No

Calcium Channel Blocker

Treatment of hypertension

C

Clinical effects on the fetus: No data on crossing the placenta

Breast-feeding/lactation: No data on crossing into breast milk. Not recommended due to potential harm to infant.

Hypersensitivity to isradipine or any component; hypotension (<90 mm Hg systolic)

Use cautiously in CHF, hypertrophic cardiomyopathy (IHSS), and in hepatic dysfunction. Safety and efficacy have not been established in pediatric patients. Adjust doses at 2- to 4-week intervals.

>10%: Central nervous system: Headache (dose-related 1.9% to 22%)

1% to 10%:

Cardiovascular: Edema (dose-related 1.2% to 8.7%), palpitations (dose-related 0.8% to 5.1%), flushing (dose-related 0.8% to 5.1%), tachycardia (1% to 3.4%), chest pain (1.7% to 2.7%)

Central nervous system: Dizziness (1.6% to 8%), fatigue (dose-related 0.4% to 8.5%), flushing (9%)

Dermatologic: Rash (1.5% to 2%)

Gastrointestinal: Nausea (1% to 5.1%), abdominal discomfort (0% to 3.3%), vomiting (0% to 1.3%), diarrhea (0% to 3.4%)

Respiratory: Dyspnea (0.5% to 3.4%)

Renal: urinary frequency (1.3% to 3.4%)

0.5% to 1% (Limited to important or life-threatening symptoms): Pruritus, urticaria, cramps of legs and feet, cough, shortness of breath, hypotension, atrial fibrillation, ventricular fibrillation, myocardial infarction, heart failure, abdominal discomfort, constipation, diarrhea, nocturia, drowsiness, insomnia, lethargy, nervousness, weakness, impotence, decreased libido, depression, syncope, paresthesias,transient ischemic attack, stroke, hyperhidrosis, visual disturbance, dry mouth, gingival hyperplasia (incidence unknown), numbness, throat discomfort, leukopenia, elevated liver function tests

The primary cardiac symptoms of calcium blocker overdose include hypotension and bradycardia. The hypotension is caused by peripheral vasodilation, myocardial depression, and bradycardia. Bradycardia results from sinus bradycardia, second- or third-degree atrioventricular block, or sinus arrest with junctional rhythm. Intraventricular conduction is usually not affected so QRS duration is normal (verapamil does prolong the P-R interval and bepridil prolongs the Q-T and may cause ventricular arrhythmias, including torsade de pointes).

In a few reported cases, overdose with calcium channel blockers has been associated with hypotension and bradycardia, initially refractory to atropine but becoming more responsive to this agent when larger doses (approaching 1 g/hour for more than 24 hours) of calcium chloride was administered.

CYP3A3/4 enzyme substrate

Beta-blockers may have increased pharmacokinetic or pharmacodynamic interactions with isradipine.

Calcium may reduce the calcium channel blocker's effects, particularly hypotension.

Rifampin increases the metabolism of the calcium channel blocker; adjust the dose of the calcium channel blocker to maintain efficacy.

Inhibits calcium ion from entering the "slow channels" or select voltage-sensitive areas of vascular smooth muscle and myocardium during depolarization, producing a relaxation of coronary vascular smooth muscle and coronary vasodilation; increases myocardial oxygen delivery in patients with vasospastic angina

Duration: 8-16 hours

Absorption: Oral: 90% to 95%

Protein binding: 95%

Metabolism: In the liver

Bioavailability: Absolute due to first-pass elimination 15% to 24%

Half-life: 8 hours

Time to peak: Serum concentration: 1-1.5 hours

Elimination: Renal excretion by metabolites (cyclic lactone and monoacids)

Adults: 2.5 mg twice daily; antihypertensive response occurs in 2-3 hours; maximal response in 2-4 weeks; increase dose at 2- to 4-week intervals at 2.5-5 mg increments; usual dose range: 5-20 mg/day. Note: Most patients show no improvement with doses >10 mg/day except adverse reaction rate increases

May open capsule; avoid crushing contents

Isradipine alone or in combination with other agents is effective in the management of hypertension.

May cause dizziness or drowsiness

None reported

No information available to require special precautions

Other drugs of this class can cause gingival hyperplasia (ie, nifedipine) but there have been no reports for isradipine

Take as prescribed; do not stop abruptly without consulting prescriber immediately. You may experience headache (if unrelieved, consult prescriber), nausea or vomiting (frequent small meals may help), constipation (increased dietary bulk and fluids may help), or depression (should resolve when drug is discontinued). May cause dizziness or drowsiness; use caution when driving or engaging in tasks that require alertness until response to drug is known. Report unrelieved headache, vomiting, constipation, palpitations, swelling of hands or feet, or sudden weight gain. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to be pregnant. Consult prescriber if breast-feeding.

Do not crush sustained release capsules

Capsule: 2.5 mg, 5 mg

A 1 mg/mL oral liquid was stable for 35 days when refrigerated when compounded as follows:

Shake well before using and keep in refrigerator

MacDonald JL, Johnson CE, and Jacobson P, "Stability of Isradipine in Extemporaneously Compounded Oral Liquids," Am J Hosp Pharm, 1994, 51(19):2409-11.

Westbrook P, Bednarczyk EM, Carlson M, et al, "Regression of Nifedipine-Induced Gingival Hyperplasia Following Switch to a Same Class Calcium Channel Blocker, Isradipine," J Periodontol, 1997, 68(7):645-50.