Who is the primary authority source for drug standards in the United States?

A) 0.2 mg
The correct way to write the dosage is 0.2 mg. In pharmacology and medication administration, it is important to follow the guidelines set by the Institute for Safe Medication Practices (ISMP) and other standard bodies, which recommend that a leading zero be used before a decimal point. This helps to prevent errors in interpreting the dosage. Writing 0.2 mg clearly indicates two-tenths of a milligram, and the leading zero makes it easier to avoid misreading the dose as a whole number (2.0 mg) or omitting the decimal point entirely.

B) .2 mg
Writing the dosage as .2 mg (without the leading zero) is considered unsafe and is a poor practice. The absence of the leading zero before the decimal point increases the likelihood that the dose may be misread. For example, someone could confuse .2 mg with 2.0 mg or misinterpret it in a hurried situation, which could lead to a tenfold dosing error

C) 2.0 mg
Writing 2.0 mg would indicate two milligrams, which is not the correct dosage for "two-tenths of a milligram." While this format does use a decimal point, it does not represent the correct dose. This error could lead to an overdose if misread as a whole number.

D) 0.20 mg
While 0.20 mg is technically correct, it is not the preferred or necessary format. The use of two decimal places is unnecessary in this case. Since the dosage is two-tenths of a milligram, 0.2 mg is simpler and clearer. Using an unnecessary trailing zero (the second "0") can cause confusion or misinterpretation, especially in critical settings where every detail counts.

A) Neutropenia
Neutropenia refers to an abnormally low level of neutrophils, a type of white blood cell. While certain medications, such as chemotherapy agents and some antipsychotic drugs, can cause neutropenia, atenolol (a beta-blocker) is not typically associated with this side effect. Atenolol primarily affects the cardiovascular system by reducing heart rate and blood pressure, and it is not known to cause significant changes in white blood cell counts.

B) Bradycardia
Bradycardia, or a slower-than-normal heart rate, is a well-known and common adverse effect of beta-blockers, including atenolol. Beta-blockers work by blocking beta-adrenergic receptors, which decreases the heart rate and the force of contraction, as well as lowering blood pressure. In some individuals, this can lead to excessively low heart rates, which could be dangerous if the heart rate drops too much. Bradycardia can lead to symptoms such as dizziness, fainting, or fatigue, and may require dose adjustments or discontinuation of the medication

C) Anemia
Anemia, which is a condition characterized by a low red blood cell count or low hemoglobin levels, is generally not a common adverse effect of atenolol. While certain medications like some chemotherapeutic agents, NSAIDs, or antibiotics may cause anemia due to their effects on the bone marrow or by causing gastrointestinal bleeding, atenolol is not typically linked to this side effect.

D) Hypokalemia
Hypokalemia (low potassium levels) is typically associated with the use of diuretics or other medications that cause the kidneys to excrete more potassium, such as some classes of antibiotics and corticosteroids. However, atenolol, being a beta-blocker, does not directly affect potassium levels.