Guanfacine (Tenex/Intuniv)

What guanfacine is

Guanfacine is a medication sold under the brand names Tenex and Intuniv. It works as an alpha-2 agonist, which means it calms the nervous-system signals that drive arousal and raise blood pressure. It started as a blood pressure medicine, and that same settling effect is why it is used for attention. It is not a stimulant and not a controlled substance. Tenex is an immediate-release form used mainly for blood pressure, and Intuniv is an extended-release form used for ADHD.

What it treats

In mental health, your clinician might suggest guanfacine for:

• Attention-deficit/hyperactivity disorder (ADHD)

Guanfacine is also approved for high blood pressure. Beyond those approved uses, it is sometimes used off-label for tics. Whether it is a good fit depends on several factors, including your blood pressure, your history, and your other medications. As with everything in psychiatry, that is decided case by case.

How it works

Honestly, no one knows with complete certainty how guanfacine produces its benefit. What robust research supports is that it calms an overactive part of the nervous system, which can steady attention and lower blood pressure. The biology is only part of the picture: how much a medication helps, and how it feels, is individual. Two people on the same medication can have very different experiences.

How to take it

There is no single right way to take guanfacine; it depends on you and your clinician, and the extended-release form is not interchangeable with the immediate-release one. The plan you and your clinician make together is the one to follow, not a number you read online. A few points matter here:

• Take it the way you and your clinician agreed, and do not increase the amount on your own.
• If you are on the extended-release form, swallow it whole and do not crush or chew it, and avoid taking it with a high-fat meal unless your clinician says otherwise.
• Do not stop it suddenly. Stopping abruptly can cause a significant rebound in blood pressure, so when the time comes your clinician can lower it gradually in a way that is much safer.
• Because it can make you drowsy or lightheaded, be careful with driving or standing up quickly until you know how it affects you.
• If you miss a dose, ask your clinician or pharmacist what to do rather than doubling up.

What to expect

This varies from person to person. Drowsiness is common in the first days and often eases as your body settles. How much it helps, and how soon, depends on what you are using it for and on you. The right plan may change over time, and that is something you and your clinician revisit together. If it does not turn out to be the right fit, that is useful information, not a dead end, and there are other options. As always, this is case by case.

Side effects

Not everyone gets side effects, and many that do happen ease as your body settles. The lists below are possibilities, not certainties.

Possible more common side effects:

• Drowsiness, sleepiness, or tiredness
• Dry mouth
• Dizziness or lightheadedness, especially when standing up
• Lower blood pressure
• Constipation
• Headache or feeling irritable

If any of these stick around or bother you, send a non-urgent message through the patient portal or bring it up at your next visit; often a small change helps.

Less common, but concerning side effects that could require emergency care:

• Fainting, a very slow heartbeat, or severe dizziness
• A significant rise in blood pressure if the medicine is stopped suddenly, with severe headache, a racing heart, or anxiety
• New or worsening low mood or changes in behavior
• Signs of an allergic reaction: rash, hives, or swelling of the face, lips, or throat
• Any new or worsening thoughts of harming yourself

For any of these, use the help options at the top of this page: call 911 or go to the nearest emergency department for a medical emergency or severe reaction, or call or text 988 for a mental health crisis.

When to reach out, and where

For routine questions, side effects that can wait, or how things are going, send your clinician a message through the patient portal. These are part of your ongoing care and are answered in the normal course of a few business days, so they are best for things that are not urgent.

If something feels urgent, you do not need to wait for a reply. The help options at the top of this page are the fastest way to get care: 911 or the nearest emergency department for a medical emergency or severe reaction, or 988 any time for a mental health crisis or thoughts of self-harm.

Questions to ask your clinician

• What are you hoping guanfacine will help with in my case?
• How and when will we know if it is working?
• What should I watch for with my blood pressure?
• Which form is right for me, and why?
• What is the plan if this one turns out not to be the right fit?
• How will we handle stopping it, if and when we get there?