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Clonidine Side Effects

Medically reviewed by Last updated on May 14, 2023.


Commonly reported side effects of clonidine include: drowsiness, fatigue, hypotension, lethargy, sedated state, headache, and upper abdominal pain. Other side effects include: dizziness. Continue reading for a comprehensive list of adverse effects.

Applies to clonidine: oral tablet, oral tablet extended release. Other dosage forms:

Serious side effects of Clonidine

Along with its needed effects, clonidine 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 while taking clonidine:

Less common

  • Mental depression
  • swelling of the feet and lower legs


  • Anxiety
  • blistering, burning, crusting, dryness, or flaking of the skin
  • chest pain or discomfort
  • confusion as to time, place, or person
  • decreased urine output
  • dilated neck veins
  • drowsiness
  • dry mouth
  • fast, pounding, or irregular heartbeat or pulse
  • fever
  • general feeling of discomfort or illness
  • holding false beliefs that cannot be changed by fact
  • hyperventilation
  • irregular breathing
  • irritability
  • itching, scaling, severe redness, soreness, or swelling of the skin
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • lightheadedness, dizziness, or fainting
  • mental depression
  • paleness or cold feeling in the fingertips and toes
  • pounding, slow heartbeat
  • problems in urination or increase in the amount of urine
  • raised red swellings on the skin, lips, tongue, or in the throat
  • restlessness
  • seeing or hearing things that are not there
  • shaking
  • shortness of breath
  • skin rash
  • swelling of the face, fingers, feet, or lower legs
  • tightness in the chest
  • tingling or pain in the fingers or toes when exposed to cold
  • trouble with sleeping
  • troubled breathing
  • unusual excitement, nervousness, or restlessness
  • unusual tiredness or weakness
  • vivid dreams or nightmares
  • weight gain
  • wheezing

Get emergency help immediately if any of the following symptoms of overdose occur while taking clonidine:

Symptoms of overdose

  • Dizziness (extreme) or faintness
  • feeling cold
  • pinpoint pupils of the eyes
  • unusual tiredness or weakness (extreme)

Other side effects of Clonidine

Some side effects of clonidine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

  • Darkening of the skin
  • decreased sexual ability
  • dry, itching, or burning eyes
  • loss of appetite
  • nausea or vomiting


  • Blurred vision
  • decreased interest in sexual intercourse
  • hair loss or thinning of the hair
  • inability to have or keep an erection
  • leg cramps
  • loss in sexual ability, desire, drive, or performance
  • muscle or joint pain
  • pale skin
  • swelling of the breasts or breast soreness in both females and males
  • weakness

For Healthcare Professionals

Applies to clonidine: compounding powder, injectable solution, oral suspension extended release, oral tablet, oral tablet extended release, transdermal film extended release.


Very common (10% or more): Hypotension (45%), orthostatic hypotension (32%)

Common (1% to 10%): Chest pain, tachycardia

Uncommon (0.1% to 1%): Sinus bradycardia, Raynaud's phenomenon, palpitations

Rare (0.01% to 0.1%): Atrioventricular block, palpitations, bradycardia, syncope, congestive heart failure, electrocardiographic abnormalities (i.e., sinus node arrest, high degree AV block), cerebrovascular accident

Frequency not reported: Bradyarrhythmia, hypertension, rebound hypertension[Ref]


Very common (10% or more): Contact dermatitis with the patch formulation (19%)

Common (1% to 10%): Sweating

Uncommon (0.1% to 1%): Pruritus, rash (localized or generalized), urticaria, erythema

Rare (0.01% to 0.1%): Alopecia, excoriation, burning

Very rare (less than 0.01%): Papules, throbbing, blanching, generalized macular rash, facial/tongue angioedema

Frequency not reported: Hives, localized hypo or hyper pigmentation[Ref]


Rare (0.01% to 0.1%): Gynecomastia[Ref]


Very common (10% or more): Dry mouth (40%), upper abdominal pain (15%), nausea (13%), vomiting (10%)

Common (1% to 10%): Constipation, parotid gland pain

Uncommon (0.1% to 1%): Colonic pseudo-obstruction

Very rare (less than 0.01%): Parotitis[Ref]


Common (1% to 10%): Erectile dysfunction

Frequency not reported: Micturition difficulty, loss of libido, decreased sexual activity, nocturia, urinary retention[Ref]


Most adverse effects are mild and diminish with continued therapy. The most frequent (which appear to be dose-related) are dry mouth (40%), drowsiness (33%), dizziness (16%), constipation (10%), and sedation (10%).[Ref]


Rare (0.01% to 0.1%): Peripheral blood flow disturbance, thrombocytopenia[Ref]


Frequency not reported: Mild transient abnormalities of liver function tests, hepatitis[Ref]


Rare (0.01% to 0.1%): Blood glucose increased, serum creatine phosphokinase increased

Frequency not reported: Weight gain, anorexia[Ref]


Frequency not reported: Muscle pain, joint pain, leg cramps[Ref]

Nervous system

Very common (10% or more): Drowsiness (33%), dizziness (16%), somnolence (13%), sedation (10%)

Common (1% to 10%): Headache

Uncommon (0.1% to 1%): Paresthesia

Frequency not reported: Headache, localized numbness[Ref]


Rare (0.01% to 0.1%): Lacrimation decreased (dry eyes)

Frequency not reported: Accommodation disorder, ocular burning, vision blurred[Ref]


Common (1% to 10%): Fatigue, tinnitus

Uncommon (0.1% to 1%): Malaise

Frequency not reported: Fever, pallor, weakness, positive Coombs' test, increased sensitivity to alcohol[Ref]


Very common (10% or more): Confusion (13%)

Common (1% to 10%): Depression, tearfulness, sleep disorder, hallucinations (both visual and auditory), nervousness, agitation

Uncommon (0.1% to 1%):

Rare (0.01% to 0.1%): Delusional perception, nightmare

Frequency not reported: Libido decreased, restlessness, anxiety, irritability, behavior changes[Ref]


Common (1% to 10%): Hypoventilation

Rare (0.01% to 0.1%): Nasal dryness[Ref]


1. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. "Product Information. CloNIDine Hydrochloride (clonidine)." Unichem Pharmaceuticals Inc (2016):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.