Clorpres Side Effects

Generic name: chlorthalidone / clonidine

Medically reviewed by Drugs.com. Last updated on Aug 15, 2023.

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

Applies to chlorthalidone / clonidine: oral tablet.

Common side effects of Clorpres

Some side effects of chlorthalidone / 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:

After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, Check with your doctor immediately if you notice the following side effects:

• 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

Serious side effects of Clorpres

Along with its needed effects, chlorthalidone/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 chlorthalidone / clonidine:

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 while taking chlorthalidone / clonidine:

Signs and symptoms of too much potassium loss

• dryness of mouth
• increased thirst
• irregular heartbeat
• mood or mental changes
• muscle cramps or pain
• nausea or vomiting
• weak pulse

Signs and symptoms of too much sodium loss

• confusion
• convulsions (seizures)
• decreased mental activity
• irritability
• muscle cramps
• unusual tiredness or weakness

Precautions

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 taking chlorthalidone / clonidine. Your doctor may want you to reduce gradually the amount you are taking before stopping the medicine completely.

Make sure that you have enough medicine on hand to last through weekends, holidays, or vacations. You should not miss taking any doses. You may want to ask your doctor for another written prescription 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.

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

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.

This medicine 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.

This medicine 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.

Dizziness, lightheadedness, or fainting may occur, 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. Drinking alcoholic beverages may also make the drowsiness worse. While you are taking this medicine, 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 long periods of time.

This medicine may cause a loss of potassium from your body.

• To help prevent this, your doctor may want you to:
  • eat or drink foods that have a high potassium content (for example, orange or other citrus fruit juices), or
  • take a potassium supplement, or
  • take another medicine to help prevent the loss of the potassium in the first place.
• It is very important to follow these directions. Also, it is important not to change your diet on your own. This is more important if you are already on a special diet (as for diabetes), or if you are taking a potassium supplement or a medicine to reduce potassium loss. Extra potassium may not be necessary and, in some cases, too much potassium could be harmful.

Check with your doctor if you become sick and have severe or continuing vomiting or diarrhea. These problems may cause you to lose additional water and potassium.

For patients with diabetes:

• The chlorthalidone contained in this medicine may raise blood sugar levels. While you are using this medicine, be sure to test your blood sugar (glucose) level, or test for sugar in your urine.

This medicine may cause your skin to be more sensitive to sunlight than it is normally. Exposure to sunlight, even for brief periods of time, may cause a skin rash, itching, redness or other discoloration of the skin, or a severe sunburn. When you begin taking this medicine:

• Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.
• Wear protective clothing, including a hat. Also, wear sunglasses.
• Apply a sun block product that has a skin protection factor (SPF) of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your health care professional.
• Apply a sun block for lips that has an SPF of at least 15 to protect your lips.
• Do not use a sunlamp or tanning bed or booth.

If you have a severe reaction from the sun, check with your doctor.

This medicine 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.

For healthcare professionals

Applies to chlorthalidone / clonidine: oral tablet.

General adverse events

The most frequent adverse reactions were dry mouth, drowsiness, dizziness, constipation, and sedation.^[Ref]

Gastrointestinal

• Very common (10% or more): Dry mouth (up to 40%), constipation (up to 10%)

Chlorthalidone:

• Frequency not reported: Gastric irritation, nausea, vomiting, cramping, diarrhea, constipation, pancreatitis

Clonidine:

• Common (1% to 10%): Nausea, vomiting
• Frequency not reported: Parotitis^[Ref]

Nervous system

• Very common (10% or more): Drowsiness (up to 33%), dizziness (up to 16%), sedation (up to 10%)

Chlorthalidone:

• Frequency not reported: Dizziness, vertigo, paresthesias, headache

Clonidine:

• Common (1% to 10%): Headache^[Ref]

Other

Chlorthalidone:

• Frequency not reported: Weakness

Clonidine:

• Very common (10% or more): Weakness (up to 10%)
• Common (1% to 10%): Malaise, fatigue, discontinuation syndrome
• Uncommon (0.1% to 1%): Gynecomastia
• Frequency not reported: Dryness, increased sensitivity to alcohol, fever^[Ref]

Cardiovascular

Chlorthalidone:

• Frequency not reported: Necrotizing angiitis, orthostatic hypotension

Clonidine:

• Common (1% to 10%): Orthostatic symptoms
• Uncommon (0.1% to 1%): Palpitations, tachycardia, bradycardia
• Frequency not reported: Raynaud's phenomenon, congestive heart failure, ECG abnormalities, sinus bradycardia, atrioventricular block, pallor^[Ref]

Dermatologic

Chlorthalidone:

• Frequency not reported: Purpura, photosensitivity, rash, urticaria, Lyell's syndrome

Clonidine:

• Common (1% to 10%): Rash
• Uncommon (0.1% to 1%): Pruritus, hives, angioneurotic edema, urticaria, alopecia^[Ref]

Genitourinary

Chlorthalidone:

• Frequency not reported: Glycosuria, impotence

Clonidine:

• Common (1% to 10%): Sexual activity decreased, impotence, nocturia
• Uncommon (0.1% to 1%): Difficulty in micturition, urinary retention^[Ref]

Hematologic

Chlorthalidone:

• Frequency not reported: Leukopenia, agranulocytosis, thrombocytopenia, aplastic anemia

Clonidine:

• Frequency not reported: Weakly positive Coombs' test^[Ref]

Hepatic

Chlorthalidone:

• Frequency not reported: Intrahepatic cholestatic jaundice

Clonidine:

• Common (1% to 10%): Mild transient abnormalities in liver function tests
• Frequency not reported: Hepatitis^[Ref]

Metabolic

Chlorthalidone:

• Frequency not reported: Anorexia, hyperglycemia, hyperuricemia

Clonidine:

• Common (1% to 10%): Anorexia, weight gain
• Frequency not reported: Transient elevation of blood glucose^[Ref]

Musculoskeletal

Chlorthalidone:

• Frequency not reported: Muscle spasm

Clonidine:

• Uncommon (0.1% to 1%): Muscle or joint pain, cramps of the lower limbs
• Frequency not reported: Transient elevation of serum creatine phosphokinase^[Ref]

Ocular

Chlorthalidone:

• Frequency not reported: Xanthopsia

Clonidine:

• Frequency not reported: Burning of the eyes, blurred vision^[Ref]

Psychiatric

Chlorthalidone:

• Frequency not reported: Restlessness

Clonidine:

• Common (1% to 10%): Nervousness, agitation, mental depression, loss of libido
• Uncommon (0.1% to 1%): Insomnia
• Frequency not reported: Vivid dreams, nightmares, behavioral changes, restlessness, anxiety, visual and auditory hallucinations, delirium^[Ref]

Renal

Clonidine:

• Frequency not reported: Dryness of the nasal mucosa^[Ref]

See also:

Further information

Clorpres 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