Nurses Compass
Drug Guide
Olmesartan Medoxomil
Classification
Therapeutic: Antihypertensive
Pharmacological: Angiotensin II Receptor Blocker (ARB)
FDA Approved Indications
- Treatment of hypertension to lower blood pressure and reduce the risk of cardiovascular events
Mechanism of Action
Olmesartan selectively blocks the binding of angiotensin II to the AT1 receptor, resulting in vasodilation and reduced aldosterone secretion, thereby lowering blood pressure.
Dosage and Administration
Adult: Typically, 20 mg once daily, may be adjusted up to 40 mg or down based on response.
Pediatric: Not generally recommended for pediatric use.
Geriatric: Start at lower doses. Monitor for hypotension.
Renal Impairment: Adjust dose cautiously. Use in severe impairment with caution.
Hepatic Impairment: No specific adjustment required, but monitor closely.
Pharmacokinetics
Absorption: Well absorbed orally, food can reduce peak plasma concentration but does not affect overall absorption.
Distribution: Extensively bound to plasma proteins (~99%).
Metabolism: Metabolized to active metabolites; undergoes hydrolysis in the gut and liver.
Excretion: Excreted primarily via feces and urine.
Half Life: Approximately 13 hours.
Contraindications
- Hypersensitivity to olmesartan or other ARBs.
- Pregnancy, especially in second and third trimesters.
Precautions
- Use cautiously in volume-depleted or salt-depleted patients. Monitor renal function and electrolytes regularly.
Adverse Reactions - Common
- Dizziness (Common)
- Headache (Common)
- Diarrhea (Uncommon)
Adverse Reactions - Serious
- Angioedema (Rare)
- Hyperkalemia (Uncommon)
- Hypotension (Uncommon)
Drug-Drug Interactions
- Other antihypertensives, diuretics, potassium-sparing diuretics, NSAIDs (may reduce efficacy or increase risk of renal impairment).
Drug-Food Interactions
- No significant food interactions, though similar to other ARBs, avoid excessive potassium intake.
Drug-Herb Interactions
- Caution with herbal supplements that can influence blood pressure or potassium levels (e.g., garlic, St. John’s Wort).
Nursing Implications
Assessment: Monitor blood pressure, renal function, and serum electrolytes periodically.
Diagnoses:
- Risk for decreased cardiac output related to blood pressure changes.
- Risk for electrolyte imbalance.
Implementation: Administer as prescribed, typically once daily. Educate patient about potential side effects and importance of regular monitoring.
Evaluation: Assess for blood pressure control, adverse reactions, and patient adherence.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Notify healthcare provider if signs of angioedema (swelling of face, lips, tongue, or throat) occur.
- Be aware of symptoms of hyperkalemia (muscle weakness, irregular heartbeat).
- Avoid potassium-containing salt substitutes unless directed.
- Report any significant changes in blood pressure.
Special Considerations
Black Box Warnings:
- Pregnancy risk; can cause fetal injury and death; discontinue as soon as pregnancy is detected.
Genetic Factors: No specific genetic considerations currently emphasized.
Lab Test Interference: May interfere with certain lab tests involving blood potassium levels.
Overdose Management
Signs/Symptoms: Hypotension, dizziness, tachycardia or bradycardia, electrolyte disturbances.
Treatment: Supportive care, discontinue medication, monitor vital signs and electrolytes, provide fluids for hypotension.
Storage and Handling
Storage: Store at room temperature (68°F to 77°F/20°C to 25°C), away from moisture and light.
Stability: Stable under recommended storage conditions.