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Clonidine (Systemic)

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Clonidine (Systemic)

US Brand Names

• Catapres

• Catapres-TTS-1

• Catapres-TTS-2

• Catapres-TTS-3

Canadian Brand Names

• Catapres

• Dixarit


Clonidine (KLON-i-deen) belongs to the general class of medicines called antihypertensives. It is used to treat high blood pressure (hypertension).

High blood pressure adds to the work load of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. This can damage the blood vessels of the brain, heart, and kidneys, resulting in a stroke, heart failure, or kidney failure. Hypertension may also increase the risk of heart attacks. These problems may be less likely to occur if blood pressure is controlled.

Clonidine works by controlling nerve impulses along certain nerve pathways. As a result, it relaxes blood vessels so that blood passes through them more easily. This helps to lower blood pressure.

Clonidine may also be used for other conditions as determined by your doctor.

Clonidine is available only with your doctor's prescription, in the following dosage forms:


    • Tablets (U.S. and Canada)


    • Skin patch (U.S.)

Special Considerations

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For clonidine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to clonidine. Also tell your health care professional if you are allergic to any other substance, such as foods, preservatives, or dyes.


Clonidine has not been studied in pregnant women. However, studies in animals have shown that clonidine causes harmful effects in the fetus, but not birth defects.


Although clonidine passes into breast milk, it has not been reported to cause problems in nursing babies.


Children may be more sensitive than adults to clonidine. Clonidine overdose has been reported when children accidentally took this medicine.

Older adults

Dizziness or faintness may be more likely to occur in the elderly, who are more sensitive than younger adults to the effects of clonidine.

Other medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking clonidine, it is especially important that your health care professional know if you are taking any of the following:

    • Beta-blockers (acebutolol [e.g., Sectral], atenolol [e.g., Tenormin], betaxolol [e.g., Kerlone], carteolol [e.g., Cartrol], labetalol [e.g., Normodyne], metoprolol [e.g., Lopressor], nadolol [e.g., Corgard], oxprenolol [e.g., Trasicor], penbutolol [e.g., Levatol], pindolol [e.g., Visken], propranolol [e.g., Inderal], sotalol [e.g., Sotacor], timolol [e.g., Blocadren])-These medicines may increase the risk of harmful effects when clonidine treatment is stopped suddenly

    • Tricyclic antidepressants (amitriptyline [e.g., Elavil], amoxapine [e.g., Asendin], clomipramine [e.g., Anafranil], desipramine [e.g., Pertofrane], doxepin [e.g., Sinequan], imipramine [e.g., Tofranil], nortriptyline [e.g., Aventyl], protriptyline [e.g., Vivactil], trimipramine [e.g., Surmontil])-These medicines may decrease clonidine's effects on blood pressure

Other medical problems

The presence of other medical problems may affect the use of clonidine. Make sure you tell your doctor if you have any other medical problems, especially:

    • Heart or blood vessel disease-Clonidine may make these conditions worse

    • Irritated or scraped skin (with transdermal system [skin patch] only)-The effects of clonidine may be increased if the skin patch is placed on an area of scraped or irritated skin because more medicine is absorbed into the body

    • Kidney disease-Effects of clonidine may be increased because of slower removal of clonidine from the body

    • Mental depression (history of) or

    • Raynaud's syndrome-Clonidine may make these conditions worse

    • Polyarteritis nodosa or

    • Scleroderma or

    • Systemic lupus erythematosus (SLE) (with transdermal system [skin patch] only)-Effects of clonidine may be decreased because absorption of this medicine into the body is blocked


For patients taking this medicine for high blood pressure :

    • In addition to the use of the medicine your doctor has prescribed, treatment for your high blood pressure may include weight control and care in the types of foods you eat, especially foods high in sodium. Your doctor will tell you which of these are most important for you. You should check with your doctor before changing your diet.

    • Many patients who have high blood pressure will not notice any signs of the problem. In fact, many may feel normal. It is very important that you take your medicine exactly as directed and that you keep your appointments with your doctor even if you feel well.

    • Remember that this medicine will not cure your high blood pressure but it does help control it. Therefore, you must continue to use it as directed if you expect to lower your blood pressure and keep it down. You may have to take high blood pressure medicine for the rest of your life . If high blood pressure is not treated, it can cause serious problems such as heart failure, blood vessel disease, stroke, or kidney disease.

For patients using the transdermal system (skin patch) :

    • Use this medicine exactly as directed by your doctor . It will work only if applied correctly. This medicine usually comes with patient instructions. Read them carefully before using .

    • Do not try to trim or cut the adhesive patch to adjust the dosage. Check with your doctor if you think the medicine is not working as it should.

    • Apply the patch to a clean, dry area of skin on your upper arm or chest. Choose an area with little or no hair and free of scars, cuts, or irritation.

    • The system should stay in place even during showering, bathing, or swimming. If the patch becomes loose, cover it with the extra adhesive overlay provided. Apply a new patch if the first one becomes too loose or falls off.

    • Each dose is best applied to a different area of skin to prevent skin problems or other irritation.

    • After removing a used patch, fold the patch in half with the sticky sides together. Make sure to dispose of it out of the reach of children.

To help you remember to use your medicine, try to get into the habit of using it at regular times. If you are taking the tablets, take them at the same time each day. If you are using the transdermal system (skin patch), try to change it at the same time and day of the week.


The dose of clonidine will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of clonidine used for the treatment of high blood pressure. If your dose is different, do not change it unless your doctor tells you to do so:

    • For oral dosage form (tablets):

      o For high blood pressure:

        Adults-100 mcg (0.1 mg) two times a day. Your doctor may increase your dose up to 200 mcg (0.2 mg) to 600 mcg (0.6 mg) a day taken in divided doses.

        Children-Use and dose must be determined by your doctor.

    • For transdermal dosage form (skin patch):

      o For high blood pressure:

        Adults-One transdermal dosage system (skin patch) applied once a week.

        Children-Use and dose must be determined by your doctor.

Missed dose

If you miss a dose of this medicine, take it or use it as soon as possible. Then go back to your regular dosing schedule. If you miss two or more doses of the tablets in a row or if you miss changing the transdermal patch for 3 or more days, check with your doctor right away . If your body goes without this medicine for too long, your blood pressure may go up to a dangerously high level and some unpleasant effects may occur.


To store this medicine:

    • Keep out of the reach of children.

    • Store away from heat and direct light.

    • Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.

    • Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.


It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly.

Check with your doctor before you stop using this medicine . Your doctor may want you to reduce gradually the amount you are using before stopping completely.

Make sure that you have enough clonidine on hand to last through weekends, holidays, or vacations . You should not miss any doses. You may want to ask your doctor for another written prescription for clonidine to carry in your wallet or purse. You can then have it filled if you run out of medicine when you are away from home.

For patients taking this medicine for high blood pressure :

    • Do not take other medicines unless they have been discussed with your doctor . This especially includes over-the-counter (nonprescription) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, since they may tend to increase your blood pressure.

Clonidine will add to the effects of alcohol and other central nervous system (CNS) depressants (medicines that slow down the nervous system, possibly causing drowsiness). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine .

Clonidine may cause some people to become drowsy or less alert than they are normally. This is more likely to happen when you begin to take it or when you increase the amount of medicine you are taking. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert .

Before having any kind of surgery (including dental surgery) or emergency treatment, tell the medical doctor or dentist in charge that you are using this medicine .

Dizziness, lightheadedness, or fainting may occur after you take this medicine, especially when you get up from a lying or sitting position. Getting up slowly may help, but if the problem continues or gets worse, check with your doctor.

The dizziness, lightheadedness, or fainting is also more likely to occur if you drink alcohol, stand for long periods of time, exercise, or if the weather is hot. While you are taking clonidine, be careful to limit the amount of alcohol you drink. Also, use extra care during exercise or hot weather or if you must stand for a long time.

Clonidine may cause dryness of the mouth. For temporary relief, use sugarless candy or gum, melt bits of ice in your mouth, or use a saliva substitute. However, if your mouth continues to feel dry for more than 2 weeks, check with your medical doctor or dentist. Continuing dryness of the mouth may increase the chance of dental disease, including tooth decay, gum disease, and fungus infections.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Signs and symptoms of overdose

Difficulty in breathing; dizziness (extreme) or faintness; feeling cold; pinpoint pupils of eyes; slow heartbeat; unusual tiredness or weakness (extreme).

Check with your doctor as soon as possible if any of the following side effects occur:

More common

with transdermal system (skin patch) onlyItching or redness of skin.

Less common

Mental depression; swelling of feet and lower legs.


Paleness or cold feeling in fingertips and toes; vivid dreams or nightmares.

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

Constipation; dizziness; drowsiness; dryness of mouth; unusual tiredness or weakness.

Less common

Darkening of skin-with transdermal system (skin patch) only; decreased sexual ability; dizziness, lightheadedness, or fainting, especially when getting up from a lying or sitting position; dry, itching, or burning eyes; loss of appetite; nausea or vomiting; nervousness.

After you have been using this medicine for a while, it may cause unpleasant or even harmful effects if you stop taking it too suddenly. After you stop taking this medicine, check with your doctor immediately if any of the following occur:

Anxiety or tenseness; chest pain; fast or pounding heartbeat; headache; increased salivation; nausea; nervousness; restlessness; shaking or trembling of hands and fingers; stomach cramps; sweating; trouble in sleeping; vomiting.

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Additional Information

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, clonidine is used in certain patients with the following medical conditions:

    • Migraine headache

    • Symptoms associated with menopause or menstrual discomfort

    • Symptoms of withdrawal associated with alcohol, nicotine, or narcotics

    • Gilles de la Tourette's syndrome

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.

May 21, 1999

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