Drug information of Hydrochlorothiazide

Hydrochlorothiazide


HCTZ (hydrochlorothiazide) is a thiazide diuretic (water pill) that helps prevent your body from absorbing too much salt, which can cause fluid retention. HCTZ 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. This medication is also used to treat high blood pressure (hypertension).

Mechanism of effect

Hydrochlorothiazide affects the distal renal tubular mechanism of electrolyte reabsorption. At maximal therapeutic dosage all thiazides are approximately equal in their diuretic efï¬cacy. Hydrochlorothiazide increases excretion of sodium and chloride in approximately equivalent amounts. Natriuresis may be accompanied by some loss of potassium and bicarbonate.

Pharmacodynamic

Thiazides such as hydrochlorothiazide promote water loss from the body (diuretics). They inhibit Na+/Cl- reabsorption from the distal convoluted tubules in the kidneys. Thiazides also cause loss of potassium and an increase in serum uric acid

Pharmacokinetics

Absorption:50-60% Protein binding:67.9% Hydrochlorothiazide is not metabolized but is eliminated rapidly by the kidney. the plasma half-life has been observed to vary between 5.6 and 14.8 hours. At least 61% of the oral dose is eliminated unchanged within 24 hours. Hydrochlorothiazide crosses the placental but not the blood-brain barrier and is excreted in breast milk.

Dosage

Usual Adult Dose for Edema
Usual dose: 25 mg to 100 mg orally once or twice daily
Usual Adult Dose for Hypertension
Initial dose: 25 mg orally once daily
Maintenance dose: May increase to 50 mg orally daily, as a single or 2 divided doses
Usual Pediatric Dose for Edema
Less than 6 months: Up to 3 mg/kg/day (up to 1.5 mg/pound) orally in 2 divided doses
Less than 2 years: 1 to 2 mg/kg/day (0.5 to 1 mg/pound) orally daily as a single dose or in 2 divided doses
Maximum dose 37.5 mg per day
2 to 12 years: 1 to 2 mg/kg/day (0.5 to 1 mg/pound) orally daily as a single dose or in 2 divided doses
Maximum dose 100 mg per day
Usual Pediatric Dose for Hypertension
Less than 6 months: Up to 3 mg/kg/day (up to 1.5 mg/pound) orally in 2 divided doses
Less than 2 years: 1 to 2 mg/kg/day (0.5 to 1 mg/pound) orally daily as a single dose or in 2 divided doses
Maximum dose 37.5 mg per day
2 to 12 years: 1 to 2 mg/kg/day (0.5 to 1 mg/pound) orally daily as a single dose or in 2 divided doses
Maximum dose 100 mg per day

Alerts

1-Use with caution in severe renal disease.
2-Thiazides should be used with caution in patients with impaired hepatic function or progressive liver disease, since minor alterations of fluid and electrolyte balance may precipitate hepatic coma.

Points of recommendation

1-The antihypertensive effects of the drug may be enhanced in the post-sympathectomy patient.
2-Avoid excess salt/sodium unless otherwise instructed by your physician.
3-Avoid alcohol.
4-Do not take calcium, aluminum, magnesium or Iron supplements within 2 hours of taking this medication.
5-Increase potassium intake; add a banana or orange juice; unless instructed otherwise.
6-Take with food.

Pregnancy level

B


Ask a Pharmacist


User's questions
    No comments yet.