Chlorthalidone side effects and drug information

Chlorthalidone is utilized for the treatment of high blood pressure. At the same time, it is used to cure edema, which is swelling due to the buildup of fluid in the body. Moreover, edema can be caused by various conditions like liver, kidney, or heart disease.

Trade name Hygroton, Thalitone
ChEMBL Id 1055
ChemSpider ID 2631
CAS ID 77-36-1
Molar mass 338.766 g/mol



Chlorthalidone is a kind of prescription drug in tablet form and taken by mouth.


The tablet is purchased as a generic drug. In this case, a generic drug is one that costs less compared to brand-name counterparts.

The prescription drug can be taken along with other medications for high blood pressure.


How it works

Chlorthalidone is included in the class of drugs known as diuretics. The so-called “class of drugs” is a group of medicines that have the same functions. Such drugs are used for the treatment of similar conditions.

 Chlorthalidone also helps the body to get rid of extra salt and water through the urine. It even helps lower blood pressure and fluid buildup, which leads to reduced swelling.

Side Effects

As an oral tablet, Chlorthalidone can cause drowsiness. It might also trigger other forms of side effects.


More common side effects

The more popular side effects that could happen when taking a chlorthalidone tablet include:


Different stomach problems like:

  • vomiting
  • nausea
  • diarrhea
  • stomach cramping
  • dizziness
  • Constipation
  • headache
  • loss of appetite
  • increased thirst

Side effects

Immediately call a doctor if the following serious side effects are experienced. Call 911 as soon as possible if the symptoms that you have feel life-threatening or if it seems like you have a medical emergency. The severe side effects and the symptoms that come with them may include the following:


  • Fever and sore throat
  • unusual bruising or bleeding
  • severe skin rash that may come with peeling of the skin
  • Difficulty swallowing or breathing
  • lesser potassium levels, accompanied by the following symptoms:
  • extreme thirst
  • drowsiness
  • tiredness
  • restlessness
  • Cramps and muscle pains
  • Vomiting or nausea
  • faster heart rate

Indication and dosage

The information that follows is intended for chlorthalidone oral tablets. Any possible dosages and forms might not be included. Your dosage, form, and how many times you take the table will depend on the following:


  • your age
  • the condition that you are being treated
  • how severe your condition is
  • other types of medical conditions you may have
  • how your body reacts to the first dosage

Forms and strengths

Generic: Chlorthalidone

  • Form: oral tablet
  • Strengths: 25 mg, 50 mg

Drug Interaction

Chlorthalidone drugs have no known serious interactions with other types of drugs.


Serious interactions may comprise of the following:


  • aminolevulinic acid
  • cisapride
  • amisulpride
  • squill
  • Isocarboxazid
  • tretinoin
  • methyl aminolevulinate
  • tretinoin topical

Chlorthalidone also has moderate interactions with about 154 different drugs.


Chlorthalidone may have minor interactions with about 147 different drugs.


The stated information does not include all adverse effects and possible interactions. Therefore, before using the said product, inform your pharmacist or pharmacist of any other product that you are using. It will also help if you can compile a list of all the medications with you. You can share this information with your pharmacist or doctor. Additionally, be sure to check with your doctor or healthcare professional for more medical advice, or if you happen to have health-related concerns, questions, or for additional information about the medicine.


Warnings and Precautions

Concerns that are related to the adverse effects of the drug:


  • Electrolyte disturbances: Hypochloremic alkalosis, hypokalemia, hypomagnesemia, and hyponatremia might happen. Also, the development of electrolyte disturbances could be lessened when used in combination with other types of electrolyte sparing antihypertensives.
  • Gout: In some patients who have a history of gout or a familial predisposition to gout, or those with chronic renal failure, gout could be precipitated. The risk increases with doses of ≥25 mg.
  • Hypersensitivity reactions: It is possible to experience hypersensitivity when taking the drug. The risk may increase in patients who have a history of bronchial asthma or allergy.
  • Photosensitivity: Photosensitization might occur.
  • Allergy to Sulfonamide (“sulfa”): The Food and Drug Administration (FDA)-approved product labeling for most medications that contain a sulfonamide chemical group comprises a wide contra-indication among patients who have prior allergic reactions to sulfonamides. Also, there is a possibility for cross-reactivity between the members of a particular class. However, the concerns for cross-reactivity have been extended to all other compounds that contain a sulfonamide structure.

Existing drug therapy issues:


  • Drug-drug interactions: Possible significant interactions might exist; thus, the need to adjust the dosage or dose or frequency, added monitoring, or choosing an alternative therapy. For more information on this, you may consult the drug interactions database.

Special populations:


  • Surgical patients: When administered in the morning of the surgery, thiazide diuretics could render the patient volume-depleted, and blood pressure might be labile during general anesthesia.

Overdose and Contraindication

Hypersensitivity to the drug or other sulfonamide-derived drugs or any component of the formulation; anuria


Note: The approved product labeling of FDA declares this medicine is contra-indicated with other drug classes; despite such, some challenged the scientific basis of the statement. You may refer to the Warnings and Precautions for more information.


The documentation of any allergenic cross-reactivity for drugs thiazide-type diuretics is minimal. But due to the similarities in their chemical structure or pharmacologic actions, the chances of cross-sensitivity could not be ruled out with great certainty.

Clinical Pharmacology

Sulfonamide-derived diuretics that restrains sodium and chloride reabsorption in the cortical-diluting segment of the ascending loop of Henle






Urine (primarily as unchanged drug)


Onset of Action

~2.6 hours; Peak effect: 2 – 6 hrs (Carter 2004)


Duration of Action

Single-dosage: 24 – 48 hrs; Long-term dose: 48 – 72 hours (Carter 2004)


Half-Life Elimination

Single-dosage 40-hrs; Long-term dose: 45 – 60 hours (Carter 2004); maybe prolonged with renal impairment


Protein Binding

~75% (58% to albumin)

Medication Guide

Keep in mind to keep the drug and other medicines away from children. Also, you should never share your medicine with others and only use the medication for the indication prescribed.


Be sure to consult your healthcare provider to make sure the information displayed on the page applies to your situation.