calcium channel blockers
Hypertension (as monotherapy or in combination with other antihypertensives).
Inhibits the transport of calcium into myocardial and vascular smooth muscle cells, resulting primarily in peripheral arterial vasodilation.
Reduction in blood pressure.
Absorption: Well absorbed after oral administration (64–90%).
Protein Binding: 93%.
Metabolism and Excretion: Mostly metabolized by the liver; primarily excreted in urine (10% as unchanged drug).
Half-life: 30–50 hr.
TIME/ACTION PROFILE (plasma concentrations)
Use Cautiously in:
- Aortic stenosis;
- Severe obstructive coronary artery disease (↑ risk of worsening angina or MI)
- Severe hepatic impairment
- OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk
- Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
- Pedi: Children <6 yr (safety and effectiveness not established);
- Geri: ↑ risk of hypotension in older adults (dose ↓ recommended) .
Adverse Reactions/Side Effects
CNS: dizziness, drowsiness
CV: peripheral edema, palpitations
GI: abdominal pain, nausea
* CAPITALS indicate life-threatening.
Underline indicate most frequent.
- Strong CYP3A4 inhibitors, including ketoconazole, itraconazole, clarithromycin, and ritonavir may ↑ levels and risk of toxicity.
- Additive hypotension may occur when used concurrently with other antihypertensives, nitrates, acute ingestion of alcohol, or sildenafil.
- ↑ risk of myopathy with simvastatin (do not exceed 20 mg/day of simvastatin).
- May ↑ cyclosporine and tacrolimus levels.
PO (Adults): 2.5–5 mg once daily.
PO (Adults >65 yr): Initiate at 1.25 mg once daily, ↑ as required/tolerated (up to 5 mg/day).
PO (Children ≥6 yr): 1.25–2.5 mg once daily.
PO (Adults): Initiate at 1.25 mg once daily, ↑ as required/tolerated (up to 5 mg/day).
Tablets: 2.5 mg, 5 mg
- Monitor BP and pulse before therapy, during dose titration, and periodically during therapy. Titration usually occurs after 7–14 days.
- Monitor frequency of prescription refills to determine adherence.
Lab Test Considerations:
Total serum calcium concentrations are not affected by calcium channel blockers.
- Administer once daily.
- Instruct patient to take medication as directed, even if feeling well. Advise patient to read Patient Information before starting therapy and with each Rx refill in case of changes.
- May cause drowsiness or dizziness. Advise patient to avoid driving or other activities requiring alertness until response to the medication is known.
- 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.
- Advise patient to notify health care professional if irregular heartbeats, dyspnea, swelling of hands and feet, pronounced dizziness, nausea, feeling faint or lightheaded occurs.
- Advise patient to notify health care professional immediately if worsening chest pain or heart attack occurs.
- Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken, to avoid alcohol, and to consult health care professional before taking any new medications, especially cold preparations and NSAIDs.
- Advise patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.
Decrease in BP.
Davis’s Drug Guide for Nurses App + Web from F.A. Davis and Unbound Medicine covers 5000+ trade name and generic drugs. Includes App for iPhone, iPad, and Android smartphone + tablet. Handbook covers dosage, side effects, interactions, uses. Davis Drug Guide PDF. Complete Product Information.