Plasma contains glucose, protein, lipids, amino acids, electrolytes, minerals,
lactic and pyruvic acids, hormones, enzymes, oxygen, and carbon dioxide.
Blood provides nutrients including oxygen to body cells. Oxygen is carried in
the hemoglobin of red blood cells (RBCs). The white blood cells are the major
defense mechanism of the body and act by engulfing microorganisms. Platelets
are present in the blood. They gather at the site of a wound and aggregate (stitch
together) to form a clot to stop the bleeding.Cardiac drugs
Cardiac drugs regulate heart contraction, heart rate, and heart rhythm. Cardiac
drugs also regulate blood flow to the heart muscle. There are three groups of
cardiac drugs: glycosides, antianginals, and antidysthythmics.
Glycosides, known as digitalis glycosides, inhibit the sodium-potassium
pump and increase intracellular calcium. This causes the cardiac muscle fibers
to contract better. Glycosides have three effects on the heart:1.A positive inotropic action that increases cardiac muscle contraction.
2.Negative chronotropic action that decrease the heart rate.
3.A negative dromotropic action that decreases conduction of the electrical
stimulus.The effects of glycosides improve heart, peripheral, and kidney function
because- Cardiac output is increased.
- Preload is decreased, improving blood flow to the periphery and kidneys.
- Edema decreases.
- Fluid excretion increases.
- Fluid retention in the lung and extremities is decreased.
Glycoside preparations are also used to correct atrial fibrillation and atrial
flutter (cardiac dysrhythmia).
Glycosides include digoxin (Lanoxin), inamrinone lactate (Inocor) and mil-
rinone lactate (Primacor), and positive inotropic bipyridines. The antidote for
glycoside toxicity is digoxin immune Fab (Ovine, Digibind).
A list of drugs utilized in the treatment of the heart is provided in the
Appendix. Detailed tables show doses, recommendations, expectations, side(^350) CHAPTER 19 Cardiac Circulatory Medications