Drugs for Ischemic Heart Disease class notes

Flashcards about drugs used to treat ischemic heart disease.

Ischemic Heart Disease

Insufficient oxygen to heart muscle.

Pharmacological Agents for Ischemic Heart Disease

Beta Blockers, Nitrates, and Calcium Channel Blockers

What are the effects of Beta Blockers?

Decrease myocardial oxygen demand and reduce angina symptoms.

Where are Beta 1 adrenergic receptors located?

Cardiac sarcolemma

Where are Beta 2 receptors located?

Bronchial and vascular smooth muscle

Where are Beta 3 receptors located?

Endothelial tissue

What are the effects of Beta Blockers?

Negative inotropic (lowers contractility), negative chronotropic (lowers rate), lowers myocardial oxygen consumption.

Mechanism of action of Beta Blockers

Prevents epinephrine and norepinephrine from binding to receptors, inhibition of SA node/AV node, shortens myosin and actin interaction, switches myocardial metabolism from fatty acids to glucose.

Plasma Half Life

Amount of time for 50% of drug concentration to disappear from plasma.

Protein Binding

Extent at which drug binds to plasma proteins, especially albumin and alpha-1-acid glycoprotein (only unbound medication is active).

First Pass Hepatic Metabolism

Substance enters portal vein from GI system, liver removes substance effectively stopping distribution.

Non-Cardio-Selective Beta Blockers

Medications that affect the heart and respiratory system.

Cardio-Selective Beta Blockers

Medications that target cardiac Beta 1 receptors.

Vasodilatory Non-Selective Beta Blockers

Works on heart and dilates blood vessels.

Vasodilatory Selective Beta Blockers

Selective for Beta 1 receptors and vasodilates through different pathway.

Hydrophilic Beta Blockers

Excreted by kidneys

Lipophilic Beta Blockers

Metabolized by liver, more prone to interactions

Clinical Indications for Beta Blockers

Angina Pectoris, Acute Coronary Syndromes, CVA, Vascular Surgery

Angina Pectoris

Inadequate coronary vasodilation, increased myocardial oxygen demand. Any beta blocker will work in the absence of other diseases.

Acute Coronary Syndromes Management

Anti-thrombolytic therapy. In hospital quadruple therapy includes beta blockers, statins, ACE inhibitors and antiplatelet therapies.

Acute ST Elevation MI indications

Ongoing chest pain, tachycardia, hypertension, ventricular arrhythmias.

CVA Treatment

B1 selective agents shown to reduce stroke. Non-selective propranolol modestly useful.

Vascular Surgery and Beta Blockers

Protective effect, death from cardiac causes and MI reduced. Not helpful for low cardiac risk patients.

Cardiac Contraindications for Beta Blockers

Severe bradycardia, high degree heart block, cardiogenic shock, untreated LV failure

Pulmonary Contraindications for Beta Blockers

Severe asthma or bronchospasm. Mild asthma or bronchospasm.

Organic Nitrates

1st line agents for angina; reduce myocardial oxygen demand; vasodilator; increases cyclic guanosine monophosphate.

Examples of Organic Nitrates

Glyceryl Trinitrate, Isosorbide Dinitrate

Clinical Actions of Organic Nitrates

Reduces preload due to vasodilation and decreased venous return, reduces afterload due to vasodilation, improves coronary perfusion (more direct effect), reduced renal and visceral perfusion.

Absorption of Organic Nitrates

Administered sublingually due to high first pass metabolism. Short half life. Too much use can create tolerance.

Indications for Organic Nitrates

Angina, MI and acute coronary syndromes, esophageal spasm.

Contraindications for Organic Nitrates

Viagra, Cialis, Hypotension, Hypovolemia, Constrictive Pericarditis

Side Effects of Organic Nitrates

Headache, hypotension, tachycardia, facial flushing.

Calcium Channel Blockers

Calcium sustains contraction; increases interaction of myosin and actin; calcium channel blockers inhibit movement of calcium ions into cells.

Mechanism of Action of Calcium Channel Blockers

Bind to L-type calcium channels. L-type calcium channels are found on cardiomyocyte surfaces and blood vessels.

Dihydropyridines

Affect blood vessels, used to control blood pressure, relaxes smooth muscle, widens vessel.

Non-Dihydropyridines

Affect the heart, reduce contractility, slow heart rate, reduce conduction rate.

Indications for Calcium Channel Blockers

Angina, high blood pressure.

Contraindications for Calcium Channel Blockers

Heart failure, hypotension, heart block, sick sinus syndrome, drug interactions.

Adverse Reactions to Calcium Channel Blockers

Fatigue/dizziness, heart failure, edema.

Potassium Channel Openers

Influx of potassium into cells; arterial and venous dilation; increase in coronary blood flow; cardioprotective-prevents vascular occlusion.

Mechanism of Action of Potassium Channel Openers

Targets ATP sensitive potassium channels in plasma membrane of cell; decrease in membrane potential (hyperpolarization); reduces calcium entry.

Ranolazine

Sodium channel blocker, prevent sodium influx, indirectly prevents calcium influx.

Trimetazidine

Non-hemodynamic mechanisms, enhances glucose metabolism, patients who are unresponsive to long-acting nitrates and CCB’s.