Can you get guanfacine over the counter?

Reviewed by:
Dr. Robert Kwok
Director of Health Informatics
Last updated on December 14, 2021

If you’ve been diagnosed with high blood pressure or ADHD, you may be thinking about taking ganfacine. What is ganfacine? And do you need a prescription to get it? Keep reading to find out all this and more.

Is guanfacine available over the counter?


By law, you have to have an appointment with a doctor who can independently determine that you need guanfacine for your condition.

The good news is, HealthTap can help with that! You can schedule an appointment with your doctor online. They can help diagnose you and, if necessary, write you an online prescription that’s sent to your local pharmacy.

What is guanfacine and what does it do?

There are two main types of guanfacine:

  1. Tablets under the brand name Tenex are used to treat high blood pressure.

  2. Long-acting tablets under the brand name Intuniv are used to treat attention deficit hyperactivity disorder (ADHD).

Obviously, high blood pressure/hypertension and ADHD are two completely different conditions. Guanfacine can be used to treat both, and is usually combined with other medications and therapies when used to treat ADHD.

How does it work?

With high blood pressure, guanfacine controls certain nerve impulses and as a result, relaxes blood vessels and reduces blood pressure.

When guanfacine is used to treat ADHD—most often in children and teens—it increases attention and decreases restlessness. 

What’s the right dosage for guanfacine?

The dosage is unique for each person and your doctor will tell you what the right amount is for you. Always take prescription medication according to what your doctor tells you.

Generally speaking, you can expect your recommended guanfacine dosage to fall somewhere in this range:

  • Tablets for high blood pressure: 1 milligram (mg), once per day when you go to bed.

  • Extended-dose tablets for ADHD: 1 mg, once per day for anyone 6 and up, and usually never more than 4 mg per day.

You should never take double doses, and if you miss a dose for two or more days in a row, you should check in with your doctor to find out what to do.

Side effects of guanfacine

When guanfacine is working well for you, you’ll notice that your blood pressure is lower, or, if you’re taking it for ADHD, that you’re more focused and less distractible. You may also experience sharper memory and better impulse control.

However, you may also have less pleasant side effects like:

  • Dizziness.

  • Drowsiness.

  • Headache.

  • Depression.

  • Constipation.

  • Gas pains.

  • Diarrhea.

  • Loss of appetite.

  • Fatigue.

  • Nasal congestion.

Rare side effects could include:

  • Chest pain.

  • Shortness of breath.

  • Skin rash.

  • Swelling of the hands or feet.

  • Blurred vision.

  • Yellowing of the eyes or skin.

Lastly, cardiovascular side effects could include orthostatic hypotension, dizziness, and palpitations.

Precautions to take

Guanfacine is generally a safe and effective drug for the treatment of high blood pressure and ADHD. But it does require diligence on your part and your doctor’s. Here are some things to keep and eye on.

  • See your doctor regularly to make sure the medication is working and that you should continue taking it.

  • Measure your heart rate before and while taking guanfacine. If you’re ever outside the range your doctor recommends, call them immediately.

  • Don’t stop taking guanfacine suddenly, as it could cause an unsafe increase in blood pressure.

  • If you’re having surgery, tell the doctor performing the procedure that you’re taking guanfacine (including dental surgery).

  • Check with your doctor before you use alcohol or CNS depressants—guanfacine will increase the effects of these substances.

  • Don’t drive or operate heavy machinery until you know how the medicine affects you.

  • Check with your doctor or dentist if dry mouth persists for more than two weeks. Long-term dryness can increase the risk of dental disease.

  • Check with your doctor before you take any other medications, including over-the-counter medicine and herbal supplements. 

Common questions

Does guanfacine cause weight gain or weight loss?

It can cause weight gain. Weight loss is less common, but some people experience loss of appetite, and over time, that could lead to weight loss.

If you experience either, talk to your doctor.

Does guanfacine stunt your growth?

No, there’s no proven study to suggest guanfacine affects growth for children who take it.

Can guanfacine be crushed?

Do not do this. 

Guanfacine, like many prescription medications, is designed in tablet form so that it releases into your body gradually. Never take any medication except as directed by your doctor.

Can you overdose on guanfacine?

Yes. If you experience extreme dizziness, tiredness, or weakness, call 911 immediately.

Can guanfacine cause insomnia?

Drowsiness is more likely, but guanfacine can cause sleeplessness in some cases.

Can you take other drugs with guanfacine?

Not without checking with your doctor first. This includes over-the-counter medications and herbal supplements.

Can I eat normal foods while taking guanfacine?

Talk to your doctor about this. 

If you have high blood pressure, your doctor may recommend dietary changes in conjunction with taking guanfacine to treat your condition. Additionally, you should check with your doctor before you consume alcohol, since guanfacine can enhance its effects.

For children taking guanfacine for ADHD, doctors often recommend avoiding foods that are high in fat.

Can guanfacine cure ADHD?

No, but it can help. Guanfacine is usually used in combination with other therapies and/or drugs for the treatment of ADHD.

If you have any quesiton about getting a prescription, consult your online doctor at HealthTap.

HealthTap Editors

HealthTap Editors

HealthTap articles are reviewed by MDs, PhDs, NPs, nutritionists and other healthcare professionals. Visit to learn more and meet some of the medical editorial board members behind our blog. The information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. HealthTap is a virtual-first, affordable urgent- and primary-care clinic, providing top-quality physician care nationwide to Americans with or without insurance. Our proprietary, easy-to-use, and innovative apps and electronic medical record apply Silicon Valley standards to effectively engage consumers and doctors online to increase the equity, accessibility, and efficiency of ongoing medical care for consumers, providers, employers, and payers. In addition, with HealthTap, businesses can offer virtual primary care to employees for less than the cost of free coffee. HealthTap's US-based board-certified physicians are available throughout North America. For more information, visit

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