Drugs for Angina

Question 1

what is angina?

what 3 reasons can give rise to angina?

Answer 1

lack of blood to the myocardium

1. Coronary occlusion
2. Vasospastic/Variant angina
3. Unstable angina (platelet aggregation)

Question 2

what is classical angina?

when do symptoms occur?

Answer 2

• the coronary artery is narrowed.
• with increased emotional or physical exertion
  *

Question 3

What is Variant angina or Prinzmetal’s angina?

when do symptoms occur?

Answer 3

• Results from a reversible spasm of large coronary arteries, usually at the site of atherosclerotic plaque
• occur at rest or irrespective of the amount of physical or emotional exertion

Question 4

what is Acute coronary syndrome/Unstable angina?

when do you see symptoms?

Answer 4

• increased frequency and severity, as result of combination of atherosclerotic plaques and vasopasm.
• can occur even at rest. It might signal an impeding myocardial infarction and treated as a medical emergency

Question 5

What are the therapeutic strategies for treatment of angina? Mention the drugs utilized for each strategy.

Answer 5

1. increasing oxygen delivery - Nitrates & Calcium channel blockers
2. reducing oxygen requirement - Beta adrenergic blockers
3. Antiplatelet drugs - Low dose aspirin, abciximab
4. increase the efficiency of oxygen utilization by partial fatty acid oxidation inhibitors - Ranolazine

Question 6

what is preload?

what is afterload?

Answer 6

• amount of blood returning to the heart at the end of diastole
• the resistance against which the heart has to pump the blood during systole.

Question 7

what drugs are nitrates?

What are they?

how do they work?

do they cause muscle relaxation?

what determines their effectiveness?

Answer 7

• Nitroglycerine (GTN)
• Isosorbide dinitrate
• Isosorbide mononitrate
• they are powerful vasodilators
• they release Nitric oxide
• dont cause muscle relaxation
• Action on capacitance vessels to reduce cardiac pre-load

Question 8

nitrates have what bioavailability?

what is the mode of action of nitrates?

Answer 8

low bioavailability

it activates cGMP leading to smooth muscle relaxation

Question 9

which of the nitrate drugs is most commonly used?

what happens when the previous drug is given orally vs. sublingually?

Answer 9

Glyceryl trinitrate

orally = low bioavailability (very metabilized by liver)

sublingually = high bioavailability

Question 10

what is the effect of nitrates in the heart?

what other use, other than angina, are nitrates used for?

what will nitrate toxicity cause?

Answer 10

more decreased preload than decreased afterload

cyanide poisoning

• Severe headache
• Postural hypotension and reflex tachycardia
• Methemoglobinemia- caused by nitrites, not nitrates`

Question 11

nitrates will interact with which other?

Why?

Answer 11

sildenafil (viagra); because it inhibit a phosphodiesterase isoform (PDE5) that metabolizes cGMP in smooth muscle .

Question 12

what is the purpose of CCB in angina?

what are the CCB drugs for angina?

which of these drugs has a greater ratio of vascular smooth muscle effects than cardiac effects?

Answer 12

• to block voltage-gated L-type calcium channels in cardiac and smooth muscle.
  1. Dihydropyridines(DHP): Nifedipine, amlodipine, nicardipine, nimodipine
  2. Verapamil, diltiazem
• Dihydropyridines

Question 13

nimodipine is used for what other than angina?

Verapamil, diltiazem are used for what type of angina?

Answer 13

subarachnoid hemorrhage

block calcium-dependent conduction in the atrioventricular (AV) node and is used to treat AV nodal arrhythmias

Question 14

use of CCB’s in angina looks to produce what effect on the heart?

Answer 14

Decreased Preload + Decreased Afterload

(leads to decrease in oxygen demand and increase in oxygen supply)

Question 15

what is nifedipine?

what are the adverse effects of using this?

Answer 15

• mostly an arteriolar vasodilator and has minimal effect on cardiac conduction or HR
• flushing, headache, hypotension, peripheral edema

Question 16

What is the effect of verapamil?

what drug interaction does it have?

Answer 16

• Slows cardiac conduction, Decreases HR and O2 demand,Causes negative inotropic effect than nifedipine
• with digoxin, it will increase its levels

Question 17

what does Diltiazem do?

when is it used?

Answer 17

• Slows cardiac conduction, Decreases HR and O2 demand, Causes negative inotropic effect
• Particularly useful in variant angina

Question 18

What are the adverse reactions of CCB’s?

Answer 18

1. hypotension due to the vasodilatation
2. Peripheral edema
3. Over dose leads to cardiac arrest, bradycardia, atrioventricular block, and heart failure.

Question 19

how do beta blockers work in angina?

what is the effect in the heart?

when is it contraindicated?

They are mostly used for what?

Answer 19

• act by opposing the action of adrenaline on the heart because they block the β1 receptors present in the heart
• decrease heart rate, blood pressure, and contractility (decrease myocardial oxygen requirements)
• Vasospastic angina
• Effective in preventing exercise induced angina

Question 20

what is Ranolazine?

Primary mechanism of therapeutic action of ranolazine?

Answer 20

• pFOX inhibitor or partial fatty acid oxidation inhibitor in myocardium
• reduced contractility. This action results from blockade of a late sodium current