Chlorthalidone is indicated for the following conditions-

• Hypertension
• Edema associated with congestive heart failure, renal dysfunction hepatic cirrhosis, and corticosteroid and estrogen therapy.

Hypertension (Hight Blood Pressure)

Edema

• Chlorthalidone Tablets USP 15 mg and 25 mg tablets are for oral administration.
• Chlorthalidone cannot be substituted with other formulations of chlorthalidone.
• Therapy should be initiated with the lowest possible dose, then titrated according to individual patient response. A single dose given in the morning with food is recommended; divided doses are unnecessary.

The following adverse reactions have been observed, but there is not enough systematic collection of data to support an estimate of their frequency.

• Gastrointestinal System Reactions: anorexia, gastric irritation, nausea, vomiting, cramping, diarrhea, constipation, jaundice (intrahepatic cholestatic jaundice), pancreatitis.
• Central Nervous System Reactions: dizziness, vertigo, paresthesia, headache, xanthopsia.
• Hematologic Reactions: leukopenia, agranulocytosis, thrombocytopenia, aplastic anemia.
• Dermatologic-Hypersensitivity Reactions: purpura, photosensitivity, rash, urticaria, necrotizing angiitis (vasculitis) (cutaneous vasculitis), Lyell’s syndrome (toxic epidermal necrolysis).
• Cardiovascular Reaction: Orthostatic hypotension may occur and may be aggravated by alcohol, barbiturates or narcotics.
• Other Adverse Reactions: hyperglycemia, glycosuria, hyperuricemia, muscle spasm, weakness, restlessness, impotence. 

Anorexia	Vomiting	Dizziness
Leukopenia	Rash	Purpura

• Hypokalemia and other electrolyte abnormalities, including hyponatremia and hypochloremic alkalosis, are common in patients receiving chlorthalidone. These abnormalities are dose-related but may occur even at the lowest marketed doses of chlorthalidone.
• Thiazide-like diuretics have been shown to increase the urinary excretion of magnesium; this may result in hypomagnesemia.
• Calcium excretion is decreased by thiazide-like drugs. Pathological changes in the parathyroid gland with hypercalcemia and hypophosphatemia have been observed in a few patients on thiazide therapy. 
• Hyperuricemia may occur or frank gout may be precipitated in certain patients receiving chlorthalidone. 
• Increases in serum glucose may occur and latent diabetes mellitus may become manifest during chlorthalidone therapy. Chlorthalidone and related drugs may decrease serum PBI levels without signs of thyroid disturbance.