Pharmacology

Olmesartan medoxomil is a prodrug that is hydrolyzed to the active form, olmesartan, during absorption in the gastrointestinal tract. It is an angiotensin II receptor blocker (ARB), specifically acting on the AT₁ receptor subtype. By blocking the vasoconstrictor and aldosterone-secreting effects of angiotensin II, it reduces blood pressure, peripheral resistance, and afterload, improving cardiovascular outcomes.

Dosage & Administration

Adults:

  • Hypertension: Initial dose: 20 mg once daily.

    • If further blood pressure reduction is needed, dose may be increased to 40 mg once daily.

    • Can be used alone or in combination with other antihypertensive agents.

Children (6–16 years):

  • 10–20 kg: 10 mg once daily.

  • 20 kg: 20 mg once daily.

Note: Not recommended for children under 6 years due to limited data.

Drug Interactions

  • NSAIDs: May reduce antihypertensive effect; risk of renal impairment.

  • Potassium-sparing diuretics or potassium supplements: Risk of hyperkalemia.

  • Lithium: Increased serum lithium levels and toxicity.

  • Other antihypertensives: Additive hypotensive effect.

  • Aliskiren: Increased risk of renal dysfunction, hyperkalemia, and hypotension when combined in diabetics.

Contraindications

  • Hypersensitivity to olmesartan or any of its components.

  • Pregnancy (especially 2nd and 3rd trimesters).

  • Severe renal impairment (CrCl <30 mL/min).

  • Biliary obstruction.

Side Effects

  • Common: Dizziness, headache, back pain, bronchitis, hyperglycemia.

  • Less common: Hypotension, syncope, angioedema, increased creatinine, hyperkalemia, diarrhea (notably associated with sprue-like enteropathy).

  • Rare: Rhabdomyolysis, liver enzyme elevation.

Pregnancy & Lactation

  • Pregnancy: Category D – Can cause injury and even death to the developing fetus when used during the second and third trimesters.

  • Lactation: Not recommended due to potential for adverse effects on the nursing infant. Use alternative if breastfeeding is necessary.

Precautions & Warnings

  • Monitor blood pressure, renal function, and electrolytes regularly.

  • Use with caution in patients with renal artery stenosis or pre-existing renal impairment.

  • Caution in volume- or salt-depleted patients (e.g., those on diuretics).

  • Discontinue immediately if pregnancy is detected.

  • Risk of sprue-like enteropathy (chronic diarrhea with weight loss).

Overdose Effects

  • Symptoms: Hypotension, tachycardia; bradycardia may occur due to vagal stimulation.

  • Treatment: Supportive care; consider gastric lavage if recent ingestion. Hemodialysis is not effective due to high protein binding.

Therapeutic Class

  • Angiotensin II Receptor Blockers (ARBs)

Storage Conditions

  • Store at 25°C (77°F); excursions permitted to 15–30°C (59–86°F).

  • Protect from moisture and light.

  • Keep out of reach of children.

Chemical Structure

  • IUPAC Name: (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl 4-(1-hydroxy-1-methylethyl)-2-propyl-1-[[2′-(1H-tetrazol-5-yl)[1,1′-biphenyl]-4-yl]methyl]-1H-imidazole-5-carboxylate

  • Molecular Formula: C₃₀H₃₀N₆O₆

  • Molecular Weight: 558.59 g/mol

 

  
  
Scroll to Top