Hydrochlorothiazide

BRAND NAMES:

Aquazide 12.5: This tablet is a diuretic containing hydrochlorothiazide (12.5 mg), which is prescribed to treat hypertension. This medication lowers excess fluid levels in the body and treats edema (fluid overload) caused by heart, liver, kidney, or lung disorders.

Telvis H: This tablet combines two medications (telmisartan 40 mg and hydrochlorothiazide 12.5 mg) that help regulate high blood pressure. It is typically used when one medication fails to regulate blood pressure adequately. Lowering blood pressure reduces your chance of having a heart attack or stroke in the future.

Niavas D 5/12.5: The Niavas D 5 mg/12.5 mg medication, which includes Nebivolol 5 mg and hydrochlorothiazide 12.5 mg, prevents numerous chemicals from affecting your heart and blood vessels.

Rigard H 50/12.5: In this Losartan potassium and hydrochlorothiazide are the main ingradients. These are available in the markets with combinational strengths of 50 mg of losartan potassium and 12.5 mg of hydrochlorothiazide film-coated tablets.

MECHANISM OF ACTION:

Hydrochlorothiazide directly inhibits the sodium chloride cotransporter, which is found on the apical membrane of the kidney's distal convoluted tubule. The distal convoluted tubule is responsible for reabsorbing about 5% to 10% of the sodium in the kidney. This inhibition raises the concentration of sodium that travels to the collecting ducts by inhibiting sodium resorption in the distal convoluted tubules. Hydrochlorothiazide inhibits sodium-potassium ATPase pump function on the basolateral surface by preventing sodium from entering the tubular lumen. This action inhibits the flow of salt and water into the interstitial region. The increasing concentration of positively charged sodium ions traveling through the distal convoluted tubule creates an ionic imbalance, further opening the voltage-gated channels. This transient receptor potential stimulates calcium reabsorption from the tubular lumen, facilitated over the basolateral surface by the calcium ATPase pump and sodium-calcium exchanger. Calcium reabsorption in the distal convoluted tubules provides for 7–10% of total filtered calcium retention. Aldosterone, a mineralocorticoid, regulates sodium reabsorption and potassium excretion in the kidney's collecting ducts. Elevated sodium concentrations in the collecting duct cause aldosterone to bind to the mineralocorticoid receptor, triggering the transcription of ion transport protein channels. This causes sodium reabsorption via epithelial sodium channels in the main cells and potassium excretion in the intercalated cells, resulting in natriuresis and diuresis effects.

PHARMACOKINETICS:

Absorption: Hydrochlorothiazide has an oral bioavailability of 65-75%, a Tmax of 1-4 hours, and a Cmax of 70-490 ng/mL for dosages ranging from 12.5 to 100 mg. When taken with a meal, bioavailability decreases by 10%, Cmax decreases by 20%, and Tmax rises from 1.6 to 2.9 hours.

Distribution: The volume of distribution varies substantially from one study to another, with estimates ranging from 0.83 to 4.19 L/kg.

Elimination: Hydrochlorothiazide is 40–68% protein bound in plasma. Hydrochlorothiazide has been reported to bind with human serum albumin.

PHARMACODYNAMICS:

Hydrochlorothiazide reduces sodium and water reabsorption from the distal convoluted tubule, allowing more water to be eliminated in urine. Hydrochlorothiazide has a broad therapeutic window because the dose is personalized and might range from 25 to 100 mg. Hydrochlorothiazide should be used with caution in patients with decreased renal or hepatic function.

DOSAGE AND ADMINISTRATION:

The dosage of hydrochlorothiazide for the treatment of chronic hypertension is 12.5 to 25 mg daily, followed by titration to a maximum daily dosage of 50 mg once daily after 2 to 4 weeks. In the treatment of peripheral edema, an initial beginning dose of 25 to 50 mg may be administered once or twice a day, with a maximum daily dose of 200 mg. Polyuria in nephrogenic diabetic insipidus can be treated with hydrochlorothiazide, starting with a dosage of 25 mg twice daily. To avoid calcium nephrolithiasis, the suggested starting dose of hydrochlorothiazide is 25 mg daily. The dosage can be modified to one or two doses each day, with a maximum recommended daily intake of 50 or 100 mg. Untreated hypertension causes unfavorable cardiovascular remodeling and increases the risk of major adverse cardiac events. Antihypertensive therapy should be customized to the patient's unique needs, taking into account any coexisting conditions. The 2017 hypertension management guidelines recommend thiazide-type diuretics, calcium channel blockers, or RAS inhibitors as first-line medications. Hydrochlorothiazide is not the first line of treatment for those with chronic kidney disease, diabetes, coronary artery disease, or congestive heart failure.

CONTRAINDICATIONS:

Hydrochlorothiazide is not recommended if you have anuria or have a sulfonamide allergy. This medicine should be taken with caution in individuals with severe hepatic impairment since it has the potential to cause hepatic coma. Individuals with underlying adrenal insufficiency should avoid hydrochlorothiazide treatment.

DRUG INTERACTIONS:

Abacavir excretion rate may be slowed by hydrochlorothiazide, thereby raising serum levels. Hydrochlorothiazide and Abaloparatide together may enhance the likelihood or intensity of side effects. When taken with hydrochlorothiazide, acarbose's therapeutic efficacy may be lowered.

FOOD INTERACTIONS:

• Avoid alcohol. Alcohol may increase orthostatic hypotension.
• Avoid multivalent ions. To minimize decreased hydrochlorothiazide absorption, take this drug 2 hours before or after administering antacids, calcium supplements, or iron supplements.
• Avoid natural liquorice. Licorice increases the hypokalemic impact of hydrochlorothiazide.
• Increase your diet of potassium-rich foods. This medicine may deplete potassium. Potassium-rich foods include bananas and orange juice.
• Limit your salt intake. Excessive salt should be avoided unless suggested by a doctor. 
• Consume with or without food.

SIDE EFFECTS:

The common side effects include

Low blood pressure with worsening kidney function

Electrolyte changes and increases blood level

Short-sightedness and Glaucoma

Severe allergic reactions

Severe skin reactions

Inflammation in pancreas

Liver damage

Low blood pressure with worsening kidney function:

Hydrochlorothiazide's water loss might cause dehydration and excessive blood pressure reduction. Both may cause more serious complications than lightheadedness. Poor blood flow to vital organs like your kidneys might occur, especially if you are elderly. symptoms, which include

• Dizziness, feeling lightheaded or fainting
• Confusion
• Feeling tired or weak
• Sudden weight gain
• Reduced need to pee
• Increased thirst

TOXICITY:

Hydrochlorothiazide diuretics may increase photosensitivity and lower the threshold for UV-induced phototoxicity. Patients who have overdosed may have hypokalemia, hypochloremia, or hyponatremia. Treat patients with symptomatic and supportive care, including fluids and electrolytes. To treat hypotension, vasopressors may be used, and oxygen may be supplied if respiratory impairment exists.

STORAGE CONDITIONS:

Store hydrochlorothiazide between 68°F and 77°F (20°C and 25°C). Keep this medicine away from light.