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Calcium Channel Blockers
amlodipine (Norvasc®):
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Adult (usual) Angina: 5-10 mg po qd. Hypertension initial: 5 mg po qd; maintenance 5-10 mg po qd. FDA labeled indications: Angina, stable or unstable; Hypertension. Small, fragile, or elderly individuals, or patients with hepatic insufficiency may be started on 2.5 mg once daily and this dose may be used when adding Norvasc® to other antihypertensive therapy. Titration: In general, titration should proceed over 7 to 14 days so that the physician can fully assess the patient's response to each dose level. [Supplied: 2.5, 5, 10mg tab]
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bepridil (Vascor®):
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Dosing: Adults: Oral: Initial:
200 mg/day, then adjust dose at 10-day intervals until optimal response
is achieved; usual dose: 300 mg/day; maximum daily dose: 400 mg Dosage adjustment in renal impairment: Risk of toxic reactions is greater in patients with renal impairment; dose selection should be cautious, usually starting at the low end of the dosage range Elderly: Peak concentrations and half-life are markedly increased in the elderly (>74 years); dose selection should be cautious, usually starting at the low end of the dosage range Supplied Tablet, as hydrochloride: 200 mg, 300 mg |
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diltiazem (Cardizem ®):
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Adult (usual) Oral: Angina: (regular release tablets) initial 30 mg po qid; usual dose 180-360 mg po daily (maximum 360 mg daily). Angina: (extended release capsule; Dilacor(R) XR), initial 120 mg po qd; usual dose 120-480 mg once daily, maximum 540 mg/day. Hypertension: (Cardizem SR), initial 60-120 mg po q12h.; usual dose 120-180 mg bid, maximum 360 mg/day. Hypertension: ( Dilacor(R) XR): initial, 120-240 mg orally once daily; titrate after 14 days; usual dose, 240-360 mg orally once daily, maximum 540 mg/day. Arrhythmia: (IV bolus), initial 0.25 mg/kg (or 20 mg) IV over 2 minutes; if inadequate response, may give second bolus 0.35 mg/kg (25 mg) after 15 min Arrhythmia: (IV continuous infusion), initial 5-10 mg/hr; increase in 5 mg/hr increments up to 15 mg/hr maintained for up to 24 hr.
Conversion from I.V. diltiazem to oral diltiazem: Start oral approximately 3 hours after bolus dose. Oral dose (mg/day) is approximately equal to [rate (mg/hour) x 3 + 3] x 10. 5 mg/hour = 180 mg/day; 7 mg/hour = 240 mg/day 11 mg/hour = 360 mg/day [Supplied: Immediate release tablets: 30, 60, 90, 120 mg. Sustained released capsules (SR): 60, 90, 120mg. Extended release capsules (CD): 120,180,240,300,360 mg. Vials (IV): 25, 50, 125 mg (5 mg/ml) ] |
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felodipine (Plendil®):
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CLINICAL PHARMACOLOGY - Mechanism of Action Felodipine is a member of the dihydropyridine class of calcium channel antagonists (calcium channel blockers). It reversibly competes with nitrendipine and/or other calcium channel blockers for dihydropyridine binding sites, blocks voltage-dependent Ca++ currents in vascular smooth muscle and cultured rabbit atrial cells, and blocks potassium-induced contracture of the rat portal vein. In vitro studies show that the effects of felodipine on contractile processes are selective, with greater effects on vascular smooth muscle than cardiac muscle. Negative inotropic effects can be detected in vitro, but such effects have not been seen in intact animals. The effect of felodipine on blood pressure is principally a consequence of a dose-related decrease of peripheral vascular resistance in man, with a modest reflex increase in heart rate. With the exception of a mild diuretic effect seen in several animal species and man, the effects of felodipine are accounted for by its effects on peripheral vascular resistance. Administration: avoid taking with grapefruit juice. Dose adjustments should be made at intervals of not less than 2 weeks. o not crush or chew extended release tablets; swallow whole. Dosage Adults: hypertension: Oral: 2.5-10 mg once daily; usual initial dose: 5 mg; increase by 5 mg at 2-week intervals, as needed; maximum: 10 mg Usual dose range (JNC 7) for hypertension: 2.5-20 mg once daily Elderly: Begin with 2.5 mg/day Dosing adjustment/comments in hepatic impairment: Initial: 2.5 mg/day; monitor blood pressure [Supplied 2.5 mg, 5 mg, 10 mg ER tab] |
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isradipine (Dynacirc®):
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CLINICAL PHARMACOLOGY Mechanism of Action Isradipine is a dihydropyridine calcium channel blocker. It binds to calcium channels with high affinity and specificity and inhibits calcium flux into cardiac and smooth muscle. The effects observed in mechanistic experiments in vitro and studied in intact animals and man are compatible with this mechanism of action and are typical of the class. Except for diuretic activity, the mechanism of which is not clearly understood, the pharmacodynamic effects of isradipine observed in whole animals can also be explained by calcium channel blocking activity, especially dilating effects in arterioles which reduce systemic resistance and lower blood pressure, with a small increase in resting heart rate. Although like other dihydropyridine calcium channel blockers, isradipine has negative inotropic effects in vitro, studies conducted in intact anesthetized animals have shown that the vasodilating effect occurs at doses lower than those which affect contractility. In patients with normal ventricular function, isradipine’s afterload reducing properties lead to some increase in cardiac output. Effects in patients with impaired ventricular function have not been fully studied. Clinical Effects Dose-related reductions in supine and standing blood pressure are achieved within 2-3 hours following single oral doses of 2.5 mg, 5 mg, 10 mg, and 20 mg DynaCirc® (isradipine), with a duration of action (at least 50% of peak response) of more than 12 hours following administration of the highest dose. DynaCirc® (isradipine) has been shown in controlled, double-blind clinical trials to be an effective antihypertensive agent when used as monotherapy, or when added to therapy with thiazide-type diuretics. During chronic administration, divided doses (b.i.d.) in the range of 5‑20 mg daily have been shown to be effective, with response at trough (prior to next dose) over 50% of the peak blood pressure effect. The response is dose-related between 5-10 mg daily. DynaCirc® (isradipine) is equally effective in reducing supine, sitting, and standing blood pressure. On chronic administration, increases in resting pulse rate averaged about 3-5 beats/min. These increases were not dose-related. Dosing: Hypertension: Oral: 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 (JNC 7): 2.5-10 mg/day in 2 divided doses. Note: Most patients show no improvement with doses >10 mg/day except adverse reaction rate increases; therefore, maximal dose in older adults should be 10 mg/day. Supplied Capsule (DynaCirc®): 2.5 mg, 5 mg Tablet, controlled release (DynaCirc® CR): 5 mg, 10 mg |
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nicardipine (cardene®):
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Clinical Pharmacology- MECHANISM OF ACTION Nicardipine inhibits the transmembrane influx of calcium ions into cardiac muscle and smooth muscle without changing serum calcium concentrations. The contractile processes of cardiac muscle and vascular smooth muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. The effects of nicardipine are more selective to vascular smooth muscle than cardiac muscle. In animal models, nicardipine produced relaxation of coronary vascular smooth muscle at drug levels which cause little or no negative inotropic effect Dosage Adults: Oral: Immediate release: Initial: 20 mg 3 times/day; usual: 20-40 mg 3 times/day (allow 3 days between dose increases). Sustained release: Initial: 30 mg twice daily, titrate up to 60 mg twice daily. Note: The total daily dose of immediate-release product may not automatically be equivalent to the daily sustained-release dose; use caution in converting. I.V. (dilute to 0.1 mg/mL): Acute hypertension: Initial: 5 mg/hour increased by 2.5 mg/hour every 15 minutes to a maximum of 15 mg/hour; consider reduction to 3 mg/hour after response is achieved. Monitor and titrate to lowest dose necessary to maintain stable blood pressure. Substitution for oral therapy (approximate equivalents): 20 mg every 8 hours oral, equivalent to 0.5 mg/hour I.V. infusion 30 mg every 8 hours oral, equivalent to 1.2 mg/hour I.V. infusion 40 mg every 8 hours oral, equivalent to 2.2 mg/hour I.V. infusion Dosing adjustment in renal impairment: Titrate dose beginning with 20 mg 3 times/day (immediate release) or 30 mg twice daily (sustained release). Specific guidelines for adjustment of I.V. nicardipine are not available, but careful monitoring/adjustment is warranted. Dosing adjustment in hepatic impairment: Starting dose: 20 mg twice daily (immediate release) with titration. Specific guidelines for adjustment of I.V. nicardipine are not available, but careful monitoring/adjustment is warranted. Supplied Capsule (Cardene®): 20 mg, 30 mg Capsule, sustained release (Cardene® SR): 30 mg, 45 mg, 60 mg Injection, solution (Cardene® IV): 2.5 mg/mL (10 mL) |
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nifedipine (Procardia®):
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CLINICAL PHARMACOLOGY Nifedipine is a calcium ion influx inhibitor (slow-channel blocker or calcium ion antagonist) which inhibits the transmembrane influx of calcium ions into vascular smooth muscle and cardiac muscle. The contractile processes of vascular smooth muscle and cardiac muscle are dependent upon the movement of extracellular calcium ions into these cells through specific ion channels. Nifedipine selectively inhibits calcium ion influx across the cell membrane of vascular smooth muscle and cardiac muscle without altering serum calcium concentrations. Mechanism of Action: The mechanism by which nifedipine reduces arterial blood pressure involves peripheral arterial vasodilatation and, consequently, a reduction in peripheral vascular resistance. The increased peripheral vascular resistance that is an underlying cause of hypertension results from an increase in active tension in the vascular smooth muscle. Studies have demonstrated that the increase in active tension reflects an increase in cytosolic free calcium. Nifedipine is a peripheral arterial vasodilator which acts directly on vascular smooth muscle. The binding of nifedipine to voltage-dependent and possibly receptor-operated channels in vascular smooth muscle results in an inhibition of calcium influx through these channels. Stores of intracellular calcium in vascular smooth muscle are limited and thus dependent upon the influx of extracellular calcium for contraction to occur. The reduction in calcium influx by nifedipine causes arterial vasodilation and decreased peripheral vascular resistance which results in reduced arterial blood pressure. Dosing: Oral: Adolescents and Adults: ( Note: When switching from immediate release to sustained release formulations, total daily dose will start the same) Initial: 30 mg once daily as sustained release formulation, or if indicated, 10 mg 3 times/day as capsules Usual dose: 10-30 mg 3 times/day as capsules or 30-60 mg once daily as sustained release Maximum dose: 120-180 mg/day Increase sustained release at 7- to 14-day intervals Dosing adjustment in hepatic impairment: Reduce oral dose by 50% to 60% in patients with cirrhosis. Supplied Capsule, liquid-filled: 10 mg, 20 mg Tablet, extended release: 30 mg, 60 mg, 90 mg Adalat® CC, Nifediac™ CC, Procardia XL®: 30 mg, 60 mg, 90 mg Afeditab™, Nifedical™ XL: 30 mg, 60 mg |
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nisoldipine (Sular®):
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CLINICAL PHARMACOLOGY Mechanism of Action Nisoldipine is a member of the dihydropyridine class of calcium channel antagonists (calcium ion antagonists or slow channel blockers) that inhibit the transmembrane influx of calcium into vascular smooth muscle and cardiac muscle. It reversibly competes with other dihydropyridines for binding to the calcium channel. Because the contractile process of vascular smooth muscle is dependent upon the movement of extracellular calcium into the muscle through specific ion channels, inhibition of the calcium channel results in dilation of the arterioles. In vitro studies show that the effects of nisoldipine on contractile processes are selective, with greater potency on vascular smooth muscle than on cardiac muscle. Although, like other dihydropyridine calcium channel blockers, nisoldipine has negative inotropic effects in vitro, studies conducted in intact anesthetized animals have shown that the vasodilating effect occurs as doses lower than those that affect cardiac contractility. The effect of nisoldipine on blood pressure is principally a consequence of a dose-related decrease of peripheral vascular resistance. While nisoldipine, like other dihydropyridines, exhibits a mild diuretic effect, most of the antihypertensive activity is attributed to its effect on peripheral vascular resistance. Adults: Oral: Initial: 20 mg once daily, then increase by 10 mg/week (or longer intervals) to attain adequate control of blood pressure; usual dose range (JNC 7): 10-40 mg once daily; doses >60 mg once daily are not recommended. A starting dose not exceeding 10 mg/day is recommended for the elderly and those with hepatic impairment. Supplied Tablet, extended release: 10 mg, 20 mg, 30 mg, 40 mg |
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verapamil (Isoptin ® )
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Adult (usual): Angina: (extended-release) initial: 180 mg po qd at bedtime. Titrate up to 480 mg at bedtime- maximum 540 mg at bedtime. (immediate release) initial: 80 mg po tid - may titrate at daily or weekly intervals to 360 mg daily. Arrhythmias, supraventricular: (immediate-release) initial: 240-320 mg po daily in 3-4 divided doses. Non-digitalized patients may require up to 480 mg daily in 3-4 divided doses. Arrhythmias, supraventricular: 5-10 mg IV (0.075-0.15 mg/kg) IV bolus over 2 min. May give additional 10 mg after 30 minutes if no response. Hypertension: (extended-release) initial, 180 mg tablet po qd at bedtime OR 200 mg capsule po qd at bedtime. Maintenance: titrate up to 480 mg TAB qd at hs or 400 mg capsule po qd at hs. Hypertension: (immediate-release) initial- 80 mg po tid. May titrate at daily or weekly intervals to 360-480 mg daily. Hypertension: (sustained-release) initial: 240 mg orally once daily in the morning. Maintenance (based on response): titrate up to 240 mg bid (tablet) or 480 mg (capsule) once a day in the morning. Migraine headache, prophylaxis: 80 mg po 3-4 times daily. [Supplied: Immediate release tablet: 40, 80, 120mg. Sustained release tablets (SR): 120, 180, 240 mg. Sustained released capsules (Verelan): 120,180,240,360mg. Covera HS (extended release tab): 180,240mg. Verelan PM (ER cap): 100,200,300mg. ] ----------------------------------- Dosing (Adults): Angina: Oral: Initial: 80-120 mg twice daily (elderly or small stature: 40 mg twice daily); range: 240-480 mg/day in 3-4 divided doses Hypertension: Oral: Immediate release: 80 mg 3 times/day; usual dose range (JNC 7): 80-320 mg/day in 2 divided doses. Sustained release: 240 mg/day; usual dose range (JNC 7): 120-360 mg/day in 1-2 divided doses; 120 mg/day in the elderly or small patients (no evidence of additional benefit in doses >360 mg/day). Extended release: Covera-HS®: Usual dose range (JNC 7): 120-360 mg once daily (once-daily dosing is recommended at bedtime) Verelan® PM: Usual dose range: 200-400 mg once daily at bedtime Arrhythmia (SVT): I.V.: 2.5-5 mg (over 2 minutes); second dose of 5-10 mg (~0.15 mg/kg) may be given 15-30 minutes after the initial dose if patient tolerates, but does not respond to initial dose; maximum total dose: 20 mg |
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Listed dosages are for - Adult patients ONLY. PLEASE READ THE
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any diagnosis or treatment made in reliance thereon. David F. McAuley, Pharm.D., R.Ph. GlobalRPh Inc. |
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