Diovan

Diovan (valsartan) is a drug that belongs to the class of angiotensin II receptor antagonists, also known as angiotensin II receptor blockers (ARBs). This medication is used to treat high blood pressure (hypertension), heart failure, and other cardiovascular conditions.

Valsartan works by blocking angiotensin II receptors in the vascular system. Angiotensin II is a substance that causes blood vessels to narrow and raise blood pressure. Blocking its action allows the blood vessels to widen, which reduces resistance to blood flow and allows the heart to pump blood more efficiently around the body, reducing pressure in the arteries.

Diovan is usually taken orally in tablet form. The dosage and regimen are determined by the doctor depending on the patient’s condition and his response to treatment. As with any medicine, you should consult your doctor before using Diovan.

Indications Diovana

1. Hypertension (High Blood Pressure): Diovan is used to reduce high blood pressure in patients with hypertension. High blood pressure may be a risk factor for developing cardiovascular diseases such as stroke and heart attacks.
2. Heart failure: Diovan may be prescribed as part of a combination therapy to improve cardiac contractility, reduce symptoms and improve quality of life in patients with heart failure.
3. Post-infarction: Valsartan may be prescribed to patients at high risk of cardiovascular complications after myocardial infarction to prevent recurrent cardiovascular events.
4. Diabetes mellitus with protein in the urine: In diabetic patients who have microalbuminuria (increased protein in the urine), Diovan may be used to slow the progression of the disease and prevent cardiovascular complications.
5. Prevention of Cardiovascular Complications: In some cases, Diovan may be prescribed to prevent cardiovascular complications in high-risk patients, such as those with risk factors including hypertension, diabetes mellitus, smoke history, and others.

Release form

1. Tablets: This is the most common form of release of Diovan. Tablets may come in different strengths, such as 40 mg, 80 mg, 160 mg or 320 mg.
2. Controlled-release tablets: Some manufacturers may produce Diovan in the form of controlled-release tablets, which allows you to prolong the effect of the drug and reduce the number of doses per day.
3. Combination tablets: Diovan may also be available as combination tablets containing valsartan and other antihypertensive drugs such as hydrochlorothiazide.
4. Powder for suspension: For children or people who have difficulty swallowing hard tablets, Diovan may be available as a powder for suspension.

Pharmacodynamics

1. AT1 receptor blocking: Valsartan binds with high affinity to angiotensin II receptors, specifically blocking them. This results in the prevention of the effects of angiotensin II on these receptors.
2. Reduced peripheral vascular resistance: Blocking AT1 receptors as a result of taking valsartan leads to vasodilation and a decrease in peripheral resistance. This helps reduce vascular resistance and lower blood pressure.
3. Decreased aldosterone production: Valsartan may also decrease the production of aldosterone, a hormone that increases the reabsorption of sodium and water in the kidneys. This helps control blood volume and pressure.
4. Anti-remodeling effects: Angiotensin II receptor antagonists, including valsartan, may have anti-remodeling effects on the heart and blood vessels. This means that they can slow down or prevent negative changes in the structure and function of the heart and blood vessels, such as myocardial hypertrophy and fibrosis.
5. Anti-arrhythmic effect: Valsartan may have a beneficial effect on heart rhythm and prevent some types of arrhythmias.

Pharmacokinetics

1. Absorption: After oral administration of valsartan, it is rapidly and almost completely absorbed from the gastrointestinal tract. Food does not affect its absorption, so the drug can be taken regardless of meals.
2. Maximum concentration (Cmax): The time to reach maximum plasma concentration is usually about 2-4 hours after taking valsartan.
3. Bioavailability: The bioavailability of valsartan when taken orally is about 25-35% due to first pass through the liver.
4. Protein binding: Valsartan binds to plasma proteins, mainly albumin, at a high level (about 94-97%).
5. Metabolism: Valsartan is metabolized in the liver to form an active metabolite (valsartan acid metabolite). The main metabolite is 4-hydroxyvalsartan.
6. Half-life (T½): The half-life of valsartan in the body is about 6 hours, and its active metabolite is about 9 hours.
7. Excretion: Valsartan and its metabolite are excreted mainly through the kidneys in the urine and, to a lesser extent, through the intestines in the bile.
8. Metabolism interactions: Valsartan may interact with other drugs, especially with other antihypertensive drugs, as well as with drugs metabolized via the cytochrome P450 system.

Dosing and administration

Diovan (valsartan) is commonly used to treat hypertension. The standard initial and maintenance dose is 80 mg once daily. Depending on the patient's response to treatment, the dose may be increased to a maximum of 320 mg per day.

In a study involving patients with arterial hypertension living in the Far North, valsartan at a dosage of 160 mg per day was used for 4 weeks. Its effect on circadian changes in blood pressure, lipid, carbohydrate and water-salt metabolism was studied. The antihypertensive activity and tolerability of the drug were also analyzed, showing its effectiveness and good tolerability in this group of patients (Novokrestova et al., 2003).

The drug should be taken with or without food, but it is recommended to take it at the same time every day to maintain a constant level of the drug in the blood. It is important to follow the recommended dosage and not exceed it without consulting your doctor.

Use Diovana during pregnancy

The use of valsartan (Diovan) during pregnancy is not recommended due to the potential risk to the fetus, especially in the second and third trimesters of pregnancy. Valsartan belongs to the group of angiotensin II receptor inhibitors (ARIs), which can cause toxic effects on the fetus.

There is a documented case where the use of valsartan before the 20th week of pregnancy did not lead to abnormalities in the fetus or child after birth. However, this is an exception, and in general such situations require caution and medical supervision (Öztürk, 2012).

As a general rule, ARA II inhibitors, including valsartan, can cause complications such as impaired renal function in the fetus, a decrease in the amount of amniotic fluid, and a slowdown in the development of skull bones. Due to these risks, valsartan is generally not used during pregnancy unless absolutely necessary and there are no other, safer alternatives for treating hypertension.

Contraindications

1. Hypersensitivity: People with a known hypersensitivity to valsartan or any of the components of the drug should avoid its use.
2. Pregnancy: Use of Diovan during pregnancy may be harmful to the fetus, especially in the second and third trimesters, and may lead to the development of birth defects.
3. Cardiogenic shock: Diovan is contraindicated in cardiogenic shock, a condition in which the heart is unable to pump enough blood to maintain normal circulation.
4. Severe renal impairment: The drug should be used with caution in patients with severe renal impairment.
5. Severe hepatic impairment: Diovan should be used with caution in patients with severe hepatic impairment.
6. Hypovolemia and/or hyponatremia: The drug should be used with caution in patients with hypovolemia (decreased blood volume) and/or hyponatremia (low sodium levels in the blood).
7. Children's age: The use of Diovan in children requires special caution and should be carried out under the supervision of a physician.
8. Use with other medications: Before using Diovan in combination with other medications, you should consult your doctor to ensure there are no potential interactions.

Side effects Diovana

1. Headache: One of the most common side effects of Diovan is headache or dizziness. These symptoms are usually temporary and may improve with continued treatment.
2. Hypotension: In some cases, Diovan may cause a decrease in blood pressure, resulting in hypotension (low blood pressure). This may include feeling weak, dizzy, or even losing consciousness.
3. Fatigue and weakness: Some patients may feel tired or weak while taking Diovan.
4. Gastrointestinal disorders: These may include nausea, vomiting, diarrhea, and dyspepsia (indigestion).
5. Hyperkalemia: Diovan may increase blood potassium levels, especially in patients with impaired renal function or taking other medications that may increase potassium levels. This can cause cardiac arrhythmias and other cardiovascular complications.
6. Allergic reactions: Some people may have allergic reactions to Diovan, such as skin rash, itching, swelling of the face or tongue.
7. Increased blood urea and creatinine levels: Diovan may cause increased blood urea and creatinine levels, which is an indicator of impaired renal function.
8. Other rare side effects: Include anemia, thrombocytopenia, elevated liver enzymes, and others.

Overdose

1. Decreased blood pressure: An overdose of valsartan can cause a severe decrease in blood pressure (hypotension), which can lead to dizziness, fainting, and serious complications such as cerebral ischemia or myocardial infarction in some patients.
2. Electrolyte disturbances: Overdose may cause an imbalance of electrolytes in the body, which can lead to hyperkalemia (increased potassium in the blood), especially in patients with impaired renal function.
3. Drowsiness and central nervous system depression: Some patients may experience drowsiness, as well as incoordination, decreased activity, or even coma.
4. Other symptoms: Other symptoms of valsartan overdose may include headache, stomach upset, nausea, vomiting, and increased sensitivity to light.

Interactions with other drugs

1. Other antihypertensive drugs: Concomitant use of Diovan with other antihypertensive drugs, such as diuretics, beta blockers or ACE inhibitors, may lead to an enhanced hypotensive effect and increase the risk of hypotension.
2. Medicines that increase potassium levels: Diovan may increase potassium levels in the blood. Therefore, use of Diovan with other drugs that can also increase potassium levels, such as potassium supplements or potassium-sparing diuretics, may result in hyperkalemia.
3. Drugs that lower potassium levels: Use of Diovan with drugs that can lower blood potassium levels, such as thiazide diuretics or laxatives, may reduce the effectiveness of blood pressure control and increase the risk of hypokalemia.
4. Nephrotoxic drugs: Using Diovan with nephrotoxic drugs, such as some nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, or cancer drugs, may increase the risk of kidney damage.
5. Drugs Metabolized by Cytochrome P450: Valsartan may interfere with the metabolism of other drugs metabolized by the cytochrome P450 system in the liver, which may alter their effectiveness or blood levels.
6. Drugs that increase blood levels of valsartan: Some drugs, such as CYP2C9 inhibitors (eg, fluconazole), may increase blood levels of valsartan, which may result in increased effects and an increased risk of side effects.