Hypothiazide

Hypothiazide, also known by its chemical name hydrochlorothiazide, is a diuretic drug that belongs to the class of thiazide diuretics. This drug is widely used to treat high blood pressure (hypertension) and swelling associated with heart failure, cirrhosis of the liver, or kidney disease.

Hydrochlorothiazide works by increasing urine output, which helps the body get rid of excess salt and water. It does this by blocking the reabsorption of sodium and chloride in the distal tubules of the kidneys, which leads to an increase in urine volume and, consequently, a decrease in the volume of fluid in the vessels.

Indications Hypothiazide

1. Hypertension (high blood pressure): Hydrochlorothiazide is often prescribed alone or in combination with other antihypertensive drugs to lower blood pressure.
2. Edema associated with heart failure: The drug helps reduce fluid accumulation in the body by increasing the excretion of sodium and water through the kidneys, which may relieve swelling associated with heart failure.
3. Swelling caused by liver disease or kidney failure: Hydrochlorothiazide may be prescribed to reduce swelling that occurs when liver or kidney function is impaired.
4. Nephrogenic diabetic nephropathy: In some cases, hydrochlorothiazide may be used to manage diabetic nephropathy (kidney damage caused by diabetes).

Release form

Hypothiazide (hydrochlorothiazide) usually comes as a tablet to take by mouth.

Pharmacodynamics

The mechanism of action of hydrochlorothiazide is its ability to increase the excretion of sodium and chloride from the body by inhibiting the reabsorption of these ions in the kidneys. This leads to a decrease in the volume of circulating blood and a decrease in the volume of fluid in the vascular bed. A decrease in the volume of circulating blood leads to a decrease in blood volume, which in turn reduces blood pressure.

In addition, hydrochlorothiazide may also increase the sensitivity of blood vessels to vasoconstrictor substances such as adrenaline, which also helps to lower blood pressure.

Pharmacokinetics

1. Absorption: Hydrochlorothiazide is generally rapidly and completely absorbed from the gastrointestinal tract after oral administration.
2. Metabolism: Hydrochlorothiazide is metabolized in the liver, primarily through conjugation with glucuronic acid.
3. Elimination: Hydrochlorothiazide and its metabolites are excreted primarily by the kidneys. The majority of the dose is excreted unchanged within the first 24 hours after administration.
4. Half-life: The half-life of hydrochlorothiazide is about 5-15 hours. This means that the drug levels in the body are reduced by about half in about this time.
5. Chronic effect: With regular administration of hydrochlorothiazide, its diuretic effect may persist for a long time even after a single dose due to accumulation in tissues.
6. Side effects: As with any drug, hydrochlorothiazide has side effects, including electrolyte disturbances (such as hypokalemia), hyperuricemia, hyperglycemia, hyponatremia, and fluid imbalance.
7. Individual variability: Pharmacokinetics may be altered in patients with renal or hepatic impairment.

Dosing and administration

1. Dosage:

   • The usual starting dose for adults is usually 12.5 mg per day.
   • The dosage may be increased to 25-50 mg per day if necessary.
   • For children, the dosage is determined depending on weight and is usually 0.5-2 mg per kilogram of body weight per day, divided into several doses.

2. Directions for use:

   • Hydrochlorothiazide is usually taken by mouth by swallowing the tablet whole with water.
   • It can be taken either with or without food.
   • Take at the same time every day to maintain a stable level of the drug in the body.

3. Notes:

   • It is important to follow the recommended dosage and instructions for the drug.
   • Before changing the dosage or schedule of hydrochlorothiazide, you should consult your doctor.
   • Do not exceed the recommended dosage without consulting your doctor.

Use Hypothiazide during pregnancy

1. Effect on the fetus:

   • Hydrochlorothiazide is in the FDA pregnancy category B. This means that animal studies have shown no risk to the fetus, but controlled studies have not been conducted in pregnant women.
   • There is a theoretical risk that thiazides, including hydrochlorothiazide, may affect fluid and electrolyte balance, which could affect the fetus.

2. Effects on pregnancy:

   • Thiazides may decrease plasma volume, potentially leading to decreased placental perfusion and, consequently, fetal growth restriction and other complications.

3. Recommendations:

   • It is generally recommended to avoid the use of hydrochlorothiazide during pregnancy, especially in the second and third trimesters, due to potential risks and limited safety information.
   • If treatment for high blood pressure during pregnancy is necessary, it is better to use alternative medications known to be safe in pregnancy, such as methyldopa or nifedipine.

Contraindications

1. Known allergy or intolerance: People with a known allergy to hydrochlorothiazide or other thiazide diuretics should avoid its use.
2. Hyperkalemia: Hydrochlorothiazide may cause an increase in blood potassium levels, so its use may be contraindicated in patients with hyperkalemia.
3. Hyponatremia: Treatment with hydrochlorothiazide may result in a decrease in blood sodium levels, so it should be used with caution in patients with hyponatremia.
4. Renal impairment: In patients with renal impairment, particularly severe renal impairment, hydrochlorothiazide may impair renal function and is contraindicated.
5. Hypercalcemia: If hypercalcemia (increased calcium levels in the blood) is present, hydrochlorothiazide may be contraindicated.
6. Decompensated heart failure: Hydrochlorothiazide may worsen decompensated heart failure.
7. Pregnancy and breastfeeding: Use of hydrochlorothiazide during pregnancy and breastfeeding may be contraindicated. Use should be carried out only under strict medical indications and under the supervision of a physician.

Side effects Hypothiazide

1. Dehydration: Hydrochlorothiazide can cause significant loss of fluid and electrolytes through the kidneys, which can cause dehydration.
2. Hypokalemia: This medication may lower the level of potassium in the blood, which can lead to muscle weakness, tiredness, irregular heartbeat, and other symptoms.
3. Hyponatremia: Hydrochlorothiazide can cause low sodium levels in the blood, which can lead to headache, drowsiness, muscle cramps, and other symptoms.
4. Hyperuricemia: Increased levels of uric acid in the blood, which can worsen gout or lead to the formation of urinary stones.
5. Hyperglycemia: Hydrochlorothiazide can raise blood glucose levels, which can be problematic for people with diabetes.
6. Hypercalcemia: Increased levels of calcium in the blood, which can lead to fatigue, nausea, vomiting, constipation, and other symptoms.
7. Hyperlipidemia: Increased levels of lipids in the blood, including cholesterol and triglycerides.
8. Hyperurinemia: Increased levels of urea in the blood, which may be an indicator of impaired kidney function.

Overdose

1. Severe dehydration: Because hydrochlorothiazide increases the loss of fluid from the body, taking too much of the drug can lead to significant fluid loss and dehydration. This can manifest as dry skin and mucous membranes, decreased urine output, weakness, cramps, and even decreased blood pressure.
2. Electrolyte disturbances: Overdose can cause low blood levels of potassium (hypokalemia), sodium (hyponatremia), magnesium (hypomagnesemia), and other electrolytes, which can lead to abnormal heart rhythms, muscle cramps, fatigue, and even organ damage.
3. High blood pressure: The intense diuretic action of hydrochlorothiazide can cause a sharp decrease in blood pressure (hypotension), which in turn can lead to dizziness, orthostatic reactions and, in rare cases, fainting.
4. Renal failure: Overdose of hydrochlorothiazide may lead to acute renal failure due to its diuretic effect, which may require urgent medical intervention.

Interactions with other drugs

1. Medicines that increase potassium levels: Hydrochlorothiazide may increase potassium loss, so concomitant use with other medicines that may also decrease blood potassium levels (eg, digoxin, lithium, certain diuretics, amphotericin B) may result in hypokalemia.
2. Antihypertensive drugs: Combination of hydrochlorothiazide with other antihypertensive drugs such as calcium channel blockers, angiotensin-converting enzyme inhibitors (ACE inhibitors) or aldosterone antagonists may result in additional reduction in blood pressure.
3. Heart failure medications: Using hydrochlorothiazide with medications used to treat heart failure, such as digoxin or angiotensin-converting enzyme inhibitors (ACE inhibitors), may increase their effect.
4. Nephrotoxic drugs: Hydrochlorothiazide may enhance the nephrotoxicity of drugs such as some nonsteroidal anti-inflammatory drugs (NSAIDs) or aminoglycoside class antibiotics.
5. Medicines that increase blood urea levels: Hydrochlorothiazide may increase blood urea levels when combined with medications that can also increase blood urea levels, such as certain nonsteroidal anti-inflammatory drugs (NSAIDs).