Chlorthalidone

Chlorthalidone is a diuretic (water pill) medicine used to treat hypertension (high blood pressure). This medicine reduces excess fluid levels in the body and treats edema (fluid overload) associated with heart, liver, kidney, or lung disease. Chlorthalidone makes you lose excess water through urine. It may be used alone or in combination with other medicines. This medicine should be taken only during day time to avoid frequent urination at night. You must take this medicine in the dose and duration as advised by the doctor and never stop it abruptly without consulting the doctor. Most people with high blood pressure do not feel ill, but if you stop taking this medicine, your condition could get worse. This may lead to your blood pressure rising up again and increase your risk of heart disease and stroke. It is important to have your blood pressure checked regularly. This medicine is only one part of a treatment program which should also include a healthy diet, regular exercise, smoking cessation, moderation of alcohol intake and weight reduction.

Chlorthalidone is a diuretic which lowers blood pressure by removing extra water and certain electrolytes from the body. Over time it also relaxes blood vessels and improves blood flow.

• Hypertension (high blood pressure)
• Edema - associated with congestive heart failure, hepatic cirrhosis, corticosteroid and estrogen therapy
• Mild to moderate renal disease

Chlorthalidone is a thiazide-type Diuretic-Antihypertensive, used for the treatment of hypertension. It may be used alone or in association with other antihypertensive agents. Chlorthalidone inhibits the reabsorption of sodium and chloride in the distal renal tubule thus promoting water loss. The higher urine volume increases potassium loss. The blood pressure lowering effects are initially due to volume reduction but the persisting effect includes other undetermined mechanisms that reduce peripheral resistance.

Chlorthalidone enhances the excretion of sodium, chloride and water by interfering with the transport of sodium ions across the renal tubular epithelium. Its primary site of action appears to be at the cortical diluting segment in the nephron of the loop of Henle.

Adult Dose:

Renal Dose: CrCl ≥10 mL/min: No dose adjustment needed. CrCl <30 mL/min: Loop diuretics may be more appropriate.

Elderly: 50 mg/day or less (to avoid hypovolemia and hypokalemia).

Take this medicine in the dose and duration as advised by your doctor. Swallow it as a whole. Do not chew, crush or break it. Chlorthalidone is to be taken with food. Take it in the morning with breakfast to avoid getting up at night to urinate.

If you miss a dose of Chlorthalidone, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular schedule. Do not double the dose.

Common Side Effects:

• Headache
• Nausea
• Increased blood uric acid
• Decreased potassium level
• Glucose intolerance
• Altered blood lipid level
• Dizziness
• Orthostatic hypotension

Serious Side Effects: Hypokalemia, hyponatremia, hypomagnesemia, hyperglycemia, hypercalcemia, glycosuria, gout, cholestatic jaundice, cardiac arrhythmias.

• [UNSAFE] Chlorthalidone may decrease alertness, affect your vision or make you feel sleepy and dizzy. Do not drive if these symptoms occur.
• Take it in the morning with breakfast.
• Avoid alcohol intake as it may increase dizziness.
• Monitor potassium levels.
• Caution during pregnancy and lactation.
• Consult your doctor if you have liver or kidney disease.

• Severe renal impairment or anuria (CrCl <30 mL/min)
• Severe hepatic impairment
• Addison's disease
• Preexisting hypercalcemia
• Asthma
• Hypersensitivity
• Severe allergy
• Pregnancy and lactation

NSAIDs antagonise hypotensive action. Suppresses action of oral anticoagulants. Increased risk of hypokalemia with corticosteroids. Potentiates bone marrow suppression caused by anticancer drugs. Aminoglycoside nephrotoxicity potentiated. Impairs action of oral hypoglycemic agents. Enhances digitalis toxicity due to hypokalemia. Lithium toxicity enhanced.

Interactions with antihypertensives, digitalis, corticosteroids, NSAIDs, allopurinol, amantadine, cyclosporin, vitamin D, calcium salts, diazoxide.

[UNSAFE] Chlorthalidone may cause excessive drowsiness with alcohol.

[CONSULT YOUR DOCTOR] Chlorthalidone may be unsafe to use during pregnancy. Can cause placental hypoperfusion. Should not be used to treat hypertension in pregnant women. Avoid particularly during the first trimester.

[SAFE IF PRESCRIBED] Chlorthalidone is safe to use during breastfeeding. Human studies suggest that the drug does not pass into the breastmilk in a significant amount and is not harmful to the baby. Chlorthalidone appears in breast milk (approximately 4% of maternal blood levels). Use in nursing mothers should be avoided.

Limited information is available regarding safety and efficacy in pediatric patients.

Suitable drug for treating hypertension in the elderly, in particular systolic hypertension. Dose of 50 mg daily or less should be used to avoid hypovolemia and hypokalemia.

[CAUTION] Chlorthalidone should be used with caution in patients with severe kidney disease. Dose adjustment of Chlorthalidone may be needed. Please consult your doctor. Dosage should be reduced in moderate renal failure (every 24 or 48 h) and should not be used in advanced renal failure.

[CAUTION] Chlorthalidone should be used with caution in patients with liver disease. Please consult your doctor. Risk of precipitating hepatic encephalopathy in patients with liver cirrhosis and ascites.

Acute overdose symptoms include nausea, weakness, dizziness, and electrolyte imbalance. No specific antidote. Gastric lavage recommended, followed by supportive treatment. May include intravenous dextrose-saline with potassium, administered with caution.

Keep below 30°C temperature, away from light & moisture. Keep out of the reach of children.

Chlorthalidone