isradipine

Absorption: Well absorbed following oral administration but extensively metabolized, resulting in ↓ bioavailability.

Distribution: Unknown.

Protein Binding: 95%.

Metabolism/Excretion: Completely metabolized by the liver.

Half-Life: 8 hr.

Time/Action Profile ⬆ ⬇

(antihypertensive effects‡)

ROUTE	ONSET	PEAK	DURATION
PO	<2 hr	2–3 hr	12 hr

‡For single doses, maximal antihypertensive effect during chronic dosing may take 2–4 wk.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Sick sinus syndrome;
2nd- or 3rd-degree AV block (unless an artificial pacemaker is in place);
Systolic BP <90 mm Hg;
Lactation: Lactation.

Use Cautiously in:

Severe hepatic impairment (dose ↓ recommended);
Severe renal impairment;
History of serious ventricular arrhythmias or HF;
OB: Safety not established in pregnancy;
Geri: Dose recommended for most agents; risk of hypotension.

Adv. Reactions/Side Effects ⬆ ⬇

CV: peripheral edema, HF, ARRHYTHMIAS, bradycardia, chest pain, hypotension, palpitations, syncope, tachycardia

Derm: dermatitis, erythema multiforme, flushing, photosensitivity, pruritus/urticaria, rash, STEVENS-JOHNSON SYNDROME, sweating

EENT: blurred vision, disturbed equilibrium, epistaxis, tinnitus

Endo: gynecomastia, hyperglycemia

GI: ↑liver enzymes, anorexia, constipation, diarrhea, dry mouth, dyspepsia, nausea, vomiting

GU: dysuria, nocturia, polyuria, sexual dysfunction, urinary frequency

Hemat: anemia, leukopenia, thrombocytopenia

Metab: ↑weight

MS: joint stiffness, muscle cramps

Neuro: abnormal dreams, anxiety, confusion, dizziness, drowsiness, dysgeusia, headache, nervousness, paresthesia, psychiatric disturbances, tremor, weakness

Resp: cough, dyspnea

Misc: gingival hyperplasia

Interactions ⬆ ⬇

Drug-drug:

Additive hypotension may occur when used concurrently with fentanyl, other antihypertensives, nitrates, acute ingestion of alcohol, or quinidine.
Antihypertensive effects may be ↓ by concurrent use of NSAIDs.
Concurrent use with beta blockers, digoxin, disopyramide, or phenytoin may result in bradycardia, conduction defects, or HF.

Grapefruit juice↑ serum levels and effect.

Route/Dosage ⬆ ⬇

PO (Adults ): 2.5 mg twice daily; may be ↑ every 2–4 wk by 5 mg/day (not to exceed 20 mg/day) .
PO (Children ): 0.15–0.2 mg/kg/day divided TID-QID initially; titrate at 2–4 wk intervals to a maximum dose of 0.8 mg/kg/day or 20 mg/day (whichever is lower).

Availability ⬆ ⬇

(Generic available)

Capsules: 2.5 mg; 5 mg

Assessment ⬆ ⬇

Monitor BP and pulse prior to and periodically throughout therapy. Monitor ECG periodically in patients receiving prolonged therapy.
Monitor intake and output ratios and daily weight. Assess patient for signs of HF (peripheral edema, rales/crackles, dyspnea, weight gain, jugular venous distention).
Assess for rash periodically during therapy. May cause Stevens-Johnson syndrome. Discontinue therapy if severe or if accompanied with fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, hepatitis and/or eosinophilia.
Angina: Assess location, duration, intensity, and precipitating factors of patient’s anginal pain.

Lab Test Considerations:

Total serum calcium concentrations are not affected by calcium channel blockers.
- Monitor serum potassium periodically. Hypokalemia increases risk of arrhythmias; should be corrected.
- Monitor renal and hepatic functions periodically during long-term therapy. Several days of therapy may cause increase in hepatic enzymes, which return to normal upon discontinuation of therapy.

Implementation ⬆ ⬇

PO: May be administered without regard to meals. May be administered with meals if GI irritation becomes a problem.

Patient/Family Teaching ⬆ ⬇

Advise patient to take medication as directed, even if feeling well. Take missed doses as soon as possible unless almost time for next dose; do not double doses. May need to be discontinued gradually.
Advise patient to avoid drinking grapefruit juice during therapy.
Caution patient to change positions slowly to minimize orthostatic hypotension.
May cause dizziness. Advise patient to avoid driving or other activities requiring alertness until response to the medication is known.
Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to avoid concurrent use of alcohol or OTC medications and herbal products, especially cold preparations, without consulting health care professional.
Caution patient to wear protective clothing and use sunscreen to prevent photosensitivity reactions.
Advise patient to notify health care professional if rash, irregular heartbeats, dyspnea, swelling of hands and feet, rash, pronounced dizziness, nausea, constipation, or hypotension occurs.
Advise patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.
Encourage patient to comply with other interventions for hypertension (weight reduction, low-sodium diet, smoking cessation, moderation of alcohol consumption, regular exercise, and stress management). Medication controls but does not cure hypertension.
- Instruct patient and family in proper technique for monitoring BP. Advise patient to take BP weekly and to report significant changes to health care professional.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇