A nurse is caring for a client who is prescribed tetracycline 5 grams daily PO in divided doses every 8 hr. Available is tetracycline 500 mg capsules. How many capsules should the nurse administer per dose? (Round the answer to the nearest tenth. Use a leading zero if it applies. Do not use a trailing zero.)

A. ALT & AST:
ALT (alanine aminotransferase) and AST (aspartate aminotransferase) are liver enzymes that are typically used to assess liver function and detect liver damage. Epoetin alfa (Epogen) is a medication used to stimulate red blood cell production in patients with anemia, particularly in those with chronic renal disease. While liver function may be important in overall health monitoring, ALT and AST levels are not directly relevant to evaluating the effectiveness of epoetin alfa therapy.

B. Leukocyte count:
Leukocyte count measures the number of white blood cells and is used to assess immune function or detect infections. Epoetin alfa does not have a direct effect on white blood cell production, and therefore, monitoring the leukocyte count is not the best indicator for determining the effectiveness of epoetin alfa therapy, which is primarily concerned with red blood cell production.

C. Hemoglobin & hematocrit:
Epoetin alfa (Epogen) is used to stimulate the production of red blood cells and treat anemia, particularly in patients with chronic kidney disease or those undergoing chemotherapy. The therapeutic effectiveness of epoetin alfa is most commonly assessed by monitoring the hemoglobin and hematocrit levels, as these are direct indicators of red blood cell count and oxygen-carrying capacity. An increase in these values suggests that the medication is effective in treating anemia.

D. Clotting Factors:
Clotting factors are proteins in the blood that help control bleeding. While epoetin alfa can increase red blood cell production, it is not directly associated with changes in clotting factors. In fact, there is a potential risk of increased thromboembolic events (e.g., blood clots) with epoetin alfa, particularly if hemoglobin levels rise too rapidly, but monitoring clotting factors is not the primary way to assess the drug's effectiveness. Monitoring hemoglobin and hematocrit levels is the more appropriate strategy.

A) Fluoroquinolones:
Fluoroquinolones, such as levofloxacin and ciprofloxacin, are known to potentially cause QT prolongation, which can increase the risk of serious arrhythmias, including torsades de pointes. The mechanism by which fluoroquinolones cause QT prolongation involves inhibition of the hERG potassium channels, which delays repolarization of the heart, leading to a longer QT interval. Clinicians should be cautious when prescribing fluoroquinolones, particularly in patients with known risk factors for QT prolongation, such as electrolyte imbalances or a history of cardiac arrhythmias.

B) Macrolides:
Macrolides, including drugs like azithromycin, clarithromycin, and erythromycin, are also associated with an increased risk of QT prolongation. Like fluoroquinolones, they can interfere with cardiac repolarization by inhibiting potassium channels. The risk of QT prolongation with macrolides is particularly concerning in individuals with pre-existing heart conditions, those on other QT-prolonging drugs, or patients with electrolyte disturbances. It is important to monitor these patients closely for any signs of arrhythmias.

C) Cephalosporins:
Cephalosporins, which are a class of beta-lactam antibiotics, are not commonly associated with QT prolongation. While cephalosporins can cause other side effects, such as allergic reactions, gastrointestinal disturbances, or potential nephrotoxicity, they do not typically affect the heart's electrical conduction system in the same way that fluoroquinolones and macrolides do. Thus, QT prolongation is not a major concern with cephalosporins.

D) Penicillins:
Penicillins, another class of beta-lactam antibiotics, are not known to cause QT prolongation. Like cephalosporins, they are generally considered safe with respect to cardiac effects. While penicillins may cause allergic reactions or gastrointestinal side effects, they do not typically impact the QT interval. Therefore, QT prolongation is not a significant adverse effect of penicillins.

E) Tetracyclines:
Tetracyclines, including drugs like doxycycline and tetracycline, are not generally associated with QT prolongation. These antibiotics work by inhibiting bacterial protein synthesis but do not have significant effects on cardiac conduction. Although tetracyclines can cause other side effects like photosensitivity and gastrointestinal disturbances, QT prolongation is not a major concern.

F) Beta-lactams:
Beta-lactams, including both penicillins and cephalosporins, are not typically linked to QT prolongation. This class of antibiotics is generally considered safe with regard to cardiac effects. While beta-lactams can cause hypersensitivity reactions, gastrointestinal upset, and renal toxicity, QT prolongation is not a recognized risk associated with these drugs.