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CALCIUM CHANNEL BLOCKERS

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INOTROPIC AND CHRONOTROPIC

ACTIVITY

´ Calcium channel blockers decrease the force of

contraction of the myocardium (muscle of the

heart). This is known as the negative inotropiceffect of calcium channel blockers.

´ Calcium channel blockers also slow down the

conduction of electrical activity within the heart, by

blocking the calcium channel during the plateau

phase of the action potential of the heart This

results in a negative chronotropic effect

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MECHANISM OF ACTION

´ Calcium channel blockers work by blocking voltage-gated calcium channels in cardiac muscle and blood

vessels. This decreases intracellular calcium leading

to a reduction in muscle contraction.

´ In blood vessels, a decrease in calcium results in less

contraction of the vascular smooth muscle and

therefore an increase in arterial diameter (CCBs do

not work on venous smooth muscle), a phenomenoncalled vasodilation

´ With a relatively low blood pressure, the afterload on

the heart decreases.

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CLASSIFICATION

Dihydropyridine

´ They are often used to reduce systemicvascular resistance and arterial pressure,but are not used to treat angina because the

vasodilation and hypotension can lead toreflex tachycardia.

´ Dihydropiridine calcium channel blockerscan worsen proteinuria in patients with

nephropathy.

´ This CCB class is easily identified by thesuffix "-dipine".

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NON-DIHYDROPYRIDINE

´ P henylalkylamine

´ They are relatively selective for myocardium,

reduce myocardial oxygen demand and

reverse coronary vasospasm, and are often

used to treat angina.

´ They have minimal vasodilatory effects

compared with dihydropyridines and

therefore cause less reflex tachycardia´ Eg: Verapamil, Gallopamil

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BENZOTHIAZEPINE

´ They are an intermediate class betweenphenylalkylamine and dihydropyridines in their

selectivity for vascular calcium channels.

´ By having both cardiac depressant and

vasodilator actions, benzothiazepines are able to

reduce arterial pressure without producing the

same degree of reflex cardiac stimulation caused

by dihydropyridines.

Eg: Diltiazem

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INDICATIONS

´ High blood pressure

´ Angina

´ Abnormal heart rhythms

´ Pulmonary hypertension

´ Raynaud's syndrome

´ Cardiomyopathy

´ Subarachnoid hemorrhage.

´ Prevention of migraine headaches.

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AMLODIPINE

´ GENERIC NAME : Amlodipine

´ TRADE NAME : Norvasc

ACTION

´ Inhibits the transport of calcium into myocardial andvascular smooth muscle cells, resulting in inhibitionof excitation-contraction coupling and subsequentcontraction

´ Systemic vasodilation resulting in decreased bloodpressure

´ Coronary vasodilation resulting in decreasedfrequency and severity of attacks of angina

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INDICATIONS

Alone or with other agents in the management of hypertension, angina pectoris, and vasospastic(Prinzmetal's) angina

´ PHARMACOKINETICS

Absorption: Well absorbed after oral administration(64-90%)Distribution: Probably crosses the placenta

Protein Binding: 95-98%Metabolism and Excretion: Mostly metabolized bythe liverHalf-life: 30-50 hr (increased in geriatric patients

and patients with hepatic impairment

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CONTRAINDICATIONS

´ Hypersensitivity´ Blood pressure <90 mmHg

Use Cautiously in:

´ Severe hepatic impairment (dosage reductionrecommended)

´ Geriatric patients (dosage reductionrecommended; increased risk of hypotension)

´ Aortic stenosis

´ History of CHF

´ Pregnancy, lactation, or children (safety notestablished)

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ADVERSE REACTIONS

CentralNervous System: headache, dizziness,

fatigue,

Cardio Vascular : peripheral edema, angina,

bradycardia, hypotension, palpitations,

Gastro Intestinal: gingival hyperplasia, nausea,

Dermatology: flushing

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NURSE¶S RESPONSIBILTY

´ Monitor blood pressure and pulse before therapy, during dose titration, and periodically during therapy. Monitor ECGperiodically during prolonged therapy

´ Monitor intake and output ratios and daily weight. Assessfor signs of CHF (peripheral edema, rales/crackles,dyspnea, weight gain, jugular venous distention)

´ May be administered without regard to meal

´ Angina: Assess location, duration, intensity, andprecipitating factors of patient's anginal pain

´ Lab T est Considerations: Total serum calcium

concentrations are not affected by calcium channelblockers

´ Advise patient to take medication as directed, even if feeling well. Take missed doses as soon as possible unlessalmost time for next dose; do not double doses. May need

to be discontinued gradually

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VERAPAMIL

´ GENERIC NAME : Verapamil

´ TRADE NAME : Calan, Calan SR, Isoptin

ACTION´ Inhibits the transport of calcium into myocardial

and vascular smooth muscle cells, resulting in

inhibition of excitation-contraction coupling and

subsequent contraction

´ Decreases SA and AV conduction and prolongs

AV node refractory period in conduction tissue

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INDICATIONS

´ Management of hypertension, angina pectoris,and/or vasospastic (Prinzmetal's) angina

´ Management of supraventricular arrhythmias andrapid ventricular rates in atrial flutter or fibrillation

´ PHARMACOKINE

T IC S

Absorption: 90% absorbed after oral administration,but much is rapidly metabolized, resulting inbioavailability of 20-25%

Distribution: Small amounts enter breast milkProtein Binding: 90%Metabolism and Excretion: Mostly metabolized by theliver

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CONTRAINDICATIONS/PRECAUTIONS

´ Hypersensitivity

´

Sick sinus syndrome´ 2nd- or 3rd-degree AV block (unless an

artificial pacemaker is in place)

´ BP <90 mmHg

´ CHF, severe ventricular dysfunction, orcardiogenic shock, unless associated withsupraventricular tachyarrhythmias

´ Concurrent IV beta blocker therapy

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ADVERSE REACTIONS

Central Nervous System: abnormal dreams, anxiety,

confusion, dizziness/lightheadedness, drowsiness,headache, jitteriness, nervousness, psychiatricdisturbances, weakness,Eye, ENT: blurred vision, disturbed equilibrium,

epistaxis, tinnitus,Respiratory : cough, dyspnea, shortness of breath,Cardio Vascular : arrhythmias, CHF, bradycardia,chest pain, hypotension, palpitations, peripheral

edema, syncope, tachycardia,Gastro Intestinal : abnormal liver function studies,anorexia, constipation, diarrhea, dry mouth,dysgeusia, dyspepsia, nausea, vomiting,

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CONT¶D«.

Genito Urinary : dysuria, nocturia, polyuria, sexualdysfunction, urinary frequency,

Dermatology: dermatitis, erythema multiforme,

flushing, increased sweating, photosensitivity,pruritus/urticaria, rash,

Endocrine: gynecomastia, hyperglycemia,

Hematology: anemia, leukopenia,

thrombocytopenia,

Metabolic: weight gain,

MusculoSkeletal : joint stiffness, muscle cramps,

Neurology: paresthesia, tremor

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ROUTE AND DOSAGE

Oral : 80-120 mg 3 times daily, increased asneeded. Extended-release preparations--120-240mg/day as a single dose; may be increased as

needed (range 240-480 mg/day)´ Intra Venous (Adults ): 5-10 mg (75-150 mcg/kg);

may repeat with 10 mg (150 mcg/kg) after 15-30minAVAILABILITY

´ T ablets: 40 mg, 80 mg, 120 mg

´ Injection: 2.5 mg/m in 2- and 4-ml vials,

ampules, and syringes

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NURSE¶S RESPONSIBILITY

´ Monitor blood pressure and pulse before therapy, during dosage titration, and periodically throughout therapy. MonitorECG periodically during prolonged therapy. Verapamil maycause prolonged PR interval

´ Monitor intake and output ratios and daily weight. Assess for

signs of CHF

´ Angina: Assess location, duration, intensity, and precipitating

factors of patient's anginal pain

´ Arrhythmias: Monitor ECG continuously during administration.Notify physician promptly if bradycardia or prolonged

hypotension occurs. Emergency equipment and medicationshould be available. Monitor blood pressure and pulse beforeand frequently during administration

´ Lab T est Considerations: Total serum calcium concentrationsare not affected by calcium channel blockers

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CONT¶D«.

´ Monitor serum potassium periodically. Hypokalemia

increases the risk of arrhythmias and should becorrected

´ Monitor renal and hepatic functions periodicallyduring long-term therapy. May cause increase inhepatic enzymes after several days of therapy, whichreturn to normal on discontinuation of therapy

´ Do not confuse verapamil with Virilon (testosterone).Do not confuse Covera (verapamil) with Provera(medrosyprogesterone)

´ Oral: Administer verapamil with meals or milk tominimize gastric irritation

´ IntraVenous: Patients should remain recumbent for atleast 1 hr after IV administration to minimize

hypotensive effects

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DILTIAZEM

´ GENERIC NAME : diltiazemTRADE NAME : Cardizem

´ MODE OF ACTION

´ Inhibits transport of calcium into myocardialand vascular smooth muscle cells, resulting ininhibition of excitation-contraction coupling andsubsequent contraction

´ Systemic vasodilation resulting in decreasedblood pressure

´ Coronary vasodilation resulting in decreasedfrequency and severity of attacks of angina

´

Suppression of arrhythmias

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INDICATIONS

´ Hypertension

´ Angina pectoris and vasospastic (Prinzmetal's) angina

´ Supraventricular tachyarrhythmias and rapid ventricular rates in atrial flutter or

fibrillation

´ Management of Raynaud's syndrome

PHARMACOKINETICS

Absorption: Well absorbed, but rapidly metabolized after oral administration

Distribution: Unknown

Protein Binding: 70-80%

Metabolism and Excretion: Mostly metabolized by the liver (CYP 3A4 enzyme system)

Half-life: 3.5-9 hr

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CONTRAINDICATIONS

´ Hypersensitivity

´ Sick sinus syndrome

´ 2nd- or 3rd-degree AV block (unless anartificial pacemaker is in place)

´ Blood pressure <90 mmHg

´

Recent MI or pulmonary congestion´ Concurrent use of rifampin

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ADVERSE REACTIONS

Central Nervous System: abnormal dreams, anxiety, confusion, dizziness,

drowsiness, headache, nervousness, psychiatric disturbances,

weakness,

Eye ENT: blurred vision, disturbed equilibrium, epistaxis, tinnitus,

Respiratory : cough, dyspnea,

CarddioVascular : ARRHYTHMIAS, CHF, peripheral edema, bradycardia,

chest pain, hypotension, palpitations, syncope, tachycardia,

Gastro Intestinal : abnormal liver function studies, anorexia, constipation,

diarrhea, dry mouth, dysgeusia, dyspepsia, nausea, vomiting,

Genito Urinary : dysuria, nocturia, polyuria, sexual dysfunction, urinary

frequency

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CONT¶D«««

Dermatology : dermatitis, erythemamultiforme, flushing, increased sweating,

photosensitivity, pruritus/urticaria, rash,

Endocrine : gynecomastia, hyperglycemia,

Hematology: anemia, leukopenia,

thrombocytopenia,

Metabolic : weight gain,

MusculoSkeletal : joint stiffness, musclecramps,

Neuroolgy : paresthesia, tremor,

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ROUTE AND DOSAGE

Oral : 30-120 mg 3-4 times daily or 60-120 mg twice dailyas SR capsules or 180-240 mg once daily as CD or XRcapsules or LA tablets (up to 360 mg/day)

´

IntraVenous : 0.25 mg/kg; may repeat in 15 min with adose of 0.35 mg/kg. May follow with continuousinfusion at 10 mg/hr (range 5-15 mg/hr) for up to 24 hr

AVAILABILITY

´ T ablets: 30 mg, 60 mg, 90 mg, 120 mg

´ Injection: 5 mg/ml in 10-ml vials, 25 mg ready-to-usesyringes (Lyo-Ject)

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NURSE¶S RESPONSIBILITY

´ Monitor blood pressure and pulse before therapy,

during dose titration, and periodically during therapy.Monitor ECG periodically during prolonged therapy.May cause prolonged PR interval

´ Monitor intake and output ratios and dailyweight.Assess for signs of CHF (peripheral edema,rales/crackles, dyspnea, weight gain, jugular venousdistention)

´ Arrhythmias: Monitor ECG continuously during administration. Report bradycardia or prolonged

hypotension promptly. Emergency equipment andmedication should be available. Monitor bloodpressure and pulse before and frequently during administration

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CONT¶D«.

´ Lab T est Considerations: Total serum calciumconcentrations are not affected by calcium channelblockers

´ Monitor serum potassium periodically. Hypokalemia

the risk of arrhythmias and should be corrected´ Monitor renal and hepatic functions periodically

during long-term therapy. May cause in hepaticenzymes after several days of therapy, which returnto normal on discontinuation of therapy

´ Do not confuse Cardizem (diltiazem) with Cardene(nicardipine). Do not confuse Cardizem LA withCardene SR

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THANK YOU

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