Chlorthalidone is a thiazide diuretic (water pill) that helps prevent your body from absorbing too much salt, which can cause fluid retention.Over time it also relaxes blood vessels and improves blood flow.

• Chlorthalidone treats fluid retention (edema) in people with congestive heart failure, cirrhosis of the liver, or kidney disorders, or edema caused by taking steroids or estrogen.
• Chlorthalidone is also used to treat high blood pressure (hypertension).

• Headache,
• Nausea,
• Increased blood uric acid,
• Decreased potassium level in blood,
• Glucose intolerance,
• Altered blood lipid level

• You should not use chlorthalidone if you are unable to urinate, or if you are allergic to sulfa drugs.
• It makes you feel dizzy. Avoid driving and attention requiring activity until you know how it affects you.
• Avoid alcohol intake while taking Chlorthalidone as it may increase the dizziness. 
• It may cause a sudden drop of sodium level in blood. Avoid low sodium diet while you are taking this medication.