Amlodipine

What it is used for

• Adjunctive therapy for refractory heart failure (advanced mitral valve degeneration as an afterload reducer)
• Arterial vasodilator for refractory CHF secondary to mitral regurgitation
• Systemic hypertension in dogs with chronic renal disease
• Systemic hypertension (2nd step drug)
• Systemic hypertension
• Systemic hypertension (1st step drug)
• Systemic hypertension
• Systemic hypertension

How it is given

Possible side effects

• Cats: Infrequent azotemia, lethargy, hypokalemia, reflex tachycardia, weight loss
• Dogs: Gingival hyperplasia (with long-term use)
• Anorexia and hypotension (early in therapy)

Cautions & contraindications

• Patients with cardiogenic shock
• Advanced aortic stenosis (relative contraindication)
• Use with caution in patients with heart failure (due to slight negative inotropic effects)
• Use with caution in patients with hepatic dysfunction
• > **Renal Considerations in Cats**: There is concern that using amlodipine alone for treating hypertension in cats with renal disease may expose glomeruli to higher pressures secondary to efferent arteriolar constriction (caused by localized RAAS activation). Using an ACE inhibitor concurrently may help prevent this, though routine use of ACE inhibitors with amlodipine in cats with CKD remains somewhat controversial. - **Cardiac Disease**: Use cautiously in patients with heart failure due to slight negative inotropic effects. - **Hepatic Disease**: Use cautiously as the drug is extensively metabolized in the liver; half-life may be prolonged. - **Pregnancy**: Fetotoxic in laboratory animals at very high doses; prolonged labor in rats. FDA Category C.

Drug interactions

• Diuretics: Concomitant use may cause additive hypotension.
• Beta-blockers: Concomitant use may cause additive hypotension.
• Vasodilators: Concomitant use may cause additive hypotension.
• Fentanyl: May cause hypotension if used concurrently.
• Grapefruit juice/powder: May alter bioavailability of amlodipine.
• Cimetidine: May impair hepatic metabolism of amlodipine, increasing circulating levels
• Cyclosporine: May impair hepatic metabolism of amlodipine, increasing circulating levels
• Ketoconazole: May impair hepatic metabolism of amlodipine, increasing circulating levels
• Itraconazole: May impair hepatic metabolism of amlodipine, increasing circulating levels
• Rifampin: CYP3A4 inducer; may reduce circulating amlodipine levels
• ACE inhibitors: Increased risk of hypotension when combined

Frequently asked questions