and increase sedation and blood pressure effects. Some antifungal medications, certain antibiotics, and grapefruit juice fall into this group. A prescriber may lower the guanfacine dose when one of these is added.
- Strong CYP3A4 inducers speed the breakdown of guanfacine, which can lower its levels and reduce how well it works. Some seizure medications and the antibiotic rifampin are examples. A prescriber may need to adjust the dose in the other direction.
Other interactions matter too. Other blood pressure medications can add to the blood pressure lowering effect and the risk of fainting. Other sedating medications, and alcohol, can add to the drowsiness. Give every prescriber and pharmacist a full list of your medications and supplements, including over-the-counter ones, so these interactions can be checked.
Stopping and tapering
Guanfacine should be tapered, not stopped suddenly. Stopping abruptly after regular use can cause a rebound rise in blood pressure, sometimes above where it started, along with headache and a fast heartbeat. A prescriber can plan a gradual step-down, often reducing the dose in stages over a week or more, so the dose comes off safely. Even if you feel ready to stop, it is worth doing slowly and with guidance. This caution is about blood pressure, not about addiction. Guanfacine is not a controlled substance and does not cause dependence.
Pregnancy and breastfeeding
This is an area where individual circumstances matter and the decision belongs with a clinician. There is limited information on guanfacine in pregnancy and breastfeeding. ADHD itself affects daily functioning, and that is part of what a clinician weighs. None of that adds up to one answer that fits everyone. Anyone who is pregnant, planning a pregnancy, or breastfeeding should talk it through with their prescriber so the specific risks and benefits can be weighed for their situation.
Cost and generic availability
Guanfacine is available as a generic, and the extended-release generic has been on the market for years. Intuniv is a brand name for the extended-release form. The brand and the generic contain the same active medication and work the same way.
There are two separate guanfacine products to keep clear when thinking about cost. Immediate-release guanfacine, the older blood pressure version, is widely available as a low-cost generic. Extended-release guanfacine, the ADHD version, is also available as a generic and is generally affordable, though it has typically cost more than the immediate-release form. Coverage and price still vary by insurance plan and pharmacy, and the brand-name Intuniv usually costs more than the generic without offering any added benefit, so asking the pharmacist about the generic price is worthwhile.
Common questions
Is guanfacine a stimulant? No. Guanfacine is a non-stimulant. It works through a different mechanism and tends to be calming rather than activating.
Is it addictive? No. Guanfacine is not a controlled substance and has no potential for misuse. It still should not be stopped abruptly, for blood pressure reasons rather than addiction.
How long until it works? It is not fast-acting. It takes a few weeks of regular daily use to reach its full effect.
Can it be used with a stimulant? Yes. Guanfacine is often added to a stimulant, where it can help with hyperactivity and impulsivity. This is a common way it is used.
Why can't it be stopped suddenly? Stopping abruptly after regular use can cause a rebound rise in blood pressure. Guanfacine should be tapered with a prescriber instead.
Are the immediate-release and extended-release forms the same? No. They release the medication at different rates and are not interchangeable dose for dose. Switching between them is something a prescriber should manage.
Questions to ask your prescriber
- What are we hoping this treats, and how will we know it's working?
- Should I expect to take this on its own or alongside a stimulant?
- How will my blood pressure and heart rate be monitored?
- What should I do if the drowsiness affects school, work, or driving?
- Are any of my other medications likely to interact with guanfacine?
- If we decide to stop it later, how would we taper it safely?
Sources
This guide draws on current prescribing information and public health references. It is reviewed for clinical accuracy and updated as guidance changes.
Define this drug class in the network glossary Non-stimulant ADHD medication on Shrinktionary
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- MEDICATION Guanfacine (Intuniv) (current)
- CLASS ADHD medications
- CONDITION ADHD (on Shrinkopedia)
- MAP Skill building on Unstuck
- CARE ADHD care at shrinkMD
The Knowledge Path is a curated walk. Every step is one decision away from the next.
When to seek urgent help
Most side effects are mild, but a few problems are urgent and need same-day attention.
- Severe allergic reactions, such as swelling of the face, lips, or tongue, or trouble breathing.
- Fainting, a very slow or very fast heartbeat, or chest pain.
- New or worsening thoughts of suicide or self-harm.
Managing a medication needs a prescriber
Any psychiatric medication has to be started and adjusted by a clinician who can follow you over time. If you don't have a prescriber, our guides section explains the options, including in-person care and telepsychiatry, and how to choose between them.