Clonidine: Uses, Side Effects, Dosage, Mechanism of Action, Interactions and Presentations

It is a medication used to treat high blood pressure and attention deficit hyperactivity disorder.

Clonidine (generic or commercial names Catapres, Kapvay, Nexiclon, Clophelin, and others) is also used for anxiety disorders, tic disorders, abstinence (alcohol, opioids, or smoking), migraine, redness of menopause, diarrhea, and certain pain conditions.

It is classified as a centrally acting α2-adrenergic agonist and an imidazoline receptor agonist that has been in clinical use since 1966.

According to the National Institutes of Health and other sources, it is not uncommon for doctors to prescribe Clonidine to treat other conditions, including:

  • Painful menstrual periods.
  • Tourette’s syndrome.
  • Hot flashes or menopause hot flashes.
  • Leave the cigarette.
  • Detoxification, addiction to narcotics.
  • Abuse of alcohol or alcoholism.
  • Restless Leg Syndrome.
  • Diabetes.

Administering Clonidine to children before surgery may help relieve pain after an operation.

However, the potential use of Clonidine for postoperative pain relief requires further investigation.

What is Clonidine, and how does it work?

Clonidine (Catapres, Catapres-TTS) is an oral and topical medication (applied to the skin) prescribed by a doctor for the treatment of high blood pressure ( hypertension ).


It works by stimulating the receptors in the nerves of the brain that reduce the transmission of messages from the nerves in the brain to the nerves in other areas of the body.

As a result, it decreases the heart rate and reduces blood pressure. The food and drug administration approved Clonidine in September 1974.

Medical uses of Clonidine

Clonidine was introduced in 1966. It was used for the first time as a treatment for hypertension under the trade name of Catapres.

The United States Food and Drug Administration (FDA) has approved Clonidine to treat attention deficit hyperactivity disorder, under Kapvay alone or with stimulants in 2010, for pediatric patients between 6 and 17 years. Then it was approved for adults.

The Therapeutic Goods Administration (Clonidine) is an accepted but not approved use for attention deficit hyperactivity disorder in Australia. The contiguous Clonidine with methylphenidate has been studied for attention deficit hyperactivity disorder medication and treatment.

According to clinical trials presented on the administration of drugs and foods, its effectiveness is comparable to the stimulants commonly used for attention deficit hyperactivity disorder.

Although it is not as effective as methylphenidate in treating attention deficit hyperactivity disorder, Clonidine does offer some benefits; It can also be helpful with stimulant medications.

Some studies show that Clonidine is more sedating than guanfacine, which can be better when lying down with a stimulant in the morning. Clonidine can be used to treat Tourette syndrome (precisely to control or decrease tics).

Clonidine can be used to relieve the withdrawal and containment symptoms associated with the use of long-term narcotics and alcohol, such as benzodiazepines and nicotine (smoking).

It can relieve and improve the signs and symptoms of opioid withdrawal by oppressing the reactions and responses of the sympathetic nervous system, such as tachycardia and hypertension, as well as decreasing sweating, hot flashes, flushing, and general restlessness. It can also help and be useful for smokers to quit smoking.

The effect of sedation is also advantageous. However, its subsequent products may contain insomnia, which worsens an already frequent feature of opiate withdrawal.

Clonidine also has several non-approved uses and has been prescribed to treat psychiatric disorders, including stress, sleep disorders, and hyperactivity caused by post-traumatic stress disorder, borderline personality disorder, and other anxiety disorders.

Clonidine is also a mild sedative and can be used as premedication before surgery. Its epidural use for pain during heart attack, postoperative and intractable pain has also been studied extensively.

Clonidine has also been suggested as a treatment for rare cases of dexmedetomidine withdrawal. Clonidine can be used in restless legs syndrome.

It can also treat facial flushing and redness associated with rosacea. It has also been successfully used topically in a clinical trial to treat diabetic neuropathy.

Clonidine can also be used for migraines and hot flashes associated with menopause. Clonidine has also been used to treat diarrhea associated with irritable bowel syndrome, fecal incontinence, diabetes, diarrhea associated with withdrawal, intestinal insufficiency, neuroendocrine tumors, and cholera.

Use Clonidine with caution if you have a history of heart problems or strokes, and make sure the doctor knows you have had these conditions.

Your doctor will also want to know before you start with Clonidine if you have any of these other conditions:

Catapres and Catapres-TTS are the brands of this medicine available in the US. UU For the management and treatment of high blood pressure. The Jenga brand has been discontinued in the United States.

The generic is available for this medicine in tablet as a tablet in generic form; however, no generic is available for the patch form.

Do I need a prescription or medication order for Clonidine?

Yes, a prescription or medical order from the treating physician or health professional is necessary for this medication. Always tell your doctor if you are allergic to any medicine.

Talk to your doctor about the danger of stopping Clonidine suddenly, especially if you have a surgical procedure nearby.

You will most likely continue taking Clonidine until before surgery and start again shortly after surgery.

What are the approved uses for Clonidine?

Clonidine is approved for the treatment of high blood pressure. It can be used alone or combined with other medications to treat high blood pressure.

Clonidine comes in 0.1, 0.2, and 0.3 milligrams (mg) tablets, and your doctor will try to find the lowest dose of Clonidine that works for you.

Usually, take Clonidine twice a day at approximately the same time. A typical dose schedule for an adult with high blood pressure is 0.1 mg in the morning and before bedtime.

Your doctor can increase your dose by 0.1mg each week until you respond well. A daily dose will end between 0.2mg and 0.6mg in divided doses.

People older than 65 and those with kidney disease may need to take lower doses of Clonidine.

What are the uses not approved by administering foods and medicines for Clonidine?

Uses not approved by the Food and Drug Administration (off label) for this medication include the treatment of:

  • Symptoms of narcotic withdrawal.
  • Nicotine withdrawal.
  • Diabetes.
  • Diabetic neuropathy (damage to the nerves).
  • Hot flashes and hot flashes are associated with menopause.

It can also be used as a supplement to control severe pain related to cancer.

Side effects

The consumption of Clonidine produces a decrease in heart rate, one of the reasons it is so effective in treating high blood pressure. It relaxes an individual’s blood vessels, creating more space for more effortless blood flow.

Clonidine can also interact with the brain section that controls impulsivity, which correlates with attention deficit hyperactivity disorder.

Clonidine may also have a sedative effect on a person in the short term, which could cause difficulties in operating a motor vehicle or other machinery. Mixing Clonidine with other depressants, such as alcohol can be very dangerous due to the potentially potentiated effect of the substance.

Overdose of the drug is possible and can significantly affect the body. Hypertension may appear, and later hypotension. Depression of the central nervous system can also occur, as can respiratory depression.

The main adverse effects of Clonidine are sedation, dry mouth, and hypotension (low blood pressure). The most common side effects are:

  • Fatigue.
  • Lethargy.
  • Drowsiness.
  • Constipation.
  • Dry mouth.
  • Headache.
  • Dizziness.
  • Fatigue.
  • Weakness.

Other side effects include:

  • Cutaneous redness.
  • Itching or urticaria .
  • Impotence.
  • Darkening of the skin.
  • Decrease in sexual desire
  • Ejaculatory dysfunction

Possible serious side effects include:

  • Severe rebound high blood pressure.
  • Low blood pressure
  • Slow heart rate
  • Withdrawal symptoms.
  • Depression .
  • Angioedema.
  • Severe allergic reactions
  • Slow heart rate
  • Fainting.
  • Abnormal cardiac behavior

Long-term effects:

There is a possibility of many long-term adverse effects involving Clonidine’s use. People who take the substance may experience fever, headaches, fatigue, and general weakness. More severe effects on the cardiovascular system are also possible.

These effects may include heart palpitations, congestive heart failure, and atrioventricular block. Such serious consequences can be hazardous and, in some cases, irreversible.

The central nervous system can also be affected by the use of Clonidine. Clonidine can cause anxiety, hallucinations, depression, and sleep disorders. These effects can be severe and dangerous and should be treated by medical professionals in a short time.

Gastrointestinal effects may also arise due to prolonged use of Clonidine. Vomiting and nausea are side effects of Clonidine, as are stomach and abdominal pain. Some users also experience constipation.

Severe rebound hypertension occurs after stopping Clonidine. This reaction is more likely to occur if Clonidine stops suddenly (without a gradual dose reduction).

Symptoms of severe rebound high blood pressure may include:

  • Increased salivation.
  • Nervousness.
  • Headache.
  • Heart palpitations.
  • Agitation.
  • Anxiety.
  • Perspiration.
  • Sickness.
  • Muscle pain.
  • Abdominal pain.

Slowly reducing the dose of this medication for several days will prevent these symptoms.


Clonidine suppresses sympathetic flow resulting in lower blood pressure, but sudden discontinuation may cause rebound hypertension due to a rebound in sympathetic outflow.

Clonidine therapy should be gradually reduced by stopping therapy to prevent rebound effects. The treatment of hypertension by abstinence from Clonidine depends on the severity of the condition.

Reintroduction of Clonidine for mild cases, alpha and beta-blockers for more urgent situations. Beta-blockers should never be used alone to treat clonidine withdrawal since alpha vasoconstriction would continue.

The usual oral dose for adults is 0.1mg – 0.3mg twice a day. The maximum oral ratio is 2.4mg per day.

Topical patches should be applied to an area of ​​hairless skin on the upper arm or torso once every seven days. A different skin area should be used when applying a new topical patch.

Mechanism of action

Clonidine treats high blood pressure by stimulating α2 receptors in the brain, decreasing peripheral vascular resistance, and reducing blood pressure.

It has specificity toward the presynaptic α2 receptors in the vasomotor center in the brainstem. This union decreases presynaptic calcium levels, which inhibits the release of norepinephrine (NE). The net effect is a decrease in sympathetic tone.

It has also been proposed that the antihypertensive effect of Clonidine is due to agonism at the I1 receptor (imidazoline receptor), which mediates the sympathomimetic actions of imidazolines to lower blood pressure.

Its mechanism of action in the treatment of attention deficit hyperactivity disorder increases the noradrenergic tone in the prefrontal cortex directly by binding to postsynaptic α2A adrenergic receptors and indirectly by increasing the norepinephrine entry of the locus coeruleus.


Some medicines can affect the way clonidine works, and Clonidine can involve other drugs you are taking.

It is essential to tell your doctor about all your medications, including over-the-counter, illegal, or recreational medications, herbs or herbal preparations, or dietary or nutritional supplements.

When taking Clonidine and sedatives such as alcohol, barbiturates, and some antidepressants, side effects such as drowsiness can become more severe.

This medicine may increase the sedative effects of other medications that cause sedation. Such drugs include:

  • Narcotic analgesics
  • Barbiturates
  • Sedatives such as alprazolam (Xanax) and clonazepam (Klonopin).
  • Ethanol.

Tricyclic antidepressants, for example, amitriptyline (Elavil, Endep), imipramine (Tofranil), desipramine (Norpramin), and clomipramine (Anafranil), may block the blood pressure lowering effects of Catapres. This could cause blood pressure to rise or increase.

Because this medication can reduce your heart rate, it should be used with caution in people who are receiving any other drug that slows their heart rate, such as beta-blockers, for example:

  • Blood pressure medications are called beta-blockers, such as Atenolol (Tenormin).
  • Metoprolol (Lopressor).
  • Propranolol (Inderal).
  • Medicines indicated for the heart include Digoxin (Digitek, Lanoxicaps, Lanoxin).
  • Diltiazem (Cardizem).
  • Verapamil (Calan Covera HS).

Other types of drugs that interact with Clonidine include:

  • Medications for the heart are called calcium channel blockers, which include amlodipine (Norvasc, in Caduet and Lotrel), diltiazem (Cardizem, Dilacor, Tiazac), and felodipine (Plendil, in Lexxel).
  • Antidepressants, especially tricyclic antidepressants, such as clomipramine (Anafranil), desipramine (Norpramin), and doxepin (Sinequan).
  • Tablets and sleeping pills, like Ambien.
  • Medications to treat anxiety, such as Xanax or Valium.
  • Medications for seizures include phenytoin (Dilantin) and levetiracetam (Keppra).

Clonidine may cause drowsiness, so do not drive or participate in dangerous activities until you know how Clonidine affects you.

The use of sedatives and the intake or intake of alcohol can also increase these side effects of Clonidine.

In addition, your doctor may advise you to follow a low-salt diet to help treat your high blood pressure.

Abnormal heart rhythms can occur with the combination of Clonidine and verapamil.

The concentrations of ciclosporin (Sandimmune, Neoral) in the blood may increase when Clonidine is started. This interaction may cause kidney damage due to elevated ciclosporin levels.

Nonsteroidal anti-inflammatory drugs (NSAIDs), for example, ibuprofen (Motrin, Advil), naproxen (Naprosyn, Aleve), and nabumetone (Relafen) may reduce the antihypertensive effects of Clonidine.

Cocaine, pseudoephedrine, phenylephrine, and phenylpropanolamine can also reverse the blood pressure lowering effects of Clonidine.

According to a 2014 report, Clonidine is often used with narcotic opiates such as methadone, codeine, or heroin.

Clonidine boosts and expands the feeling of being drugged, related to opiates, and reduces the number of psychoactive drugs needed. Clonidine may be easier to acquire than other drugs due to limited awareness of its potential abuse and low cost.

Is Clonidine safe to use during pregnancy or breastfeeding?

There are no adequate studies of this drug during pregnancy. It is excreted in breast milk and could potentially cause adverse effects on the baby.

The Food and Drug Administration classifies Clonidine as pregnancy category C.

On the other hand, it is classified by the Australian Therapeutic Goods Administration as pregnancy category B3, which means that it has shown some detrimental effects on fetal development in animal studies. However, the relevance of this to humans is unknown.

Clonidine may pass into breast milk and may harm a nursing baby; Caution should be exercised in pregnant women who plan to become pregnant or breastfeeding.

What else should I know about Clonidine?

A hypotensive agent derived from imidazoline, Clonidine is a centrally acting α2-adrenergic agonist. It crosses the blood-brain barrier and works on the hypothalamus to induce a decrease in blood pressure.

It can also be administered as an epidural infusion as a complementary treatment in treating severe cancer pain that is not relieved by opioid analgesics alone.

Clonidine can be used for the differential diagnosis of pheochromocytoma in hypertensive patients.

Other uses of Clonidine include:

Prevention of vascular migraine headaches, treatment of severe dysmenorrhea, management of vasomotor symptoms associated with menopause, rapid detoxification in the treatment of opiate withdrawal, treatment of alcohol withdrawal in combination with benzodiazepines

Also, management of nicotine dependence, topical use to reduce intraocular pressure, treatment of open-angle and secondary glaucoma, and hemorrhagic glaucoma associated with hypertension.

Clonidine also shows peripheral activity.

Clonidine suppression test

Clonidine is a prescription drug commonly used to treat high blood pressure.

It is also used in combination with other medications to treat attention deficit hyperactivity disorder, Tourette syndrome, anxiety problems, painful symptoms of menstruation, and abstinence related to addiction.

Clonidine has the potential for addiction or abuse. It is often abused with other drugs, such as methadone, heroin, and prescription painkillers.

The result of Clonidine on the decrease of circulating norepinephrine by a central mechanism was used in the past as a research experiment for pheochromocytoma, which is a tumor synthesizing catecholamines, commonly from the adrenal medulla.

In a clonidine suppression test, plasma catecholamine levels were measured before and 3 hours after the patient had been given an oral test dose of 0.3 mg. An actual test results if there is no deduction in plasma levels.

Clonidine addiction

Addiction to Clonidine is an effect of long-term use of the drug. Symptoms of clonidine addiction include:

  • Uncontrollable use of the substance.
  • Disregard your duties or be less responsible at home and work or school due to Clonidine.
  • An inability to recognize the benefit of Clonidine.
  • Use of Clonidine despite physical or mental health problems.
  • Increased tolerance or need for more significant amounts of Clonidine to feel its effects.
  • Have withdrawal symptoms when you stop using Clonidine or use the medication to avoid withdrawal symptoms.

People who have participated in the prolonged use of Clonidine can become physically dependent on the substance.

It is dangerous to stop taking Clonidine suddenly because it can cause a dangerous withdrawal reaction. Withdrawal symptoms related to Clonidine include:

  • Tremors
  • Headaches.
  • Increased agitation.
  • Nervous behavior
  • A vertiginous increase in arterial influence.

You may be at higher risk for increased blood pressure if you take Clonidine in large doses or take it along with another blood pressure medicine called a beta-blocker.

In rare cases, this reaction can be fatal. Do not stop taking the clonidine medication on your own. If you need to stop taking Clonidine, your doctor will gradually advise you to reduce your dose for several days.

The symptoms have become so severe in some cases that they have led to death, demonstrating the severity of clonidine withdrawal. Those who witness these symptoms in an individual should immediately contact medical professionals.

Most mild long-term effects of clonidine use can be significantly reduced with therapy, but some products can cause long-term problems.

What preparations are available?

  • Tablets (immediate release): 0.1mg, 0.2mg and 0.3mg.
  • Transdermal patches: 0.1mg, 0.2mg and 0.3mg administered for 24 hours.

Well, it is absorbed after oral administration. The bioavailability after chronic administration is approximately 65%.

How should I keep Clonidine stored?

  • Tablets and patches should be kept at room temperature, 15 ° C – 30 ° C (59 ° F – 86 ° F).

Brand names

As of June 2017, Clonidine was marketed under many brands around the world:

Arkadin, Aruclonin, Atensina, Catapin, Catapres, Catapresan, Catapressan, China, Chlofazoline, Chlophazolin, Clonid-Ophtal, Clonidine, Clonidine, Clonidinã, Clonidine, Clonidine hydrochloride, Clonidinhydrochlorid, Clonidine, Clonidinum, Cloning.

También Clonistada, Clonnirit, Clophelinum, Dixarit, Duraclon, Edolglau, Haemiton, Hypodine, Hypolax, Iporel, Isoglaucon, Jenloga, Kapvay, Klofelino, Kochaniin, Melzin, Menograine, Normopresan, Paracefan, Pinsanidine, Run Rui y Winpress.

It was marketed as a combination drug with chlorthalidone such as Arkamin-H, Bemplas, Catapres-IUD, and Clorpres, combined with Bendroflumethiazide as Pertenso.

Taking, ingestion, and overdose of Clonidine

Symptoms of a clonidine overdose may include:

  • High blood pressure is followed by low blood pressure.
  • Difficult breathing
  • Low body temperature
  • Drowsiness.
  • Weakness.
  • Irritability.

Symptoms usually appear 30 minutes after an overdose, and children are much more likely to have overdose symptoms than adults.

A large overdose can cause abnormal heart rhythms, inability to breathe, seizures, and coma.

If you think someone else or have ingested an overdose of Clonidine, call an emergency or contact a poison control center.

Do not take more doses of Clonidine or less; take exactly as directed by your treating doctor.

If you forget or miss a dose of the clonidine medication, take that missed or missed dose as soon as you remember. If it is almost time to take your following amount of Clonidine, skip that missed or missed dose and continue your regular dosing schedule. Never double your dose to make up for the dose you forgot.