Correct Answer: A

Rationale: The primary reason for administering a beta-blocker to a client with a history of myocardial infarction is to reduce myocardial oxygen demand. By reducing myocardial oxygen demand, beta-blockers help decrease the workload on the heart, making it easier for the heart to function effectively. This is crucial for clients with a history of myocardial infarction to prevent further damage to the heart. Choice B is incorrect because beta-blockers do not aim to increase cardiac output; instead, they help improve cardiac function by reducing workload. Choice C is incorrect because while beta-blockers can help prevent certain arrhythmias, the primary reason for their use in this case is to reduce myocardial oxygen demand. Choice D is incorrect as preventing angina is not the primary purpose of administering beta-blockers to a client with a history of myocardial infarction.

Correct Answer: B

Rationale: The correct answer is B: Terbinafine (Lamisil). Terbinafine is commonly used to treat onychomycosis, a fungal infection of the toenails or fingernails. It works by stopping the growth of the fungus. Micafungin (Mycamine) is an antifungal medication used for different types of fungal infections but is not typically used to treat onychomycosis. Voriconazole (Vfend) is another antifungal medication used for specific fungal infections, but it is not a first-line treatment for onychomycosis. Fluconazole (Diflucan) is also an antifungal medication, but it is more commonly used for yeast infections and may not be as effective for treating onychomycosis compared to terbinafine.

Correct Answer: B

Rationale: The correct answer is B. The effects of finasteride in treating BPH may take several weeks or months to become noticeable, so patients should be informed about this expected time frame. Choice A is incorrect because finasteride does not cure BPH but helps manage symptoms. Choice C is incorrect as increased hair growth is a side effect of finasteride, not an expected outcome for BPH treatment. Choice D is also incorrect as decreased libido is a potential side effect of finasteride, not an expected outcome for BPH treatment.

Correct Answer: C

Rationale: The correct answer is C. Viruses replicate their genetic material inside host cells, which is a fundamental aspect of their life cycle. Choice A is incorrect because viruses contain either RNA or DNA. Choice B is incorrect as viruses cannot reproduce independently and rely on host cells for replication. Choice D is incorrect as viruses are not easily killed by antimicrobials due to their unique structure and mechanisms of infection.

Correct Answer: A

Rationale: The correct answer is A: Use of nitrates. Sildenafil (Viagra) is contraindicated in patients taking nitrates due to the risk of severe hypotension. Nitrates and sildenafil both cause vasodilation, so their combined use can lead to a dangerous drop in blood pressure. Choices B, C, and D are incorrect because while a history of hypertension or use of antihypertensive medications may influence treatment decisions, they are not the key contraindication specifically related to sildenafil use.