Clonidine is a prescription medication used to treat attention deficit hyperactivity disorder (ADHD). It’s available in a variety of forms as both a generic and brand-name drug. But, it may cause side effects.
Clonidine is a prescription medication. It’s available as a patch, an oral tablet, and an oral extended-release tablet.
Clonidine extended-release tablets are available as the brand-name drug Kapvay. They’re also available as a generic drug. Generic drugs usually cost less. In some cases, they may not be available in every strength or form as the brand.
Clonidine extended-release tablets are used to treat symptoms of attention deficit hyperactivity disorder (ADHD). They can be used by people aged 6–18 years.
This drug may be used as part of a combination therapy. That means you may need to take it with other drugs.
Clonidine belongs to a class of drugs called centrally acting alpha-agonists. It isn’t known exactly how clonidine extended-release tablets work to reduce symptoms of ADHD. We do know that clonidine works in the part of the brain that helps regulate behavior, attention, and how we express emotion.
- Allergy Warning: Don’t take oral clonidine if you’ve ever had an allergic reaction to clonidine or the clonidine patch. Taking oral clonidine after having a skin reaction to the patch can cause a rash over your whole body, itching, and possibly a severe allergic reaction.
- Surgery Warning: You can take clonidine up to 4 hours before a surgery. Don’t take it within the 4 hours right before your surgery. You can restart it right away after surgery.
Clonidine oral tablet can cause drowsiness. However, this effect might go away the longer you take it. It can also cause other side effects.
More common side effects
Mild side effects may go away within a few days or a couple of weeks. Talk to your doctor or pharmacist if they’re more severe or don’t go away. The more common side effects that can occur with clonidine include:
- dry mouth and dry eyes
- stomach upset or pain
- upper respiratory tract infection
- feeling irritable
- trouble sleeping
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 911. Serious side effects can include:
- increased then decreased blood pressure
- slower or faster heart rate
- uneven heart rate
- dizziness when you stand
- passing out
- slowed breathing or trouble breathing
- chest pain
- hallucinating (seeing things that aren’t there)
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.
Clonidine oral tablet 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 have questions 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.
Drugs that increase drowsiness
Don’t combine these drugs with clonidine. Taking these drugs with clonidine might increase drowsiness:
- barbiturates such as:
- phenothiazines such as:
- benzodiazepines such as:
- drugs for pain (opioids) such as:
- other sedating drugs
Tricyclic antidepressants (TCA)
Combining these drugs with clonidine can increase your blood pressure. Examples of these drugs include:
- clomipramine (Anafranil)
- desipramine (Norpramin)
- doxepin (Sinequan)
- imipramine (Tofranil)
- nortriptyline (Pamelor)
- protriptyline (Vivactil)
- trimipramine (Surmontil)
Combining these heart drugs with clonidine can slow your heart rate. This can become severe. You may need to go to the hospital or have a pacemaker. If you’re taking one of these medications, clonidine may not be the best choice for you.
Examples of these heart drugs include:
- beta blockers
- calcium channel blockers such as:
If you take these drugs with clonidine, you may get dizzy or have trouble balancing when you sit after lying down, or stand after sitting. This is called orthostatic hypotension. Examples of these drugs include:
- clozapine (Clozaril)
- aripiprazole (Abilify)
- quetiapine (Seroquel)
Blood pressure drugs
Combining these drugs with clonidine may lower your blood pressure too much. This raises your risk of passing out. Examples of these drugs include:
- angiotensin II receptor blockers such as:
- angiotensin-converting enzyme (ACE) inhibitors such as:
- diuretics such as:
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.
This drug comes with several warnings.
Don’t use this medication if you’ve had an allergic reaction to clonidine tablets or parts of the clonidine patch in the past.
Taking oral clonidine after having a skin reaction to the clonidine patch can cause a rash over your whole body, itching, and possibly a severe allergic reaction.
A severe allergic reaction may cause:
- trouble breathing
- swelling of your throat or tongue
Combining alcohol with clonidine may cause a dangerous sedative effect. It may slow your reflexes, cause poor judgment, and cause sleepiness.
Warnings for certain groups
For people with heart problems: This includes low blood pressure, low heart rate, and heart disease. This medication decreases blood pressure and heart rate. You may be at risk for more serious side effects if you already have low blood pressure or a low heart rate.
For people who get dizzy when standing: This condition is called orthostatic hypotension. Clonidine can make this condition worse. Don’t stand up too quickly and make sure not to get dehydrated. These can increase your dizziness and risk of fainting.
For people with syncope (fainting): Clonidine can make this condition worse. Don’t stand up too quickly and make sure not to get dehydrated. These can increase your dizziness and risk of fainting.
For people with eye problems: This includes dry eye syndrome and problems focusing your eyes. Clonidine may make these problems worse.
For pregnant women: Clonidine is a category C pregnancy drug. That means two things:
- Research in animals has shown adverse effects to the fetus when the mother takes the drug.
- There haven’t been enough studies done in humans to be certain how the drug might affect the fetus.
Speak with your doctor if you’re pregnant or plan to become pregnant. Clonidine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
For women who are breastfeeding: Clonidine may pass into your breast milk and can cause side effects in a breastfeeding child. Tell your doctor if you’re breastfeeding. You may need to decide whether to stop breastfeeding or stop taking clonidine.
For seniors: This medication affects blood pressure, which may cause dizziness and increase your risk of falling.
For children: This drug hasn’t been studied in children with ADHD under the age of 6 years.
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
Form and strength
Form: oral extended-release tablet
Strengths: 0.1 mg
Dosage for attention deficit hyperactivity disorder (ADHD)
Adult dosage (ages 18 years and older)
A safe and effective dose hasn’t been established for adults.
Child dosage (ages 6–17 years)
- The starting dose is 0.1 mg taken at bedtime.
- Doses may be increased by an additional 0.1 mg per day every week until your symptoms are better or you get to the daily maximum.
- Total daily doses are 0.1–0.4 mg per day.
- The total daily dose is divided into 2 doses taken twice per day.
- If you’re stopping clonidine, the total daily dose should be decreased by 0.1 mg every 3–7 days.
Child dosage (ages 0–5 years)
A safe and effective dose hasn’t been established for this age group.
Special dosage considerations
If you have kidney disease: If you have kidney disease, your starting dosage may be lower. Your dosage may be increased based on your blood pressure.
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 speak with your doctor or pharmacist about dosages that are right for you.
Clonidine is a long-term medication. It comes with serious risks if you don’t take it as prescribed.
If you don’t take it at all or not on schedule
Your signs and symptoms of ADHD may get worse.
If you stop suddenly
It’s important not to abruptly stop taking this drug. This can lead to a withdrawal reaction. Side effects may include:
- rapid increase in blood pressure
What to do if you miss a dose
If you miss a dose, skip the missed dose and take the next dose as scheduled.
Don’t take more than the prescribed total daily amount of clonidine in a 24-hour period.
How to tell if the drug is working
You may be able to tell this drug is working if you notice improvement in your symptoms, especially attention, hyperactivity, and impulsivity.
Keep these considerations in mind if your doctor prescribes clonidine for you.
- You can take clonidine with or without food.
- Take clonidine in the morning and at bedtime: The total daily dose is split into 2 doses. Each dose is usually the same, but sometimes a higher dose is needed. If you have a higher dose, take it at bedtime.
- Don’t crush, chew, or cut this medication.
- Store this drug at room temperature between 68°F and 77°F (20°F and 25°C).
- Keep the medication away from light.
- Keep this drug away from areas where it could get wet, such as bathrooms.
A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.
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 drug.
- You may need to show your pharmacy’s preprinted label to identify the medication. Keep the original prescription-labeled box with you when traveling.
Your doctor may do tests during your treatment with this drug. These tests can help make sure the drug is working and that you’re staying safe during therapy. Your doctor may:
- check your kidney function to see if your starting dose needs to be lower.
- do an electrocardiogram or other heart tests to check how your heart is working and to make sure you aren’t having side effects.
- monitor your blood pressure and heart rate to make sure this drug is working.
The cost of these tests will depend on your insurance coverage.
Many insurance companies require a prior authorization for the brand-name version of this drug. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.
There are other medications available to treat your condition. Some may be more suitable for you than others. Talk to your doctor about possible alternatives.
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.