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Clonidine (Catapres®, Dixarit®)

Summary: Clonidine (Catapres®, Dixarit® and generic forms) belongs to a group of medications called “alpha2-agonists”. It is approved by Health Canada to treat high blood pressure in adults. In children and adolescents, this medication may part of the treatment of attention deficit/hyperactivity disorder (AD/HD), tic disorders (such as Tourette syndrome) and sleep problems.
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What is clonidine used for?

Clonidine may be used for different conditions:  

  • Impulsivity that is seen withAD/HD
  • Tic disorders (e.g. shrugging, blinking, head turning, muscle twitches, and throat clearing)
  • Sleep difficulties
  • Anxiety disorders
  • Smoking cessation (nicotine withdrawal)

There may also be other reasons why your doctor is prescribing this medication . If you are unclear why this medication is being prescribed, please ask your doctor.

How does clonidine work?

Clonidine works by affecting the activity of the brain chemical (neurotransmitter) called norepinephrine. Norepinephrine normally influences blood pressure, heart rate and anxiety in the body, but it also affects attention and arousal. This medication stabilizes certain areas of the brain, making them “less excited”. This in turn improves symptoms of AD/HD, anxiety, sleep difficulties, nicotine withdrawal, and tic disorders.

Clonidine in children and adolescents

In the United States, a long-acting form of clonidine has been approved for treating AD/HD in children and adolescents.


However in Canada, like many medications used to treat childhood disorders, Clonidine is not officially approved by Health Canada for use in children and adolescents.


Nonetheless, when the potential benefits (e.g., reducing your symptoms) of using Clonidine outweigh the potential risks (e.g., the side effects), many doctors may prescribe it “off-label” to treat several conditions.


Clonidine does not cure AD/HD. This medication aims to improve functioning by moderately reducing AD/HD symptoms such as hyperactivity, impulsive behaviour. It can also help people with ADHD tolerate frustration better. In comparison, clonidine may be less beneficial for improving attention and concentration. Despite this, clonidine remains an important treatment option for AD/HD patients who have undesirable side effects from, or do not respond to stimulant medications.


Whenever possible, adding behavioral management strategies (for example: rewarding good behaviour, teaching problem-solving techniques) to clonidine increases the chance for benefit.

How should clonidine be taken?

Clonidine is available as tablets that are taken by mouth. For treatment of AD/HD and tic disorders, it is usually taken two to four times per day. To help with sleep difficulties, it is usually taken once daily two hours before bedtime. It may be taken with or without food. Your doctor will determine how much you should take, according to your body weight and your response to this medication. When starting treatment with clonidine, your doctor may start with a lower dose and then slowly increase the dose over a few weeks, until the ideal dose is reached or side effects occur.


Clonidine needs to be taken regularly on a daily basis to be effective. Treatment with clonidine should not be stopped suddenly, since this could lead to an undesirable rapid increase in blood pressure. You should take this medication at the same time(s) everyday for best effects.

When will clonidine start working?

Clonidine needs to be taken for two weeks before you see an improvement in your symptoms. It may take 2 to 4 months to see the full benefits of the medication. Effects such as drowsiness and sedation (sometimes considered desirable) may appear sooner (even after the first dose). Unless directed by your doctor, do not increase, decrease, or stop taking the medication if there are no improvements in the first few weeks. A delay in response is normal.


Medications like clonidine do not work for everyone. If you are not feeling better within several weeks, your doctor may recommend switching you to a different medication.

How long do I have to take clonidine?

This depends on the symptoms you have, how frequently they occur, and how long you have had them. Different people take clonidine for different lengths of time. Whether or not you need medication should be reevaluated from time to time. Some people only require this medication during particular times of their life such as when they are in school, whereas some people continue to benefit from medication for many years. It may be dangerous to suddenly stop taking clonidine after you have been taking it on a regular basis. If you and your doctor decide to stop using clonidine, your doctor will explain how to safely lower the dose gradually to prevent a rapid increase in blood pressure and other undesirable effects as your body adjusts to being without it. Do not stop taking this medication suddenly without first discussing it with your doctor.

Is clonidine addictive?

No, clonidine is not addictive and you will not have “cravings” for it like some people do with nicotine or street drugs. In general, people with AD/HD may be at an increased risk to abuse substances over the long run. By effectively treating AD/HD, patients may be less likely to abuse substances than those who do not take medications to help manage AD/HD.

What are the side effects of clonidine and what should I do if I get them?

As with most medications, side effects may occur when taking clonidine. Most side effects are mild and temporary. Sometimes the side effects may occur before any of the beneficial effects. It is also possible to experience side effects that they feel are concerning or long-lasting. If this occurs, speak to your doctor about ways to manage them. On the next page are some of the more common side effects of taking this medicine. In brackets are suggested ways to lessen these effects.


Common side effects


Side effects are usually more common when starting a medication or after a dose increase. If any of these side effects is troublesome for you, please discuss them with your doctor, nurse or pharmacist.

  • Drowsiness (try taking the dose at bedtime. Do not drive or operate machinery until you know how this medication affects you. If daytime clonidine doses make you drowsy, talk with your doctor.)
  • Dry mouth (try chewing sugarless gum or sucking hard sugar-free candies, ice chips, or popsicles)
  • Dry eyes (try using artificial tears eye drops)
  • Dizziness, lightheadedness or low blood pressure (try getting up slowly from a sitting or lying down position. If it becomes severe (for example: falling or fainting), seek medical help immediately)
  • Headache (try using a pain reliever like acetaminophen (Tylenol®). If your headache comes on suddenly and is extremely intense, seek emergency help immediately)
  • Constipation (try drinking more fluids, exercising, or increasing the amount of fiber in your diet)
  • Stomach upset, nausea, vomiting (try taking the medication following a meal)

There are risks involved with taking any medication. Make sure you have had a conversation with your doctor about the potentially serious effects of clonidine.


Contact your doctor IMMEDIATELY if you have any of these potentially serious side effects:

  • Skin rash with swelling and itching or trouble breathing (seek emergency help immediately)
  • Worsened depression (prolonged sadness) or other unusual changes in mood (discuss this with your doctor)
  • Fast or slow heart rate, irregular heart beat (discuss this with your doctor)
  • Increased agitation, restlessness or irritability
  • Sudden onset of high blood pressure, fast heart beat, agitation, headache, stomach upset, sweating, nausea or vomiting (This may happen if clonidine treatment is stopped suddenly. If these effects occur, seek emergency help immediately)

What precautions should my doctor and I be aware of when taking clonidine?

Several medications can interact with clonidine, including high blood pressure medications; some cough and cold medications; anti-histamines such as diphenhydramine (Benadryl®); some antidepressants such as nortriptyline (Aventyl®); some medications used for sleep, anxiety, seizures, or other psychiatric disorders; and several others. If you are (or begin) taking any other prescription or over-the-counter medications, be sure to check with your doctor or pharmacist to see if they are safe to use. Your doctor may need to change the doses of your medication(s) or monitor you carefully for side effects if you are taking medications that interact with clonidine.


Tell your doctor of pharmacist if you:

  • have any allergies or have experienced a reaction to a medication.
  • have diabetes or kidney disease
  • have heart conditions or a family history of early heart disease or sudden death
  • have psychiatric conditions such as depression or bipolar disorder
  • have Raynaud’s disease (a circulation disorder with discoloration of fingers, toes or other areas)
  • miss a period, are pregnant (or are planning to become pregnant) or are breast-feeding. Tell your doctor if you become pregnant while taking clonidine
  • are currently using alcohol or street drugs, as these substances can decrease how well clonidine works for you and/or make you feel drowsy

What special instructions should I follow while taking clonidine?

  • Keep all appointments with your doctor and the laboratory. Your doctor may order certain assessments and tests (for example: reports from teachers, AD/HD rating scales, heart rate, blood pressure) to check how you are responding to clonidine and to monitor for side effects.
  • Do not allow anyone else to use your medication.

What should I do if I forget to take a dose of clonidine?

  • If you take clonidine regularly and you forget to take it, take it as soon as you remember.
  • If it is more than 4 hours after your regularly scheduled dose, skip the missed dose and continue with your regular schedule. Do NOT double your next dose.

What storage conditions are needed for clonidine?

  • Keep this medication in the original container, stored at room temperature away from moisture and heat (e.g., not in the bathroom or kitchen)
  • Keep this medication out of reach and sight of children.

Share with family

You may wish to share this information with your family members to help them to understand your treatment options. Since every person's needs are different, it is important that you follow the advice provided to you by your own doctor, nurse and/or pharmacist and speak to them if you have any questions about this medication.

About this document

Special thanks to the Kelty Centre for Mental Health for permission to adapt this document. The original document was developed by health professionals of BC Mental Health and Addiction Services, and reviewed by the staff of the Kelty Mental Health Centre. French translation provided courtesy of the Ontario Centre of Excellence for Child and Youth Mental Health and the Children's Hospital of Eastern Ontario (CHEO).

Creative Commons license

You are free to copy and distribute this material unchanged and in its entirety as long as 1) this material is not used in any way that suggests we endorse you or your use of the material, 2) this material is not used for commercial purposes (non-commercial), 3) this material is not altered in any way (no derivative works). View full license at For any other uses, please contact the original rights holder, the Kelty Mental Health Centre.


Information in this pamphlet is offered ‘as is' and is meant only to provide general information that supplements, but does not replace the information from your health provider. Always contact a qualified health professional for further information in your specific situation or circumstance.


Date Posted: Jun 14, 2013
Date of Last Revision: Oct 8, 2016

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