Combination chemotherapy is used in the treatment of cancer because:

Correct Answer: A

Rationale: Combination chemotherapy is used to target cancer cells through multiple mechanisms, reducing the likelihood of resistance. Single-agent therapy often leads to the development of resistant cell lines, as cancer cells can adapt to the drug. By using a combination of drugs with different mechanisms of action, the treatment can more effectively kill cancer cells and prevent resistance. While two drugs may increase efficacy, the primary rationale is to overcome resistance. Larger doses of single agents are not the main reason for combination therapy.

Correct Answer: B

Rationale: The beta-adrenergic blocking agents are used to treat cardiovascular problems (hypertension, angina, migraine headaches) and to prevent reinfarction after MI. The prototype drug, propranolol, was in fact the most prescribed drug in the country in the 1980s and is still considered a first-line drug. Propranolol does not prevent first MIs and it is not used for hypotension or cluster headaches. The nurse should understand the indications for propranolol to ensure safe and effective administration.

Correct Answer: C

Rationale: Redness and pain at the site of the infusion are important signs of a potential infiltration or extravasation of the medication, in this case pentamidine (Pentam) IV. Pentamidine is an antimicrobial medication used to treat and prevent Pneumocystis jiroveci pneumonia (PCP) in patients who are immunocompromised, such as those with HIV. Infiltration or extravasation of IV medications can lead to significant tissue damage, necrosis, and other complications. Therefore, it is crucial to immediately address any signs of redness and pain at the infusion site to prevent further harm to the patient. This assessment finding should be promptly relayed to the physician for appropriate management, which may include discontinuation of the infusion, monitoring for complications, and providing alternative treatments if necessary. The other assessment findings (blood pressure of 100/62 mm/Hg

Correct Answer: A

Rationale: Methanol, a toxic alcohol, is metabolized by alcohol dehydrogenase into formaldehyde, then by aldehyde dehydrogenase into formic acid, causing severe metabolic acidosis and blindness via optic nerve damage. This initial step—formation of formaldehyde—is the critical toxic event, distinguishing methanol poisoning from ethanol's safer metabolism. Nephrotoxicity isn't primary; formic acid affects mitochondria and eyes more. Hypotension and vomiting occur secondary to acidosis but aren't the defining process. Glycolic acid is a metabolite of ethylene glycol, not methanol. Methanol inhibits aldehyde dehydrogenase minimally; its danger lies in metabolite accumulation. Formaldehyde production initiates the cascade, making it the most direct and accurate consequence of methanol ingestion.

Correct Answer: C

Rationale: The therapeutic range for Lithium is typically considered to be 0.6-1.2 mEq/L for maintenance treatment. However, some sources may also suggest a wider therapeutic range of 0.5-2 mEq/L. Monitoring serum lithium levels is crucial to ensure that the patient is within the therapeutic range and to adjust the dosage accordingly to avoid toxicity or subtherapeutic levels. Thus, option C (0.5-2) provides a more comprehensive and inclusive range that is commonly referenced in clinical practice.