Correct Answer: C

Rationale: The correct answer is C. Sildenafil (Viagra) enhances the vasodilating effect of nitric oxide and is contraindicated with the concurrent use of organic nitrates and nitroglycerin. Using nitroglycerin together with Viagra can lead to severe hypotension and cardiovascular collapse, making it unsafe to combine both medications.

Correct Answer: D

Rationale: The correct instruction for administering mycophenolate mofetil (CellCept) is to contact the healthcare provider (HCP) if unusual bleeding or bruising, sore throat, or other adverse effects occur. It is essential not to open or crush the capsules to maintain the medication's efficacy.

Correct Answer: B

Rationale: The correct answer is to increase fluid intake to 2000 to 3000 mL daily. Cyclophosphamide can cause hemorrhagic cystitis as a toxic effect. By increasing fluid intake, the client can help prevent this complication by promoting frequent urination, which reduces the concentration of the drug and its metabolites in the bladder. This dilution effect can help reduce the risk of bladder toxicity.

Correct Answer: D

Rationale: The primary action of tamoxifen, an antineoplastic medication used in metastatic breast carcinoma, is to compete with estradiol for binding to estrogen receptors in tissues with high receptor concentrations. By doing so, tamoxifen reduces DNA synthesis and estrogen response, leading to its therapeutic effect in inhibiting the growth of estrogen-sensitive breast cancer cells.

Correct Answer: B

Rationale: Before administering amlodipine, it is important to check the client's blood pressure and heart rate. Amlodipine is known to lower blood pressure and heart rate as part of its mechanism of action. Monitoring these vital signs helps ensure the safety of the client and allows for appropriate assessment of the medication's effects post-administration.