Why does angina pain occur? 

When cardiac oxygen supply is insufficient to oxygen demand

What determines cardiac oxygen demand?

• HR
• contractility
• preload
• afterload

What determines cardiac oxygen supply?

• myocardial blood flow

Name two types of angina pectoris

1. Stable angina
2. Unstable angina

Describe stable angina

• caused by coronary artery atheroschlerosis- artery that is only partially occluded by plaque
• pain is brought on by physical activity, emotional excitement, large meals, and cold exposure
• predictable
• can progress to unstable angina

What is the treatment strategy for anginal pain?

the goal is to reduce the intensity and frequency of anginal attacks by decreasing cardiac oxygen demand with drugs that:

• decrease HR
• decrease contractility
• decrease afterload
• decrease preload

Name the three type of drugs for treatment for treatment of angina 

• organic nitrates (Nitroglycerin)
• beta blockers (propranolol)
• calcium channel blockers (verapamil, nifedipine)

What is the drug of choice for relieving acute anginal attacks?

Nitroglycerin

What are the therapeutic effects of nitroglycerin?

Nitroglycerin acts directly on vascular smooth muscle (VSM) to promote VASODILATION, primarily on veins; dilation of arterioles is only modest.

To cause vasodilation, nitroglycerin must first be converted to nitric oxide, its active form. This requires the presence of a sulfhydryl source.

How does nitroglycerin relieve pain of stable angina?

How is nitroglycerin administered?

How is it metabolized?

Nirtoglycerin is highly lipid soluble and crosses membranes with ease therefore it can be given:

sublingual, buccal, transdermal, oral, IV, spray

It is metabolized by rapid inactiviation by hepatic enzymes. It's half life is only 5-7 minutes and each dose is destroyed on its first pass through the liver

Adverse effects of nitroglycerin

generally well tolerated

• Headaches which usually diminishes after the first few weeks of treatment
• Orthostatic hypotension
• Reflex tachycardia- baroreceptor reflex is activated by the decrease of BP, thereby causing sympathetic stimulation to the heart →causing increase in HR and contractile force →increasing oxygen demand, negating therapeutic benefits. Pretreatment with a Beta Blocker or verapamil (CCB) can prevent sympathetic cardiac stimulation

Drug interaction with Nitroglycerin

Nitroglycerin can intensify the effects of other hypotensive meds. Therefore care should be taken when nitro is given with beta blocker, calcium channel blockers, diuretics, and all other meds that lower BP. Patients should avoid alcohol

How to prevent Nitroglycerin tolerance

Tolerance can develop rapidly (over one day). To prevent tolerance, nitro should be given

• at the lowest effective dose
• long acting formulas (patches & SR)
• used on an intermittent schedule that allows for 8 hours drug-free daily, usually at night

Protocal for terminating an anginal attack with sublingual nitroglycerin

• administer as soon as pain begins
• if pain is not relieved in 5 minutes, call 911
• while waiting take 1 more tablet, and then a 3rd 5 minutes later

Nitroglycerin teaching points?

• nitroglycerin tabs formulates for sublingual use are ineffective if swallowed
• store in a tightly closed, dark container and tablets can remain effective for 24 months after first opened
• after 24 months throw away

Which medication is the first line drug for stable angina to ↓ oxygen demand by ↓ HR, contractility, and afterload?

Beta Blockers

How does the administration of Beta Blockers differ from Nitroglycerin?

Beta Blockers are given on a fixed schedule, not PRN

What are the therapeutic effects of Beta Blocker?

Beta Blockers reduce anginal pain by

1.  ↓ cardiac oxygen demand by blocking beta₁ receptors in the heart, which ↓HR, contractility, which results in reduction of arterial pressure (afterload)
2. Also help ↑ O₂ by slowing HR →increases time in diastole → increases time during which blood flows through myocardial vessels

Dosing concerns for Beta Blockers

• dosage should be low initially and then gradually increased
• dosing goal is to reduce HR 50 to 60 BPMand limit exertional HR to 100 BPM
• Beta blockers should not be removed abruptly, doing so ↑ incidence & intensity of anginal attacks and may even precipitate MI

Adverse effects of beta blockers

• hypotension
• ↓ HR
• ↓ contractility
• Fatigue
• depression
• insomnia

What are the therapeutic effects of Calcium Channel Blockers?

Calcium Channel Blockers ↓ stable angina pain by:

relaxing peripheral arterioles, which results in a decrease in afterload and a reduction in cardiac O₂ demand

What are the adverse effects of Calcium Channel Blockers?

• hypotension, which can induce
• reflex tachycardia

Name three of the most common Calcium Channel Blockers

1. verapamil
2. diltiazem
3. nifedipine