Beta Blocker Special Considerations
Pulmonary disease-->Bronchospasm
Diabetes mellitus (DM), may mask symptoms of hypoglycemia
Thyrotoxicosis may mask symptoms of tachycardia and elevated blood pressure
Advanced age, older adults have increased sensitivity to beta blockers, therefore, start
low and go slow.
Beta Blockers Contraindications
Uncompensated heart failure
Pulmonary edema
Bradycardia, heart block or sick sinus syndrome (in the absence of a pacemaker)
labetalol and carvedilol
3rd generation; block α-adrenergic receptors in addition to β receptors; can dilate blood
vessels and cause postural hypotension.
Calcium Channel Blockers
-Promotes relaxation of peripheral arterioles resulting in a decreased afterload which
reduces cardiac oxygen demand.
-Blocks calcium channels in the heart and vascular smooth muscle;
-dihydropyridines, for which nifedipine is the prototype.
-nondihydropyridines, includes the drugs: verapamil and diltiazem.
Nondihydropyridine
Affects the Heart and Arteriole Blood Vessels; Verapamil/Diltiazem
Arteriole Dilation;
Slower conduction AV/SA node;
Decrease cardiac contractility
Dihydropyridine
,Acts Mainly on Arteriole Blood Vessels; Nifedipine
Does not effect heart muscle directly and therefore no AE as that of Verapamil/Diltiazem
Verapamil Effects
Blockade at peripheral arterioles causes dilation and thereby reduces arterial pressure.
• Blockade at arteries and arterioles of the heart increases coronary perfusion.
• Blockade at the SA node reduces heart rate.
• Blockade at the AV node decreases AV nodal conduction.
• Blockade in the myocardium decreases force of contraction
Verapamil Therapeutic Uses
Angina pectoris; Essential hypertension; Cardiac dysrhythmias
Verapamil Adverse Effects
Constipation; dizziness, facial flushing, headache, and edema of the ankles and feet
Calcium Channel Blockers Cardiac Adverse Effects
SA Node block->bradycardia;
AV Node Block>partial/complete AV block; Myocardium>decrease contractility;
Verapamil/Diltiazem Drug Contraindication
-Digoxin; increase risk of AV block and raises plasma digoxin levels when combined:
-β-adrenergic blocking agents due to similar effects of decrease heart rate, AV
conduction, and contractility
Verapamil/Diltiazem Food Contraindication
Grapefruit juice can inhibit the intestinal and hepatic metabolism of many drugs and
thus raise their levels.
Diltiazem Actions and Uses
-blocks calcium channels in the heart and blood vessels;
-lower blood pressure through arteriolar dilation;
-used for angina pectoris, essential hypertension, and cardiac dysrhythmias
Verapamil/Diltiazem Pharmacokinetics
Orally well absorbed and then extensively metabolized on its first pass through the liver;
bioavailability is only about 50%
Verapamil and Diltiazem High Risk Patients
, CONTRINDICATED in patients with hypotension, sick sinus syndrome, and second- or
third-degree atrioventricular block.
Verapamil and Diltiazem Therapeutic Indication
hypertension, angina, and cardiac dysrhythmias.
Verapamil and Diltiazem Monitoring
No routine blood monitoring required.
Nifedipine
-Dihydropyridine;
-blocks calcium channels in VSM of arteriole; promotes vasodilation;
-produces very little blockade of calcium channels in the heart
Nifedipine Indication
HTN; Angina; Not indicated for cardiac dysrhythmias
Nifedipine Adverse Effects
No heart specific effects; edema, flushing, headache, dizziness reflex tachycardia
AE: Secondary to arteriole vasodilation
Dihydropyridines/Nifedipine Therapeutic Goal
approved for essential hypertension and angina
Dihydropyridines/Nifedipine High Risk Patients
hypotension, use cautiously w/ sick sinus syndrome, heart failure, and second- or third-
degree atrioventricular block.
Dihydropyridines/Nifedipine Adverse Effects
Reflex tachycardia can be suppressed with a β blocker. Peripheral edema can be
reduced with a diuretic
Nifedipine Pharmacokinetics
well absorbed after oral administration but undergoes extensive first-pass metabolism;
only about 50% of an oral dose reaches the systemic circulation.
Calcium Channels Blockers Contraindications
systolic blood pressure < 90 mm Hg
sick sinus syndrome
recent myocardial infarction (MI) or pulmonary congestion