About Chlorthalidone
Chlorthalidone was approved by the FDA in 1960. It belongs to a class of medications known as diuretics. Chlorthalidone is used alone or in combination with other medications in the treatment of high blood pressure. It is also used as adjunctive therapy for fluid retention (edema) caused by congestive heart failure, renal disease, liver cirrhosis, estrogen therapy and corticosteroid therapy. This medication works by increasing the excretion of water from the body. Chlorthalidone has been found to cause potassium loss from the body as well as increase levels of uric acid. Chlorthalidone is a long-acting thiazide derivative with low toxicity.

Dosage and Form

Chlorthalidone comes in tablet form in 25mg and 50mg strengths.

When using chlorthalidone as therapy for hypertension, most patients should be initiated with a single daily dose of 25 mg. If the response is insufficient after a suitable trial, the dosage may be increased to a single daily dose of 50 mg. If additional control is required, the dosage of Chlorthalidone may be increased further to 100 mg once daily or a second antihypertensive drug may be added. Dosage above 100 mg daily usually does not increase effectiveness.

Before Taking Chlorthalidone

Before taking Chlorthalidone make sure your doctor or pharmacist knows:

  • if you are pregnant, trying for a baby or breast-feeding
  • if you suffer from liver or kidney problems
  • if you suffer from Addison's disease, diabetes, gout, porphyria (a blood disorder) or systemic lupus erythematosus (SLE)
  • if you suffer from prostate problems or have problems urinating (passing water)
  • if you have ever had an allergic reaction to this or any other medicine
  • if you are taking any other medicines, including those available to buy without a prescription, herbal and complementary medicines
  • if you have any other medical conditions

Side Effects

The following side effects are the most common side effects associated with chlorthalidone use. Talk to your doctor if any of these conditions persist or become bothersome while taking chlorthalidone:
  • Dizziness
  • Constipation
  • Headache
  • Lightheadedness
While the following side effects are less common, they may be severe. Seek medical attention right away if you experience any of these symptoms while taking chlorthalidone:
  • Severe allergic reaction
  • Drowsiness
  • Dry mouth
  • Impotence
  • Muscle pain or cramps
  • Nausea
  • Rapid or irregular heart beat
  • Restlessness
  • Unusual thirst
  • Unusual tiredness or weakness
  • Vomiting
  • Yellowing of the skin or eyes

Who Should Not Take Chlorthalidone?

Chlorthalidone should not be taken by anyone who:

  • has an allergy to any of the ingredients of this medication or to sulfa drugs
  • has low blood potassium that does not get better with supplementation
  • has increased potassium loss
  • has low sodium in the blood
  • has high levels of calcium in the blood
  • has high uric acid in the blood causing gout
  • is unable to produce urine