Olmesartan

What Does Olmesartan Do?

Olmesartan is a medication used predominantly to treat adults and children (over age 6) with high blood pressure, as well as chronic heart failure. It may be employed to manage diabetic kidney disease. 

How Does Olmesartan Work? (the complicated stuff)

Olmesartan works by preventing angiotensin II, a potent vasoconstrictor, from binding to its receptor. This action inhibits the narrowing of blood vessels and the release of aldosterone, a hormone causing sodium and water retention in the body. Consequently, Olmesartan relaxes blood vessels, lowers blood pressure, and reduces the workload on the heart. 

Drug Type and Category of Olmesartan

Olmesartan belongs to the category of angiotensin II receptor blockers (ARBs).

What dosage of Olmesartan should you be taking?

NHS Guidelines ¹

Adults:

• Starting Dose: Begin with 10 mg taken once daily.
• Adjustment: If blood pressure remains uncontrolled after two weeks, the dose may be increased to 20 mg or 40 mg once daily.
• Maximum Dose: The maximum recommended dose is 40 mg once daily.

Children (6 to 16 years old):

• Weight-Based Dosing:
• For children weighing 20 to less than 35 kg: 10 mg once daily.
• For children weighing 35 kg or more: 20 mg once daily.
• Adjustment: If blood pressure is not adequately controlled after two weeks, the dose may be increased:
• For children weighing less than 35 kg: increase to 20 mg once daily.
• For children weighing 35 kg or more: increase to 40 mg once daily.
• Maximum Dose: For children weighing less than 35 kg, the daily dose should not exceed 20 mg. For those weighing 35 kg or more, the daily dose should not exceed 40 mg.

Special Considerations:

• Renal Impairment: In patients with mild to moderate renal impairment (creatinine clearance of 20–60 mL/min), the maximum dose is 20 mg once daily. The use of olmesartan in patients with severe renal impairment (creatinine clearance <20>
• Hepatic Impairment: No adjustment of dosage is required for patients with mild hepatic impairment. In patients with moderate hepatic impairment, an initial dose of 10 mg once daily is recommended, and the maximum dose should not exceed 20 mg once daily. There is no experience of olmesartan in patients with severe hepatic impairment; therefore, use is not recommended in this patient group.

Administration:

• Olmesartan can be taken with or without food.
• It is recommended to take the medication at the same time each day to help remember.
• The tablet should be swallowed whole with a sufficient amount of fluid (e.g., one glass of water). The tablet should not be chewed. 

What are the side-effects of Olmesartan?

Common Side Effects:

1. Dizziness or Lightheadedness: Especially when standing up quickly, due to the blood pressure-lowering effects.
2. Headache: Some individuals may experience headaches, which is a common side effect of antihypertensive medications.
3. Back Pain: A general body discomfort, particularly in the lower back.
4. Fatigue: Some people may feel unusually tired or lethargic.

Serious Side Effects (Less Common):

1. Hyperkalemia (High Potassium Levels): Olmesartan can increase potassium levels in the blood, which can be dangerous if levels become too high. Symptoms may include muscle weakness, fatigue, and irregular heart rhythms.
2. Angioedema: A rare but serious condition involving swelling of the face, lips, tongue, throat, or extremities, which can lead to difficulty breathing.
3. Low Blood Pressure (Hypotension): In some cases, olmesartan can cause blood pressure to drop too much, especially when starting the medication or increasing the dose. This may result in dizziness, fainting, or confusion.
4. Liver Problems: Though rare, some individuals may experience liver enzyme changes or jaundice (yellowing of the skin or eyes).
5. Kidney Dysfunction: Olmesartan can impact kidney function, especially in people with pre-existing kidney disease. Monitoring of kidney function is recommended during treatment.
6. Rash: Some people may develop a rash, indicating an allergic reaction.
7. Gastrointestinal Issues: Diarrhea is a possible side effect, especially in long-term use, and has been associated with a condition known as sprue-like enteropathy, which involves severe, chronic diarrhea and weight loss.

Rare and Severe Reactions:

• Elevated Blood Urea Nitrogen (BUN) and Creatinine: This may indicate impaired kidney function.
• Myocardial Infarction (Heart Attack): In rare cases, sudden changes in blood pressure may lead to cardiovascular problems, particularly in those with pre-existing heart conditions.

Tips for Managing Side Effects:

• If dizziness or lightheadedness occurs, it's important to rise slowly from a sitting or lying position.
• Report any swelling, difficulty breathing, or chest pain to a healthcare provider immediately.
• Regular blood tests to monitor kidney function, liver enzymes, and potassium levels are essential during treatment.

Interactions

1. Other Blood Pressure Medications:

• Diuretics (Water Pills): Combining olmesartan with diuretics (e.g., hydrochlorothiazide) can cause an increased risk of low blood pressure (hypotension), especially when starting treatment. Diuretics can also increase potassium levels, which may interact with olmesartan's potential to raise potassium, leading to hyperkalemia (high potassium).
• ACE Inhibitors (Angiotensin-Converting Enzyme Inhibitors): Drugs like enalapril or lisinopril, when used with olmesartan, can increase the risk of hyperkalemia and kidney problems. These medications are often used in combination for heart failure but should be carefully monitored.
• Calcium Channel Blockers: Medications like amlodipine, which help relax and widen blood vessels, can enhance the blood pressure-lowering effects of olmesartan, sometimes causing blood pressure to drop too much.

2. Medications That Affect Potassium Levels:

• Potassium Supplements: Taking potassium supplements alongside olmesartan may increase the risk of hyperkalemia, leading to dangerous consequences like irregular heartbeats. Avoid potassium-rich foods or supplements unless instructed by a healthcare provider.
• Potassium-Sparing Diuretics: Drugs like spironolactone, triamterene, or amiloride are potassium-sparing and can increase potassium levels when combined with olmesartan, leading to hyperkalemia.

3. Nonsteroidal Anti-Inflammatory Drugs (NSAIDs):

• Ibuprofen, Naproxen, and Other NSAIDs: These medications can reduce the blood pressure-lowering effects of olmesartan and may increase the risk of kidney problems, particularly with long-term use. If combined, kidney function should be monitored closely.

4. Lithium:

• Olmesartan can increase the blood levels of lithium, a drug used to treat bipolar disorder. High lithium levels can lead to lithium toxicity, which can cause symptoms like nausea, tremors, and confusion.

5. Rifampin:

• Rifampin, an antibiotic often used to treat tuberculosis, can reduce the effectiveness of olmesartan by increasing its metabolism. This may decrease olmesartan's blood pressure-lowering effect.

6. Other Drugs That Can Affect Blood Pressure:

• Alpha-blockers (e.g., doxazosin) and beta-blockers (e.g., atenolol) can also lower blood pressure, and their combination with olmesartan may cause an exaggerated blood pressure-lowering effect.
• Sympathomimetic Medications (e.g., decongestants like pseudoephedrine): These can counteract the blood pressure-lowering effect of olmesartan.

7. Alcohol:

• Drinking alcohol while taking olmesartan can enhance the blood pressure-lowering effect, leading to an increased risk of dizziness, lightheadedness, or fainting.

8. Herbal Supplements:

• Certain herbal supplements, such as licorice or ginseng, can affect blood pressure or potassium levels and may interact with olmesartan.

Monitoring and Consultation:

• Kidney Function: Olmesartan can affect kidney function, especially when combined with other medications that impact the kidneys (such as NSAIDs or ACE inhibitors). Regular kidney function tests are important.
• Potassium Levels: Since olmesartan can raise potassium levels, interactions with other drugs that also increase potassium (e.g., potassium supplements, potassium-sparing diuretics) should be closely monitored.
• Always inform your healthcare provider of any other medications, including over-the-counter drugs, supplements, and herbal remedies, before starting olmesartan.

Natural Alternatives to Olmesartan

1. Garlic (Allium sativum):

• How it Works: Garlic is believed to help lower blood pressure by increasing the production of nitric oxide, which relaxes blood vessels and improves circulation.
• Studies: Some studies have shown that garlic supplements can reduce both systolic and diastolic blood pressure in people with hypertension ?2;.
• How to Use: Fresh garlic, garlic supplements, or aged garlic extract can be consumed. A typical dose is 600-1,200 mg of garlic extract per day ?2;.

2. Hibiscus Tea:

• How it Works: Hibiscus contains antioxidants that may help relax blood vessels and lower blood pressure.
• Studies: Several studies have found that hibiscus tea can help lower both systolic and diastolic blood pressure, particularly in people with mild to moderate hypertension ?3;.
• How to Use: Drinking 2-3 cups of hibiscus tea daily has been shown to be effective ?3;.

3. Omega-3 Fatty Acids (Fish Oil):

• How it Works: Omega-3 fatty acids, found in fatty fish (e.g., salmon, mackerel, sardines) and fish oil supplements, can reduce blood pressure by decreasing inflammation and improving blood vessel function.
• Studies: Research has shown that omega-3 supplementation can significantly lower blood pressure, particularly in people with high blood pressure ?.
• How to Use: Aim for 1,000-2,000 mg of EPA and DHA (the active omega-3 compounds) per day, either from fish or supplements ?.

4. Coenzyme Q10 (CoQ10):

• How it Works: CoQ10 is an antioxidant that helps improve blood vessel function and energy production in cells.
• Studies: Some studies suggest that CoQ10 supplementation can reduce systolic and diastolic blood pressure by improving the function of blood vessels ?.
• How to Use: The recommended dose is 100-200 mg per day ?.

5. Magnesium:

• How it Works: Magnesium helps regulate blood pressure by relaxing blood vessels and improving blood flow.
• Studies: Several studies have shown that magnesium supplementation can lower both systolic and diastolic blood pressure, especially in people who are magnesium deficient ?.
• How to Use: The recommended daily intake of magnesium is around 300-400 mg, which can be obtained through food (e.g., leafy greens, nuts, seeds) or supplements ?.

6. Potassium:

• How it Works: Potassium helps balance the negative effects of sodium on blood pressure and is essential for proper heart and muscle function.
• Studies: Increasing potassium intake can help lower blood pressure, especially in people with hypertension ?.
• How to Use: Aim for 3,500-4,700 mg of potassium daily through foods like bananas, potatoes, tomatoes, spinach, and oranges ?.

7. Beetroot Juice:

• How it Works: Beetroot is high in nitrates, which the body converts into nitric oxide, helping to relax and dilate blood vessels.
• Studies: Research has shown that beetroot juice can significantly lower blood pressure, especially in people with high blood pressure ?.
• How to Use: Drinking 250-500 ml of beetroot juice daily has been shown to have a blood pressure-lowering effect ?.

8. Yoga and Meditation:

• How it Works: Stress reduction techniques like yoga, meditation, and deep breathing exercises can help lower blood pressure by reducing stress hormones and promoting relaxation.
• Studies: Research has demonstrated that regular practice of yoga and mindfulness meditation can reduce both systolic and diastolic blood pressure ?.
• How to Use: Aim for 20-30 minutes of yoga or meditation daily to manage stress and lower blood pressure ?.

9. Exercise:

• How it Works: Regular physical activity helps strengthen the heart, improve circulation, and reduce blood pressure.
• Studies: Consistent aerobic exercise, such as walking, cycling, or swimming, has been shown to lower blood pressure over time ?1;?.
• How to Use: Aim for at least 150 minutes of moderate-intensity exercise per week (e.g., 30 minutes a day, five days a week) ?1;?.

10. Cinnamon:

• How it Works: Cinnamon contains compounds that may help dilate blood vessels and improve blood flow.
• Studies: Some studies suggest that cinnamon can lower blood pressure, particularly in people with type 2 diabetes ?1;?1;.
• How to Use: Adding cinnamon to food or drinks (e.g., tea, oatmeal) may provide benefits. A typical dose is 1/2 to 1 teaspoon of ground cinnamon per day ?1;?1;.

Interesting facts about Olmesartan

Olmesartan can be particularly helpful for people with diabetic nephropathy (kidney disease caused by diabetes) or chronic kidney disease (CKD). It helps protect the kidneys from further damage by reducing protein in the urine, which is a marker of kidney dysfunction.

Olmesartan has a long half-life (about 13 hours), which means it stays in the body for a longer time and can be taken once a day. This is convenient for patients as they do not need to take multiple doses throughout the day.

While Olmesartan is not recommended during pregnancy, particularly in the second and third trimesters (due to potential harm to the fetus), some studies have shown that it can be used in the first trimester with close medical supervision.

Disclaimer

This article is generated for informational purposes only. It was created in January 2025. Medications and medical guidance can change over time. Therefore, it is essential to consult with your general practitioner or healthcare provider before making any decisions regarding medications or treatment plans. Your GP can provide personalised advice based on your specific health needs and conditions.

References

1. https://www.nhs.uk/medicines/olmesartan/how-and-when-to-take-olmesartan/
2. Ried, K., et al. (2013). Garlic and Blood Pressure: A Systematic Review and Meta-Analysis. Journal of Clinical Hypertension.
3. McKay, D. L., & Blumberg, J. B. (2007). Hibiscus sabdariffa L. in the Management of Hypertension and Hyperlipidemia: A Review. Phytotherapy Research.
4. Grosso, G., et al. (2014). Omega-3 Fatty Acids and Cardiovascular Disease: A Review. European Journal of Clinical Nutrition.
5. Rosenfeldt, F. L., et al. (2007). Coenzyme Q10 in the Treatment of Hypertension. Journal of Hypertension.
6. Rosanoff, A., Weaver, C. M., & Raghavan, R. (2012). The Importance of Magnesium in Clinical Healthcare. Nutrients.
7. Whelton, P. K., et al. (2018). Potassium Intake and Risk of Stroke and Cardiovascular Disease: A Meta-analysis. Journal of Clinical Hypertension.
8. Dominguez, L. J., et al. (2015). Beetroot Juice and Blood Pressure: A Review of Its Efficacy in Cardiovascular Health. International Journal of Cardiology.
9. Cramer, H., et al. (2014). Yoga for Hypertension: A Systematic Review and Meta-analysis. Journal of Human Hypertension.
10. Cornelissen, V. A., & Fagard, R. H. (2005). Effects of Endurance Training on Blood Pressure, Blood Lipids, and Body Weight: A Meta-analysis. Journal of Hypertension.
11. Al-Zoreky, N. S. (2009). Cinnamon and Its Medicinal Properties: A Review. Journal of Medicinal Food.