Nurses Compass
Drug Guide
Amlodipine Besylate and Telmisartan
Classification
Therapeutic: Antihypertensive, combination agent
Pharmacological: Calcium channel blocker (Amlodipine), Angiotensin II receptor blocker (Telmisartan)
FDA Approved Indications
- Hypertension
Mechanism of Action
Amlodipine inhibits calcium ion influx into vascular smooth muscle and cardiac muscle, leading to vasodilation; Telmisartan selectively blocks angiotensin II receptor subtype 1 (AT1), reducing vasoconstriction and aldosterone secretion, thereby lowering blood pressure.
Dosage and Administration
Adult: Typically, 2.5-10 mg once daily, titrated according to response; maximum dose usually 10 mg/day.
Pediatric: Not approved for use in pediatric patients.
Geriatric: Start at lower dose, titrate cautiously due to increased sensitivity and comorbidities.
Renal Impairment: Adjust dose with caution, monitor blood pressure and renal function.
Hepatic Impairment: Use with caution; no specific dose adjustment established.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Amlodipine and telmisartan are extensively protein-bound.
Metabolism: Amlodipine undergoes hepatic metabolism (primarily via CYP3A4); telmisartan undergoes minimal hepatic metabolism.
Excretion: Amlodipine excreted via urine and feces; telmisartan is mainly excreted unchanged in feces.
Half Life: Amlodipine approximately 30-50 hours; telmisartan approximately 24 hours.
Contraindications
- Hypersensitivity to amlodipine or telmisartan.
- Pregnancy (especially second and third trimesters) due to risk of fetal toxicity.
Precautions
- Monitor for angioedema, hypotension, and renal function deterioration. Use with caution in patients with hepatic impairment, volume-depleted patients, or those taking other antihypertensives.
Adverse Reactions - Common
- Swelling (edema) (Common)
- Dizziness, fatigue (Common)
- Headache (Common)
Adverse Reactions - Serious
- Angioedema (Rare)
- Hypotension (Rare)
- Elevated serum potassium or renal dysfunction (Rare)
Drug-Drug Interactions
- Other antihypertensives, diuretics, potassium supplements, NSAIDs (may reduce effectiveness of telmisartan).
Drug-Food Interactions
- Avoid excessive potassium intake.
- Alcohol can intensify blood pressure lowering effects.
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor blood pressure, renal function, serum potassium.
Diagnoses:
- Ineffective tissue perfusion (renal or cerebral) related to hypotension or vasodilation.
- Risk for electrolyte imbalance.
Implementation: Administer as prescribed, monitor response, assess for adverse effects.
Evaluation: Aim for controlled blood pressure without adverse effects.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Do not discontinue abruptly.
- Monitor blood pressure regularly.
- Report signs of swelling, dizziness, or hyperkalemia.
Special Considerations
Black Box Warnings:
- Pregnancy: risk of fetal injury; discontinue as soon as pregnancy is detected.
Genetic Factors: Genetic variations in CYP3A4 may affect amlodipine metabolism.
Lab Test Interference: None noted.
Overdose Management
Signs/Symptoms: Severe hypotension, tachycardia, bradycardia, dizziness, somnolence.
Treatment: Supportive care, IV fluids, vasopressors as needed, monitor ECG and vital signs.
Storage and Handling
Storage: Store at room temperature, 20-25°C; protect from moisture and light.
Stability: Stable through expiration when stored properly.