Hydrochlorothiazide

It inhibits the active reabsorption of sodium, chiefly in the distal renal tubule, thus increasing the excretion of sodium, chloride & water. Cardiac output and both extracellular & plasma volume decrease and during longterm treatment peripheral vascular resistance diminishes. Combined treatment with other drugs used for the treatment of hypertension potentiates the blood pressure lowering effect.

Indications

Hypertension, heart failure, oedema due to heart falure, mild to moderate renal or hepatic failure. Renal diabetes insipidus. Idopathic hypercalciuria.

Dosage

Hypertension: 25-50 mg 1-2 imes. Heart failure & oedema : 25-75 mg daily in 1-2 doses. Children: 2 mg/kg/day. Renal diabetes insipidus: Initially 100 mg daily in 2-4 doses.

Contra-Indications

Anuria, severe renal & hepatic failure, hypersensitivity, refractory hypokalaemia & hyponatraemia, hypercalcaemia & symptomatic hyperuricaemia.

Special Precautions

nervousness, muscle spasms, cardiac arrhythmias, serum electrolyte balance, diabetes. Paediatrics: Usually not prescribed. Pregnancy: Contraindicated in case of toxaemia of pregnancy. Lactations: The drug passes into breast milk. Elderly: Increased likelihood of adverse effects.

Side Effects

Reduced glucose tolerance, hyper- uricaemia, hypokalaemia.

Drug Interactions

Potentiates anti-hypertensives, caution in patient taking digoxin, increased risk of hypokalemia with corticosteroids, dose of oral antidiabetic agents may need to be raised, probenecid competitively inhibits tubular secretion.