Correct Answer: A

Rationale: The correct answer is A. The nurse should instruct clients to take iron on an empty stomach, 1 hour before meals to maximize absorption. This enhances the medication's effectiveness. Option B is incorrect because dark green stool is a common side effect of iron supplements and does not necessarily indicate a problem. Option C is incorrect as dietary fiber intake does not need to be decreased while taking iron supplements. Option D is incorrect because antacids can interfere with the absorption of iron and should not be taken at the same time.

Correct Answer: A

Rationale: The correct answer is to advise the client to take montelukast once daily at bedtime to maintain therapeutic effects. Choice B is incorrect because montelukast is not typically used for acute asthma management but for chronic treatment. Choice C is incorrect as there are no known interactions between montelukast and dairy products. Choice D is incorrect as it is not safe to double up on doses if the client forgets to take the medication; the missed dose should be skipped and the regular dosing schedule maintained.

Correct Answer: B

Rationale: Renal failure is a contraindication to opioid therapy due to the risk of drug accumulation and toxicity. Asthma, diabetes mellitus, and obesity are not contraindications to opioid therapy. Asthma is a respiratory condition that can be managed alongside opioids, diabetes mellitus and obesity do not directly contraindicate opioid therapy.

Correct Answer: A

Rationale: The correct answer is A: Hepatotoxicity. Disulfiram is known to cause hepatotoxicity as a severe adverse effect. This occurs due to the inhibition of aldehyde dehydrogenase, leading to the accumulation of acetaldehyde when alcohol is consumed. Wernicke's aphasia (Choice B) is a language disorder unrelated to disulfiram therapy. Suicidal ideations (Choice C) may be associated with certain medications, but it is not a common adverse effect of disulfiram. Diarrhea (Choice D) is not a typical adverse effect of disulfiram.

Correct Answer: B

Rationale: The correct instruction for administering insulin is to rotate injection sites to prevent lipodystrophy, a common complication of insulin therapy. Injecting into the deltoid muscle (Choice A) is not recommended for insulin injections. Massaging the site after injection (Choice C) is not necessary and can potentially increase the risk of lipodystrophy. Using the same site for each injection (Choice D) can lead to localized tissue damage and absorption irregularities, making it an incorrect choice.