chapter 54 lehne drugs for angina pectoris

What is the primary action of nitroglycerin?

Decreases cardiac oxygen demand by dilating veins, reducing venous return, decreasing ventricular filling, and reducing wall tension (preload).

what are the vascular effects of nitroglycerin?

acts as venodialtor, Improves coronary artery blood flow

Dilates coronary arteries

Can slightly reduce afterload at high doses

how does nitroglycerin relive pain?

Relieves angina pain through effects on peripheral blood vessels

Works primarily by reducing the heart's workload rather than directly increasing coronary blood flow

How does nitroglycerin improve coronary artery blood flow?

By acting as a venodilator and dilating coronary arteries.

What is the mechanism by which nitroglycerin works in the body?

It converts to nitric oxide, activates guanylyl cyclase, and causes smooth muscle relaxation in blood vessels, resulting in vasodilation.

What is the onset and duration of sublingual nitroglycerin?

Onset is 1-3 minutes, and duration is up to 1 hour.

what is sublingual administration ideal for?

stopping acute angina attacks, short term prevention before exertion.

What is the purpose of transdermal nitroglycerin patches?

Used for sustained prophylaxis; applied once daily with a 10-12 hour 'patch-free' period. oneset is 30-60 mins and apply to hairless skin, rotate sites .

desription of sustained - release oral capsules

Used for long-term prophylaxis only

Take once or twice daily

Swallow capsules whole

Cannot stop acute attacks

Risk of tolerance development

What are the risks associated with intravenous (IV) nitroglycerin administration?

Requires frequent blood pressure monitoring (5-10 mins) and may need dose increases due to tolerance. its used in acute heart failure.

What major drug interactions should be considered with nitroglycerin?

Erectile dysfunction medications (e.g., sildenafil), blood pressure medications (e.g., beta-blockers, calcium channel blockers, ACE inhibitors, risk of additive hypotension affects) , other vasodilators, and alcohol. -> can enhance vasodilation and risk of orthostatic hypotension.

What are the cardiovascular effects of verapamil?

Blocks calcium channels, SA node - causing bradycardia, AV node - can casue partial/ complete AV block myocardium - decreased contractility, and vascular smooth muscle - vasodilation.

what are the pharmacokinestics of verapamil?

Can be given orally or IV

Oral absorption: 20% bioavailability

Onset: 30 minutes

Peak effect: 5 hours

Metabolized by liver

what are the precautions of verapamil?

Use cautiously in:

Cardiac failure

Patients taking β-blockers

Hepatic impairment

Contraindicated in:

Sick sinus syndrome

2nd or 3rd-degree AV block

What are the common side effects of verapamil?

Hypotension, peripheral edema, constipation, and potential increase in digoxin levels.

What is the preferred treatment for angina in asthma patients?

Calcium channel blockers (CCBs) and long-acting nitrates.

calcium channel blockers in treatment for angina in asthma patients

m Channel Blockers (CCBs)

First-line treatment choice

Do not cause bronchoconstriction

Particularly effective: dihydropyridines

long-acting nitrates in trating angina in asthma patients

Safe alternative

Can be used in combination with CCBs

Available as patches or oral formulations

What medications should be avoided in asthma patients with angina?

Beta-blockers, as they can promote bronchoconstriction.

if B-blockers must be used do what?

Choose beta-1 selective agents (like metoprolol)

Monitor closely for respiratory symptoms

Use lowest effective dose

Have rescue medications readily available

What types of calcium channel blockers are used in angina management?

Verapamil, diltiazem, and nifedipine (dihydropyridine-type).

What is the mechanism of action for calcium channel blockers in angina?

They block calcium channels in vascular smooth muscle, reducing peripheral resistance and increasing cardiac oxygen supply.

what is the inital approach for CCB

Consider as first-line if β-blockers contraindicated

Can be used alone or in combination therapy

what is the combination therapy for CCB?

With β-blockers: Choose dihydropyridine type

Avoid verapamil/diltiazem with β-blockers

Can combine with long-acting nitrates

What monitoring is required when using calcium channel blockers?

Blood pressure, heart rate, signs of peripheral edema, and symptoms of heart failure, AV conduction

What should patients be educated about when taking nitroglycerin?

To report dizziness/lightheadedness, monitor for ankle swelling, and maintain follow-up appointments.

What is the risk of tolerance development with sustained-release oral capsules of nitroglycerin?

They are used for long-term prophylaxis but cannot stop acute attacks.

What is the effect of alcohol on nitroglycerin?

It enhances vasodilation and increases the risk of orthostatic hypotension.

What are the ideal uses for sublingual nitroglycerin?

Stopping acute angina attacks and short-term prevention before exertion.

What is the onset and duration of transdermal nitroglycerin patches?

Onset is 30-60 minutes, and duration is up to 14 hours.