![]()
Brand Names: Apo-Clonidine
Common Name: clonidine HCl
What is this drug used for?
Clonidine is used alone or in combination with thiazide diuretics (e.g., hydrochlorothiazide) to treat high blood pressure. It is usually tried when other types of blood pressure medications are ineffective or cannot be used.
Your doctor may have suggested this medication for conditions other than the ones listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
Is there any reason not to take this drug?
This medication should not be taken by anyone who :
- is allergic to clonidine or to any of the ingredients of the medication
- has a certain type of abnormal heart rhythm associated with a low heart rate
What about possible side effects?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
More common:
- constipation
- dizziness
- drowsiness
- dryness of mouth
- unusual tiredness or weakness ?
Less common:
- 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
Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
Less common:
- depression
- swelling of feet and lower legs
Rare:
- paleness or cold feeling in fingertips and toes
- vivid dreams or nightmares
Check with your doctor immediately if any of the following side effects occur (signs of overdose):
- difficulty in breathing
- dizziness (extreme) or faintness
- feeling cold
- pinpoint pupils of eyes
- slow heartbeat
- unusual tiredness or weakness
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
What if I am taking other drugs?
There may be an interaction between clonidine and any of the following:
- ACE inhibitors (e.g., enalapril, lisinopril)
- alcohol
- appetite suppressants
- barbiturates (e.g., phenobarbital)
- beta-blockers (e.g., atenolol, metoprolol)
- calcium channel blockers (e.g., diltiazem, verapamil)
- chlorpromazine
- cyclosporine
- digoxin
- diuretics (e.g., furosemide, hydrochlorothiazide)
- fluphenazine
- levodopa
- MAO inhibitors (e.g., phenelzine)
- neuroleptics (e.g., haloperidol)
- nonsteroidal anti-inflammatory drugs (e.g., indomethacin, naproxen, diclofenac)
- prazosin
- tricyclic antidepressants (e.g., amitriptyline, imipramine)
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. In many cases, interactions are intended or are managed by close monitoring. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.
Other information:
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Withdrawal: Don't stop taking this medication without talking to your doctor. A severe withdrawal reaction may develop within 12 to 48 hours when clonidine is stopped suddenly. This reaction includes a rapid rise in blood pressure and symptoms such as nervousness, agitation, chest pain, pounding heartbeat, increased salivation, trembling hands, stomach cramps, trouble sleeping, vomiting, and headache. When stopping clonidine therapy, the doctor will instruct you to reduce the dose gradually over 2 to 4 days to avoid this reaction. A withdrawal reaction is most likely to occur in people who have been receiving large doses of clonidine or in those who are taking another type of blood pressure medicaiton called a beta-blocker at the same time. Examples of beta-blockers are atenolol, metoprolol, and propranolol.
Depression: People with a history of depression should let their doctor know if their depression worsens or returns while on this medication.
Drowsiness/reduced alertness: Clonidine can cause drowsiness. Do not operate automobiles or other machinery until you have determined that it does not produce this effect on you.
Eyes: People treated with clonidine should receive periodic eye examinations.
Heart or blood vessel disease: Because it lowers blood pressure, people with severe heart disease or blood vessel disease, or a recent heart attack or stroke, should be closely monitored by their doctor while taking clonidine.
Kidney failure: People with chronic kidney failure should be monitored by their doctor while taking clonidine.
Raynaud's disease: People with Raynaud's disease should be cautious while taking clonidine as it may worsen this condition.
Pregnancy: There are no adequate studies of the use of this medication by pregnant women. It should be used during pregnancy only if clearly needed.
Breast-feeding: Since clonidine passes into breast milk, it should not be used by nursing women.
Children: The safety and effectiveness of this medication have not been established for use by children.
Special Instructions:
For treatment of high blood pressure, the dose of clonidine ranges from 0.1 mg to 0.6 mg daily, usually in two divided doses (morning and bedtime), depending on the needs and circumstances of the person taking the medication.
Do not stop taking this medication suddenly without checking with your doctor.
Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.
© MediResource Inc. Terms and conditions of use: The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.