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 Clonidine. If you are concerned about side effects, discuss the risks and benefits of Clonidine with your doctor.

The following side effects have been reported by at least 1% of people taking Clonidine. 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.

• decreased sexual ability
• Constipation
• dizziness
• drowsiness
• Dry Mouth
• fatigue
• feeling unwell
• headache
• nausea and vomiting
• tiredness
• trouble sleeping

Although most of these 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:

• confusion
• difficulty changing visual focus
• difficulty urinating
• dizziness, lightheadedness, or fainting - especially when getting up from a lying or sitting position
• joint pain
• muscle pain or cramps
• paleness or cold feeling in fingertips and toes
• seeing or hearing things that are not there (hallucinations)
• signs of liver problems (e.g., nausea, vomiting, Diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• skin rash
• slow, fast or pounding heart beat
• symptoms of blockage of the large bowel (e.g., constipation, vomiting, liver problems)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of a serious allergic reaction (e.g., Hives; difficulty breathing; or swelling of the face, mouth, tongue, or throat)

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 Clonidine.

0.025 mg
Each blue, round, biconvex, film-coated tablet engraved "N" on one side contains 0.025 mg of clonidine hydrochloride. Nonmedicinal ingredients: colloidal silicon dioxide, dibasic calcium phosphate, lactose monohydrate (spray dried), magnesium stearate, pregelatinized starch, FD&C Blue No. 2, hypromellose, polyethylene glycol, polyvinyl alcohol - partially hydrolyzed, talc, and titanium dioxide.

0.1 mg
Each white, round, flat-faced, bevel-edged, compressed tablet engraved with "no | ov" on one side and "0.1" on the other contains 0.1 mg of clonidine as clonidine hydrochloride. Nonmedicinal ingredients: colloidal silicon dioxide, dibasic calcium phosphate, lactose monohydrate (spray dried), magnesium stearate and pregelatinized starch.

0.2 mg
Each orange coloured, round, flat-faced, bevel-edged, compressed tablet engraved with "no | ov" on one side and "0.2" on the other contains 0.2 mg of clonidine as clonidine hydrochloride. Nonmedicinal ingredients: colloidal silicon dioxide, dibasic calcium phosphate, FD&C Yellow No. 6 Lake, lactose monohydrate (spray dried), magnesium stearate and pregelatinized starch.

Do not take Clonidine if you:

• are allergic to clonidine or any ingredients of Clonidine
• have a certain type of abnormal heart rhythm associated with a low heart rate

There may be an interaction between clonidine and any of the following:

• alcohol
• Aldesleukin
• alpha-blockers (e.g., Alfuzosin, Doxazosin, Tamsulosin)
• amifostine
• Amiodarone
• amphetamines (e.g., Dextroamphetamine, lisdexamphetamine)
• angiotensin converting enzyme inhibitors (ACEIs; Captopril, Enalapril, Ramipril)
• angiotensin receptor blockers (ARBs; e.g., Candesartan, Irbesartan, Losartan)
• antihistamines (e.g,. cetirizine, doxylamine, Diphenhydramine, Hydroxyzine, Loratadine)
• antipsychotics (e.g., Chlorpromazine, Clozapine, Haloperidol, Olanzapine, Quetiapine, Risperidone)
• azelastine
• barbiturates (e.g., butalbital, pentobarbital, Phenobarbital)
• benzodiazepines (e.g., Alprazolam, Diazepam, Lorazepam)
• beta-adrenergic blockers (e.g., atenolol, metoprolol, Propranolol, Sotalol)
• brimonidine
• Buprenorphine
• Buspirone
• calcium channel blockers (e.g., Diltiazem, Verapamil)
• Ceritinib
• chloral hydrate
• Digoxin
• diuretics (water pills; e.g., Aliskiren, Furosemide, hydrochlorothiazide, triamterene)
• Donepezil
• Dronedarone
• efavirenz
• ephedrine
• Epinephrine
• Fingolimod
• Galantamine
• general anesthetics (medications used to put people to sleep before surgery)
• Guanfacine
• Lanreotide
• levodopa
• Methadone
• Methylphenidate
• Minocycline
• Minoxidil
• Mirtazapine
• muscle relaxants (e.g., Baclofen, Cyclobenzaprine, methocarbamol, orphenadrine)
• Nabilone
• narcotic pain relievers (e.g., Codeine, Fentanyl, Morphine, Oxycodone)
• nitrates (e.g., Nitroglycerin, isosorbide dinitrate, isosorbide mononitrate)
• nonsteroidal anti-inflammatory drugs (NSAIDs; e.g., Indomethacin, Naproxen, Diclofenac)
• Octreotide
• Olopatadine
• other alpha agonists (e.g., methyldopa)
• Pasireotide
• penoxifylline
• phosphodiesterase-5 inhibitors (e.g., Sildenafil, Tadalafil, Vardenafil)
• Pramipexole
• Propafenone
• Pseudoephedrine
• Rituximab
• Rivastigmine
• Ropinirole
• Rotigotine
• Rufinamide
• scopolamine
• seizure medications (e.g., Carbamazepine, Clobazam, , Levetiracetam, phenobarbital, Phenytoin, primidone, Topiramate, Valproic acid, zonisamide)
• selective serotonin reuptake inhibitors (SSRIs; e.g., Citalopram, Duloxetine, Fluoxetine, Paroxetine, Sertraline)
• serotonin/norepinephrine reuptake inhibitors (SNRIs; e.g., Desvenlafaxine, duloxetine, Venlafaxine)
• Tapentadol
• tetrahydrocannabinol
• thalidomide
• Tizanidine
• Tramadol
• tricyclic antidepressants (e.g., Clomipramine, Desipramine, Imipramine)
• Zolpidem
• Zopiclone

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. 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 Clonidine. 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.

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 Clonidine.

Depression: Clonidine can cause symptoms of depression. If you have a history of depression, discuss with your doctor how Clonidine may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Clonidine, and whether any special monitoring is needed. If you experience symptoms of depression such as poor concentration, changes in weight, changes in sleep, or decreased interest in activities, or notice them in a family member who is taking Clonidine, contact your doctor as soon as possible.

Drowsiness/reduced alertness: Clonidine can cause drowsiness and dizziness and may affect the ability of your eyes to change focus quickly between distance and close up. Avoid driving, operating machinery, or performing other potentially hazardous tasks until you have determined how you are affected by Clonidine.

Eyes: Clonidine may affect the eye. People taking clonidine should receive periodic eye examinations. Clonidine can cause decreased tear production, and contact lenses may become uncomfortable to wear.

Heart or blood vessel disease: Clonidine lowers blood pressure, which can cause worsening of heart conditions that are affected by decreased blood flow. If you have severe heart or blood vessel disease, have recently had a Heart Attack or Stroke, or a slow heart rate, discuss with your doctor how Clonidine may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Clonidine, and whether any special monitoring is needed.

Kidney function: Kidney Disease or decreased kidney function can cause Clonidine to build up in the body, causing side effects. If you have reduced kidney function, discuss with your doctor how Clonidine may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Clonidine, and whether any special monitoring is needed.

Lactose: Clonidine may contain lactose. If you have galactose intolerance, the Lapp lactase deficiency, or glucose-galactose malabsorption, you should not take Clonidine without talking to your doctor.

Other medical conditions: If you have polyneuropathy or constipation, discuss with your doctor how Clonidine may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Clonidine, and whether any special monitoring is needed.

Raynaud's disease: If you have Raynaud's disease, discuss with your doctor how Clonidine may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Clonidine, and whether any special monitoring is needed.

Surgery: If you are having any type of surgery, make sure that the doctors involved in your care are aware that you are taking Clonidine.

Withdrawal: Don't stop taking Clonidine 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, restlessness, pounding heartbeat, nausea, and headache. When stopping clonidine therapy, your 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 who are taking another type of blood pressure medication called a beta-blocker (e.g., Atenolol, Metoprolol, Bisoprolol) at the same time.

Pregnancy: When taken during pregnancy, clonidine crosses the placenta and may cause the developing baby’s heart rate to slow.

Clonidine should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Clonidine, contact your doctor immediately.

Breast-feeding: Clonidine passes into breast milk. If you are a breast-feeding mother and are taking clonidine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding. Clonidine is not recommended for women who are breast-feeding.

Children: The safety and effectiveness of using Clonidine have not been established for children.

Clonidine belongs to the group of medications called antihypertensives or vascular stabilizers. It 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. Clonidine works by widening the blood vessels, which increases blood flow and lowers blood pressure.

Clonidine can also be used to relieve menopausal hot flashes when hormone replacement therapy is not needed or not desired. For hot flashes, clonidine works by helping reduce the response of the blood vessels to stimuli that cause them to narrow and widen.

Clonidine may be available under multiple brand names and/or in several different forms. Any specific brand name of Clonidine may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of Clonidine may not be used for all of the conditions discussed here.

Your doctor may have suggested Clonidine for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking Clonidine, speak to your doctor. Do not stop taking Clonidine without consulting your doctor.

Do not give Clonidine to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take Clonidine if their doctor has not prescribed it.