Catapres Side Effects

Generic name: clonidine

Medically reviewed by Drugs.com. Last updated on Feb 13, 2025.

Note: This document provides detailed information about Catapres Side Effects associated with clonidine. Some dosage forms listed on this page may not apply specifically to the brand name Catapres.

Applies to clonidine: oral tablet, oral tablet extended release.

Other dosage forms:

• epidural solution
• transdermal patch extended release

Precautions

It is important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for any unwanted effects.

Do not interrupt or Stop taking clonidine (the active ingredient contained in Catapres) without first checking with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping it completely. Your blood pressure may become worse when the medicine is stopped suddenly, which can cause serious side effects.

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 a second written prescription for clonidine to carry in your wallet or purse. You can have it filled if you run out of medicine when you are away from home.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements. You should avoid over-the-counter [OTC] 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. CNS depressants are medicines that slow down the nervous system and may cause drowsiness. Some examples of CNS depressants are antihistamines or medicine for hay fever, allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates or 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.

This medicine may cause dryness of the eyes. If you wear contact lenses, this may be a problem for you. Talk to your doctor if you wear contact lenses, and discuss how to treat the dryness.

Dizziness, lightheadedness, or fainting may occur after you take this medicine, especially when you get up suddenly 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 not to become dehydrated or overheated during exercise or hot weather or if you must stand for a long time.

If you develop a skin rash, hives, or any allergic reaction to this medicine, stop taking the medicine and check with your doctor as soon as possible.

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.

Common side effects of Catapres

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:

Serious side effects of Catapres

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:

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)

For healthcare professionals

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

General adverse events

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]

Dermatologic

• 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]

Endocrine

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

Gastrointestinal

• 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]

Genitourinary

• Common (1% to 10%): Erectile dysfunction
• Frequency not reported: Micturition difficulty, loss of libido, decreased sexual activity, nocturia, urinary retention^[Ref]

Cardiovascular

• 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]

Hematologic

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

Hepatic

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

Metabolic

• Rare (0.01% to 0.1%): Blood glucose increased, serum creatine phosphokinase increased
• Frequency not reported: Weight gain, anorexia^[Ref]

Musculoskeletal

• 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]

Ocular

• Rare (0.01% to 0.1%): Lacrimation decreased (dry eyes)
• Frequency not reported: Accommodation disorder, ocular burning, vision blurred^[Ref]

Other

• 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]

Psychiatric

• 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]

Respiratory

• Common (1% to 10%): Hypoventilation
• Rare (0.01% to 0.1%): Nasal dryness^[Ref]

See also:

Further information

Catapres side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer