Valsartan, Background, Effective Action, Uses, Side effects, and 10 Brands in Pakistan

Introduction

Valsartan is an angiotensin-receptor blocker (ARBs) used to treat high blood pressure (hypertension), and heart failure, and to reduce the risk of death after a heart attack. it works by blocking the action of angiotensin II, a chemical that constricts blood vessels and increases blood pressure. By blocking the effects of angiotensin II, Valsartan relaxes blood vessels, reduces blood pressure, and improves blood flow to the heart and other organs.

Background

Hypertension, or high blood pressure, is a major public health concern worldwide, affecting approximately one-third of adults globally. It is a significant risk factor for cardiovascular disease, stroke, and kidney disease, and is estimated to cause over 7 million deaths annually.

The renin-angiotensin-aldosterone system (RAAS) plays a crucial role in the regulation of blood pressure. Angiotensin II, a key component of the RAAS, is a potent vasoconstrictor that increases blood pressure by constricting blood vessels and stimulating the release of aldosterone, a hormone that promotes sodium retention and fluid retention.

Valsartan, an angiotensin-receptor blocker (ARB), was developed to target the RAAS and reduce blood pressure by blocking the action of angiotensin II. Since its approval in 1996, Valsartan has become a widely used medication for the treatment of hypertension, heart failure, and post-myocardial infarction (MI) management.

The development of Valsartan was a significant advancement in the treatment of cardiovascular disease, offering a new and effective option for patients who are intolerant to angiotensin-converting enzyme (ACE) inhibitors or have other comorbidities. This background sets the stage for understanding the actions, uses, and effects of Valsartan, which will be discussed in the following sections.

Mechanism of Action

Valsartan is an angiotensin-receptor blocker (ARB) that works by blocking the action of angiotensin II, a potent vasoconstrictor that increases blood pressure. step-by-step explanation of its mechanism of action are:

Angiotensin II production

The renin-angiotensin-aldosterone system (RAAS) produces angiotensin II in response to low blood pressure, decreased sodium levels, or increased potassium levels.

Angiotensin II binding

Angiotensin II binds to angiotensin receptor type 1 (AT1) in blood vessels, causing vasoconstriction and increased blood pressure.

Valsartan binding

Valsartan binds to AT1 receptors, blocking the action of angiotensin II and reducing vasoconstriction.
By blocking angiotensin II, Valsartan causes blood vessels to relax and dilate, reducing blood pressure.

Decreased aldosterone production

Valsartan also reduces the production of aldosterone, a hormone that promotes sodium retention and fluid retention, further contributing to blood pressure reduction.

Increased renal blood flow

Valsartan increases renal blood flow, which helps to reduce blood pressure and improve kidney function.
By blocking the action of angiotensin II, It reduces blood pressure, improves blood flow, and decreases the workload on the heart, making it an effective treatment for hypertension, heart failure, and post-myocardial infarction management.

Medical Uses of Valsartan

1. Hypertension (High Blood Pressure)

• Purpose: Valsartan is primarily prescribed to manage high blood pressure.
• Mechanism: It works by blocking the effects of angiotensin II, a hormone that causes blood vessels to constrict. By preventing this constriction, it helps to relax and widen blood vessels, which lowers blood pressure.
• Benefits: Effective blood pressure control reduces the risk of complications such as strokes, heart attacks, and kidney damage. it is used alone or in combination with other antihypertensive agents to achieve optimal blood pressure levels.

2. Heart Failure

• Purpose: Valsartan is used in the treatment of heart failure, a condition where the heart cannot pump blood effectively.
• Mechanism: It reduces the strain on the heart by lowering blood pressure and decreasing fluid retention. This is achieved by blocking the action of angiotensin II, which normally causes blood vessels to narrow and promotes fluid retention.
• Benefits: By reducing the workload on the heart and preventing fluid buildup, Valsartan improves symptoms such as shortness of breath and swelling (edema). It also helps to decrease hospitalizations and improve the overall quality of life for heart failure patients.

3. Post-Myocardial Infarction (After a Heart Attack)

• Purpose: Valsartan is used to improve survival and prevent further cardiac events in patients who have suffered a heart attack.
• Mechanism: Following a heart attack, the heart is susceptible to further damage and complications. It helps by reducing blood pressure and preventing the heart from undergoing harmful structural changes (remodelling). This protective effect is particularly valuable for patients who are intolerant to ACE inhibitors.
• Benefits: Valsartan enhances survival rates and reduces the risk of subsequent heart attacks and other cardiovascular issues, thereby contributing to better long-term outcomes in post-heart attack patients.

4. Diabetic Nephropathy (Kidney Protection in Diabetes)

• Purpose: Valsartan is used to protect kidney function in patients with type 2 diabetes and hypertension.
• Mechanism: In diabetic nephropathy, the kidneys are damaged due to high blood pressure and elevated blood sugar levels. It helps to lower blood pressure and reduce proteinuria (excessive protein in the urine), which are key factors in slowing the progression of kidney damage.
• Benefits: By preserving kidney function, Valsartan helps to delay the onset of kidney failure and the need for dialysis or kidney transplantation in diabetic patients with hypertension. This protective effect is crucial for maintaining overall health and quality of life in these patients.

Dosage

The dosage of Valsartan depends on the condition being treated and the patient’s response:

Congestive Heart Failure

• Initial dose: 40 mg orally twice a day
• Maintenance dose: 80 to 160 mg twice a day

Hypertension

• Initial dose: 80 to 160 mg orally once a day
• Maintenance dose: 80 to 320 mg orally once a day

Myocardial Infarction

• Initial dose: 20 mg orally twice a day
• Maintenance dose: 160 mg twice a day

Pediatric Hypertension

• 6 to 16 years:
• Initial dose: 1.3 mg/kg once a day (up to 40 mg)
• Maintenance dose: up to 2.7 mg/kg (up to 160 mg) once a day.

Side Effects of Valsartan

Valsartan is generally well-tolerated, but like all medications, it can cause side effects in some individuals. Some common and potentially serious side effects are the following:

Common Side Effects

• Dizziness or Lightheadedness: Some patients experience dizziness or lightheadedness, especially when standing up quickly. This side effect is more common after the first dose or a dosage increase.
• Fatigue: Feeling tired or fatigued is a common side effect of Valsartan.
• Diarrhea: Some individuals experience diarrhoea . This side effect is usually mild and temporary.

Less Common Side Effects:

• Headache: Headaches may occur in some patients taking Valsartan.
• Nausea or Vomiting: Nausea and vomiting are less common side effects but can occur in some individuals.
• Muscle Pain or Weakness: Valsartan causes muscle pain or weakness in some patients. This could be a sign of a more serious condition known as rhabdomyolysis, although this is rare.
• Upper Respiratory Infections: Some patients experience upper respiratory tract infections, such as the common cold while taking Valsartan.

Serious Side Effects

• Kidney Problems: Valsartan can cause changes in kidney function, particularly in patients with pre-existing kidney disease or those taking other medications that affect the kidneys. Signs of kidney problems include changes in urine output, swelling in the ankles or feet, and difficulty breathing.
• High Potassium Levels (Hyperkalemia): It increases potassium levels in the blood, leading to symptoms such as muscle weakness, irregular heartbeat, and numbness or tingling in the hands, feet, or lips.
  Liver Problems: Rarely, it causes liver problems, which can manifest as yellowing of the skin or eyes (jaundice), dark urine, abdominal pain, or unusual fatigue.
• Allergic Reactions: Some individuals experience allergic reactions to Valsartan, which can include rash, itching, swelling of the face, lips, or tongue, severe dizziness, or difficulty breathing.

Interactions with other medications

Valsartan may interact with other medications, including:

1. Potassium-sparing diuretics: Taking potassium-sparing diuretics (e.g., spironolactone, triamterene) with valsartan can increase potassium levels in the blood.
2. Potassium supplements: Taking potassium supplements with valsartan can increase potassium levels in the blood.
3. ACE inhibitors: Taking ACE inhibitors (e.g., lisinopril, enalapril) can increase the risk of kidney problems and high potassium levels.
4. Angiotensin receptor-neprilysin inhibitors (ARNIs): Taking ARNIs (e.g.,  increase the risk of kidney problems and high potassium levels.
5. Nonsteroidal anti-inflammatory drugs (NSAIDs): Taking NSAIDs (e.g., ibuprofen, naproxen) with it can increase the risk of kidney problems.
6. Lithium: Taking lithium with it can increase lithium levels in the blood.
7. Furosemide: Taking furosemide with valsartan can increase the risk of kidney problems.
8. Rifampin: Taking rifampin with valsartan can decrease the effectiveness of valsartan.
9. Antacids: Taking antacids with it decreases the absorption of valsartan.
10. Corticosteroids: Taking corticosteroids with them can increase the risk of kidney problems.

Brand names in Pakistan

The following brands of Valsartan available in Pakistan are:

1. Angiotan: manufactured by Efroze Chemical Industries (PVT) LTD
2. Diovan: manufactured by Novartis Pharma (PAK) LTD
3. Extor: contains the active ingredients Valsartan and Amlodipine.
4. Valsar: manufactured by Dawaai.
5. Dival: manufactured by Ethical Laboratories (PVT) LTD
6. Diotan 3H: manufactured by Hamaz Pharmaceutical (PVT) LTD
7. Listan: manufactured by Lexicon Pharmaceuticals (PVT) LTD
8. Nuval: manufactured by Pharmevo (PVT) LTD
9. Sofvasc-V: manufactured by Wilsons Pharmaceuticals
10. Valken: manufactured by Kanel Pharmaceuticals
11. Valstar: manufactured by Consolidated Chemical Laboratories (PVT) LTD
12. Valtan: manufactured by English Pharmaceuticals Industries
13. Valtec: manufactured by Tabros Pharma
14. Valtn: manufactured by Kurative Pak (PVT) LTD
15. Varlan: manufactured by Siza International (PVT) LTD
16. Vatin: manufactured by Everest Pharmaceuticals.