Chlorthalidone is a week thiazide diuretic that is used (along with other appropriate drugs) in the treatment of the following conditions:

• Edema brought on by kidney illness, cirrhosis, heart failure, or corticosteroid and oestrogen medication.
• Management of hypertension especially in patients who require monotherapy in the absence of other comorbid conditions like diabetes, ischemic heart disease, and cerebrovascular diseases.
• Hypercalciuria and patients predisposed to develop calcium stones.

Chlorthalidone Dose in Adults

• Edema:
  • Every 24 hours, 50 to 100 mg, or 100 mg every other day, up to a daily maximum of 200 mg.
• Patients with Heart failure:
  • 100 mg per day is the maximum dosage, or 12.5 to 25 mg once every 24 hours.

• Hypertension:
  • 12.5 to 25 mg once every 24 hours, tapered by 25 mg daily, up to a daily maximum of 100 mg.

• Off-label use in patients with hypercalciuria and calcium stones:
  • 25 mg once daily

Chlorthalidone Dose in Children

Dose of chlorthalidone in children & adolescents with Hypertension:

• To a maximum dose of 2 mg/kg/day or 50 mg/day, administer 0.3 mg/kg/dose once every 24 hours, preferably in the morning.

Pregnancy Risk Factor C

• The palcenta is crossed by chlorthalidone and could be associated with the adverse events listed below:
  • Neonatal or fetal jaundice
  • Thrombocytopenia and
  • It can also cause other adverse reactions similar to those experienced by adults.
• Women who were treated with thiazide diuretics before conception can continue to use the drug during pregnancy.(Hypertension in Pregnancy ACOG 2007(

Use of chlorthalidone during breastfeeding  

• The breastmilk may contain thiazide diuretics, which can cause severe neonatal side effects. 
• Breastfeeding and thiazide diuretics should not be done during breastfeeding.
• Milk production is also affected by diuretics.

Chlorthalidone Dose in Renal Disease:

• Chlorthalidone is contraindicated in patients with anuria.
• In individuals with ESRD and advanced renal impairment (CrCl of less than 10 ml/min), it is ineffective.
• Patients with a CrCl of 10 ml/min or higher do not require a dosage change.

Chlorthalidone Dose in Liver Disease:

• It should be used with caution in patients with liver disease.

Chlorthalidone Side effects:

• Cardiovascular:
  • Necrotizing angiitis
  • Orthostatic hypotension
  • Vasculitis
• Central nervous system:
  • Dizziness
  • Headache
  • Paresthesia
  • Restlessness
  • Vertigo
• Dermatologic:
  • Skin photosensitivity
  • Skin rash
  • Toxic epidermal necrolysis
  • Urticaria
• Endocrine & metabolic:
  • Glycosuria
  • Hyperglycemia
  • Hyperuricemia
  • Hypochloremic alkalosis
  • Hypokalemia
  • Hyponatremia
• Gastrointestinal:
  • Abdominal cramps
  • Anorexia
  • Constipation
  • Diarrhea
  • Gastric irritation
  • Nausea
  • Pancreatitis
  • Vomiting
• Genitourinary:
  • Impotence
• Hematologic & oncologic:
  • Agranulocytosis
  • Aplastic anemia
  • Hypersensitivity angiitis
  • Leukopenia
  • Nonthrombocytopenic purpura
  • Thrombocytopenia
• Hepatic:
  • Intrahepatic cholestatic jaundice
• Neuromuscular & skeletal:
  • Asthenia
  • Muscle spasm
• Ophthalmic:
  • Xanthopsia

Contraindication to Chlorthalidone include:

• Hypersenstivity
• Anuria is a low urine output of less than 100ml within the last 24 hours.

Warnings and Precautions

• Electrolyte imbalance:
  • Chlorthalidone therapy patients may experience any of these electrolyte imbalances.
    • Hypokalemia
    • Hypochloremic alkalosis
    • Hypomagnesemia is a condition in which there is hypomagnesemia.
    • Hyponatremia
    • Combining chlorthalidone and other drugs, such as ACE inhibitors or ARBs, can help to prevent electrolyte imbalances.
• Gout:
  • It can precipitate gout in patients with:
    • a history of gout
    • a familial predisposition to gout
    • chronic renal failure
    • Patients at higher risk of hyperuricemia are those whose daily intake exceeds 50 mg/day.
• Hypersensitivity reactions:
  • Patients with asthma and atopy are at-risk of developing allergic reactions to chlorthalidone.
• PhotosensitivityPossible side effects of the drug
• Allergy to sulfonamide ("sulfa")
  • Patients who have a history of severe reactions to sulfa drugs, especially those with severe allergies, should be screened.Steven-Johnson syndrome, TENAvoid chlorthalidone

• Insufficiency of the adrenals:
  • Patients suffering from adrenal insufficiency should avoid this drug. Patients with adrenal insufficiency should avoid the drug.

• Diabetes:
  • It can cause glucose problems in patients who are already diabetic or have pre-diabetic.

• Hepatic impairment
  • This could lead to hepatic and/or metabolic encephalopathy in patients with advanced liver disease.
• Hypercalcemia:
  • Patients suffering from hypercalcemia should stay away from thiazide diuretics, as they can inhibit calcium excretion from the renal tubules.
• Hypercholesterolemia:
  • Patients with dyslipidemias, particularly those with high triglyceride levels should be cautious when using thiazide diuretics.
• Parathyroid disease
  • Before testing for parathyroid hormone, you should stop taking thiazide Diuretics.
  • In individuals getting treatment with thiazide diuretics, pathological alterations brought on by hypophosphatemia and hypercalcemia have been seen.

• Renal impairment
  • Patients with extensive renal illness, anuria, or rapidly fluctuating renal functions shouldn't undergo this procedure.

• Systemic lupus erythematosus (SLE):
  • The drug-induced SLE caused by chlorthalidone could be accompanied by positive anti-histoen antibody.

Chlorthalidone: Drug Interaction

Note: Drug Interaction Categories:

• Risk Factor C: Monitor When Using Combination
• Risk Factor D: Consider Treatment Modification
• Risk Factor X: Avoid Concomitant Use

Monitoring parameters:

While on chlorthalidone therapy, Monitor:

• Weight (an indirect evidence of body fluid balance)
• intake and output records daily to determine fluid status
• Blood pressure (The target blood pressure in a patient with ASCVD risk of more than 10% is less than 130/80 mmHg.
• serum electrolytes, and
• renal functions

How to administer Chlorthalidone?

• Take the tablet orally after breakfast (after the morning meal).

Mechanism of action of Chlorthalidone:

• Chlorthalidone, a diuretic produced from sulfonamides, prevents salt and chloride from being reabsorbed in the ascending loops of Henle.

Peak effects appear between two and six hours after the beginning of activity, on average.

After a single dose, the duration of effect ranges from 24 to 48 hours. The liver metabolises the medication, which is attached to proteins in 75% of its composition.

The drug's half-life ranges from 40 to 60 hours, however it can be extended in individuals with renal impairment.

It is priamrily excreted via the kidneys

International brands of Chlorthalidone:

• C-Done
• Chotalin
• Clortalil
• Dichlor
• Dinorik
• Higroton
• Hygroton
• Hythalton
• Igroton
• Metorene
• Nefrofil
• Oxodoline
• Saluretin
• Thalin
• Tonorma
• Unichlor

Chlorthalidone Brands in pakistan:

Chlorthalidone tablets in Pakistan