Olmesartan

BRAND NAMES 

Azor: Azor includes a dosage of 5 mg amlodipine and 20 mg olmesartan. Amlodipine works by relaxing the muscles of the heart and blood vessels, while olmesartan reduces blood pressure and improves blood flow. Azor is used to treat low blood pressure, which may reduce the risk of a stroke or heart attack.

Benicar: It contains Olmesartan an angiotensin II receptor antagonist used to treat and manage hypertension. Benicar tablets are available in three strengths: 5 mg, 20 mg, and 40 mg.

Benicar HCT: Benicar HCT is a combination of hydrochlorothiazide and olmesartan used to treat high blood pressure. It is available in strengths of 12.5 mg/20 mg, 12.5 mg/40 mg, and 25 mg/40 mg.

Tribensor: It includes compounds of amlodipine, hydrochlorothiazide, and olmesartan. It is available in the following strengths: 5 mg/12.5 mg/20 mg, 5 mg/12.5 mg/40 mg, 5 mg/25 mg/40 mg, and 10 mg/12.5 mg/40 mg.

MECHANISM OF ACTION

Olmesartan works as an angiotensin II receptor antagonist, disrupting the renin-angiotensin-aldosterone pathway. Olmesartan is an antagonist that binds to both angiotensin type I (AT-I) and AT-II receptors. Olmesartan is both reversible and selective, binding to the AT-I receptor with more than 12,000 times its binding capacity for AT-II variants. This chemical blocks these receptors in the adrenal gland and vascular smooth muscle locations, particularly the arterioles. Physiologically, angiotensin II binds to the AT-I and AT-II receptors, causing the adrenal gland to produce aldosterone and arterial vasoconstriction.

Olmesartan's competitive binding antagonizes these actions, lowering blood pressure by reducing arteriolar resistance via vasodilation. Olmesartan inhibits aldosterone release from the adrenal cortex's zona glomerulosa by competitively blocking AT-II binding to its receptor. Reduced serum aldosterone levels result in decreased expression of ENaC channels inside the nephron's distal collecting tubule, resulting in lower salt reabsorption. Natriuresis and osmotic diuresis occur from decreased expression of the ENaC channel.

PHARMACOKINETICS

Absorption:

• An oral tablet undergoes gastrointestinal absorption.
• The bioavailability is around 26% and does not vary with meal consumption.

Distribution:

Its distribution volume is approximately 17 L due to its strong affinity for plasma proteins.

Metabolism:

During gastrointestinal absorption, ester hydrolysis converts olmesartan medoxomil to olmesartan quickly and completely. The absence of detectable quantities of olmesartan medoxomil in plasma or excreta indicated the quick first-pass metabolism.

Elimination:

• Olmesartan is eliminated mostly through the feces in their unaltered form. Approximately 10–16% of the systemically accessible dosage is lost in the urine.
• The average plasma half-life of olmesartan is reported to be between 10 and 15 hours following repeated oral dosing.

PHARMACODYNAMICS:

Individuals with an active renin-angiotensin-aldosterone system, such as volume- or salt-depleted individuals (e.g., those taking large doses of diuretics), may have symptomatic hypotension after beginning olmesartan therapy. Begin therapy while being closely monitored by your physician. If hypotension occurs, keep the patient supine and, if necessary, deliver an intravenous infusion of normal saline. A transient hypotensive reaction is not a reason to discontinue treatment, which may generally be continued without trouble once blood pressure has returned to normal.

CONTRAINDICATIONS

Do not provide aliskiren with olmesartan medoxomil tablets in individuals with diabetes.

DRUG INTERACTIONS

• Colesevelam (Welchol) is a medication used to treat type 2 diabetes-related elevated blood sugar and cholesterol.
• An ACE inhibitor is a medication used to treat high blood pressure, heart failure, and some renal diseases.
• Lithium is a medication for some mental health disorders.
• A diuretic, commonly known as a water pill, is intended to decrease edema (fluid retention) and blood pressure.
• Aliskiren (Tekturna) is a medication for high blood pressure.
• A non-steroidal anti-inflammatory drug (NSAID), such as ibuprofen, naproxen, and others, are included in many prescription and OTC medicines for pain, swelling, and fever.

SIDE EFFECTS

The most common side effects of olmesartan include

• Diarrhea
• Headache
• Backache
• High blood sugar
• High triglycerides
• Bronchitis
• Fever and body pains
• Sinus infection
• Sure throat
• Blood in urine

Severe side effects of olmesartan include

• Low blood pressure. Symptoms include:
  • Dizziness
  • Faintness
• Liver problems. Symptoms include:
  • Itchy skin
  • Yellowing of skin and eyes
  • Ache in the upper right portion of the stomach
• Allergic reaction. Symptoms include:
  • Swelling of tongue, throat, lips, and face
• Kidney problems

TOXICITY:

Toxic effects may also include impaired eyesight, angina, vertigo, lightheadedness, and diaphoresis. These probable toxicities closely resemble the medication's side effect profile. There is no antidote for olmesartan, but activated charcoal may be appropriate if consumed within four hours of decontamination. Supportive procedures include monitoring vital signs every six hours after ingestion for evidence of hypotension or hemodynamic instability. To increase venous return to the heart, the patient should raise the legs while supine. If severe hypotension persists, vasopressors may be used in extreme cases.