Correct Answer: B

Rationale: The correct response is B: 'It can decrease the frequency of migraine headaches.' Feverfew is known for reducing the frequency of migraine headaches, but it has not been proven to relieve an existing migraine headache. Choices A, C, and D are incorrect because Feverfew is not used to treat skin infections, lessen nasal congestion in the common cold, or relieve nausea of morning sickness during pregnancy.

Correct Answer: B

Rationale: The correct response is B: 'It can decrease the frequency of migraine headaches.' Feverfew is known for reducing the frequency of migraine headaches, but it has not been proven to relieve an existing migraine headache. Choices A, C, and D are incorrect because Feverfew is not used to treat skin infections, lessen nasal congestion in the common cold, or relieve nausea of morning sickness during pregnancy.

Correct Answer: D

Rationale: Ketamine is known to produce psychological effects, such as hallucinations. Therefore, individuals with schizophrenia are at increased risk of experiencing exacerbation of their symptoms if given Ketamine, making it a contraindication for its use as an intravenous anesthetic. Peptic ulcer disease, breast cancer, and diabetes mellitus are not contraindications for Ketamine use as an intravenous anesthetic.

Correct Answer: A

Rationale: Tamoxifen is contraindicated in clients with a history of thromboembolic events, such as deep-vein thrombosis, due to the increased risk of blood clots. The estrogenic effects of tamoxifen can further increase the risk of thromboembolic events, making it unsafe for individuals with a history of deep-vein thrombosis. Choice B (migraine headaches), Choice C (hypertension), and Choice D (anemia) are not contraindications for tamoxifen therapy. Migraine headaches, hypertension, and anemia do not pose the same risk of adverse effects related to blood clot formation as deep-vein thrombosis does.

Correct Answer: B

Rationale: Enalapril, an ACE inhibitor, can cause hyperkalemia as an adverse effect due to decreased aldosterone levels, which leads to potassium retention. Monitoring potassium levels is essential to prevent potential complications associated with hyperkalemia. The other options, bradycardia, hypoglycemia, and hypocalcemia, are not typically associated with Enalapril use and are less likely to occur as adverse effects.