Hydrochlorothiazide

(hye droe klor oh thye' a zide)

PCI - Contraindicated in pregnancy

LCI - Contraindicated in lactation

Molecule Info

 
Indication(s) & Dosage

Hydrochlorothiazide tablets are indicated as adjunctive therapy in edema associated with congestive heart failure, hepatic cirrhosis, and corticosteroid and estrogen therapy. Hydrochlorothiazide tablets have also been found useful in edema due to various forms of renal dysfunction such as nephrotic syndrome, acute glomerulonephritis, and chronic renal failure. Hydrochlorothiazide tablets are indicated in the management of hypertension either as the sole therapeutic agent or to enhance the effectiveness of other antihypertensive drugs in the more severe forms of hypertension.

HYPERTENSION
Adult: Initially, 12.5 mg orally daily. Usual dose: 25-50 mg daily, either alone or combined with other antihypertensives, up to 100 mg daily, if necessary.

CrCl (ml/min) Dosage Recommendation
<10 Avoid.

Oedema associated with heart failure
Adult: Usual dosage: 25-100 mg orally daily in the morning, may reduce to 25-50 mg daily or intermittently. Up to 200 mg daily may be used as initial doses in severe cases.
CrCl (ml/min) Dosage Recommendation
<10 Avoid.

Nephrogenic diabetes insipidus
Adult: Initial dose: Up to 100 mg orally daily.
Child: Initially, 1-2 mg/kg/day in 1-2 divided doses; <6 mth: up to 3 mg/kg/day.
CrCl (ml/min) Dosage Recommendation
<10 Avoid.
Administration Should be taken on an empty stomach. Take 15-30 min before meals.
Overdosage Lethargy, nausea, weakness and electrolyte imbalance, possibly progress to coma within a few hr with minimal depression of respiratory and CV function and with no evidence of dehydration or serum electrolyte changes. GI irritation and hypermotility, temporary elevation of the BUN, serum electrolyte changes (e.g., hypokalemia, hypochloremia, hyponatremia) may occur in renally impaired patients. Empty stomach by inducing vomiting with ipecac syrup If patient is conscious. Cathartics should not be admin as they may promote loss of fluid and electrolytes. Supportive and symptomatic treatment with monitoring of serum electrolytes, renal, respiratory, and CV function. Replace fluid and electrolytes where necessary.
Contraindications Severe hepatic and renal impairment, Addison's disease, preexisting hypercalcaemia, anuria, sulphonamide allergy. Pregnancy, lactation.
Special Precautions Existing electrolyte disturbances, hepatic cirrhosis, severe heart failure, oedema, elderly, renal impairment. Monitor for signs of fluid and electrolyte disturbance. Hepatic impairment, DM, gout, hyperlipidaemia, hypercalcaemia, hyperuricaemia; ECG: LVH and/or ventricular ectopics (extrasystoles). May exacerbate or activate SLE in susceptible patients.
Adverse Drug Reaction(s) Volume depletion and electrolyte imbalance, dry mouth, thirst, lethargy, drowsiness, muscle pain and cramps, hypotension, hypersensitivity reactions e.g. rashes, photosensitivity, thrombocytopenia, jaundice, pancreatitis; fatigue, weakness; may precipitate an attack of gout; impotence, hyperglycaemia; anorexia, gastric irritation, nausea, vomiting, constipation, diarrhoea, sialadenitis, dizziness, raised Ca concentration.
Potentially Fatal: Hypersensitivity reactions.
Drug Interactions May cause hyponatraemia when used with carbamazepine. May increase risk of toxicity when used with allopurinol or tetracyclines. Potentiates hypotensive effect of α-blockers and ACE inhibitors. Diuretic-induced hypokalaemia may increase the toxicity of digitalis glycosides and risk of arrhythmias when used with drugs that prolong QT interval. May increase serum concentrations of lithium when used together. Concurrent use with alcohol, barbiturates and opioids may enhance diuretic-enhanced orthostatic hypotension. Antihypertensive effect may be reduced by corticosteroids, NSAIDs or carbenoxolone. May enhance the nephrotoxicity of NSAIDs.
Potentially Fatal: Enhances neuromuscular blocking action of competitive muscle relaxants. Impaired control of diabetes by oral hypoglycaemic agents.

Usage in Pregnancy

Usage in Pregnancy: 

Routine use of diuretics during normal pregnancy is inappropriate and exposes mother and fetus to unnecessary hazard. Diuretics do not prevent development of toxemia of pregnancy and there is no satisfactory evidence that they are useful in the treatment of toxemia.

Edema during pregnancy may arise from pathologic causes or from the physiologic and mechanical consequences of pregnancy. Thiazides are indicated in pregnancy when edema is due to pathologic causes, just as they are in the absence of pregnancy. Dependent edema in pregnancy, resulting from restriction of venous return by the gravid uterus, is properly treated through elevation of the lower extremities and use of support stockings. Use of diuretics to lower intravascular volume in this instance is illogical and unnecessary. During normal pregnancy there is hypervolemia which is not harmful to the fetus or the mother in the absence of cardiovascular disease. However, it may be associated with edema, rarely generalized edema. If such edema causes discomfort, increased recumbency will often provide relief. Rarely this edema may cause extreme discomfort which is not relieved by rest. In these instances, a short course of diuretic therapy may provide relief and be appropriate.

Category D: If used in pregnancy-induced HTN.There is positive evidence of human foetal risk, but the benefits from use in pregnant women may be acceptable despite the risk (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective).

Storage Oral: Store at 15-30°C.
Pharmacology

Hydrochlorothiazide blocks the reabsorption of sodium and chloride ions, and thereby increases the quantity of sodium traversing the distal tubule and the volume of water excreted. A portion of the additional sodium presented to the distal tubule is exchanged there for potassium and hydrogen ions. With continued use of hydrochlorothiazide and depletion of sodium, compensatory mechanisms tend to increase this exchange and may produce excessive loss of potassium, hydrogen, and chloride ions. Hydrochlorothiazide also decreases the excretion of calcium and uric acid, may increase the excretion of iodide, and may reduce glomerular filtration rate. The exact mechanism of the antihypertensive effect of hydrochlorothiazide is not known.

Hydrochlorothiazide inhibits the reabsorption of Na and chloride at the beginning of the distal convoluted tubule. It causes natriuretic effect mainly by decreasing Na and chloride reabsorption in the cortical segment of the ascending limb of the loop of Henle by inhibition of a specific Na+Cl- co-transporter.

Onset: 2 hr (oral).
Duration: 6-12 hr (oral).
Absorption: Fairly absorbed from the GI tract; peak plasma concentrations after 4 hr (oral).
Distribution: Crosses the placenta; enters the breast milk; bound to RBCs.
Excretion: Urine (as unchanged drug); 5-15 hr (elimination half-life).

ATC Classification C03AA03 - hydrochlorothiazide; Belongs to the class of low-ceiling thiazide diuretics. Used to promote excretion of urine.

 

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Brand/Product Info


Total Products : 4    
Brand Name Manufacturer/Marketer Composition Dosage Form Pack Size & Price
Acuren 25 Incepta Pharmaceuticals Limited Hydrochlorothiazide BP 50mg Tablet 10x10's:MRP 70 Tk
Acuren 50 Incepta Pharmaceuticals Limited Hydrochlorothiazide BP 25mg Tablet 10x10's:MRP 100 Tk
HTZ Unimed & Unihealth Manufacturers Ltd. Hydrochlorothiazide BP 25mg Tablet 25mg x 100's: 70.00 MRP
HYPEZIDE Pacific Pharmaceuticals Ltd. Hydrochlorothiazide BP 50mg Tablet 50mg x 100's: 100.00 MRP

Gen. MedInfo

Why is this medication prescribed?

Hydrochlorothiazide, a 'water pill,' is used to treat high blood pressure and fluid retention caused by various conditions, including heart disease. It causes the kidneys to get rid of unneeded water and salt from the body into the urine. This medicine is sometimes prescribed for other uses; ask your doctor for more information.

How should this medicine be used?

Hydrochlorothiazide comes as a tablet and liquid to take by mouth. It usually is taken once or twice a day. If you are to take it once a day, take it in the morning; if you are to take it twice a day, take it in the morning and in the late afternoon to avoid going to the bathroom during the night. Take this medication with a meal or snack. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take hydrochlorothiazide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Hydrochlorothiazide controls high blood pressure but does not cure it. Continue to take hydrochlorothiazide even if you feel well. Do not stop taking hydrochlorothiazide without talking to your doctor.

Other uses for this medicine

Hydrochlorothiazide may also be used to treat patients with diabetes insipidus and certain electrolyte disturbances and to prevent kidney stones in patients with high levels of calcium in their blood. Talk to your doctor about the possible risks of using this medicine for your condition.

What special precautions should I follow?

Before taking hydrochlorothiazide,
  • tell your doctor and pharmacist if you are allergic to hydrochlorothiazide, sulfa drugs, or any other drugs.
  • tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially other medicines for high blood pressure, anti-inflammatory medications such as ibuprofen or naproxen, corticosteroids, lithium, medications for diabetes, probenecid, and vitamins. If you also are taking cholestyramine or colestipol, take it at least 1 hour after hydrochlorothiazide.
  • tell your doctor if you have or have ever had diabetes, gout, or kidney, liver, thyroid, or parathyroid disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking hydrochlorothiazide, call your doctor immediately.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking hydrochlorothiazide.
  • you should know that this drug may make you drowsy. Do not drive a car or operate machinery until you know how this drug affects you.
  • remember that alcohol can add to the drowsiness caused by this drug.
  • plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Hydrochlorothiazide may make your skin sensitive to sunlight.

What special dietary instructions should I follow?

Follow your doctor's directions. They may include following a daily exercise program or a low-salt or low-sodium diet, potassium supplements, and increased amounts of potassium-rich foods (e.g., bananas, prunes, raisins, and orange juice) in your diet.
 
What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for your next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?

Frequent urination should go away after you take hydrochlorothiazide for a few weeks. Tell your doctor if any of these symptoms are severe or do not go away:
  • muscle weakness

  • dizziness

  • cramps

  • thirst

  • stomach pain

  • nausea

  • vomiting

  • diarrhea

  • loss of appetite

  • headache

  • hair loss

If you experience any of the following symptoms, call your doctor immediately:

  • sore throat with fever

  • unusual bleeding or bruising

  • severe skin rash with peeling skin

  • difficulty breathing or swallowing

Before Calling Emergency

Determine the following information:

  • Patient's age, weight and condition
  • Name of the product/medicine (ingredients and strengths, if possible)
  • Time it was swallowed/taken
  • Amount swallowed/taken

 What to Expect at the Emergency Room

 The Health Care Provider/ Emergency Doctor will measure and monitor the patient's vital signs, including temperature, pulse, breathing rate and blood pressure. Symptoms will be treated as appropriate. The patient may receive:

  • Antidote, gastric lavage, activated charcoal or other drugs/procedures as required
  • Blood tests to determine body chemical levels and blood acid/base balance
  • EKG/ECG test
  • Medicines to correct fluid and electrolyte imbalances

Do not let anyone else take your medicine.  

It is important for you to keep a written list of all of the prescription and nonprescription medicines you are taking, as well as any products such as vitamins, minerals or other dietary supplements.  You should bring this list with you each time you visit a doctor or if you are admitted into a hospital.  It is also important information to carry with you in case of emergencies.

Ref: U.S. Natl. Library of Medicine

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