Correct Answer: B

Rationale: The therapeutic serum level for digoxin ranges from 0.5 to 2 ng/mL. This range is considered optimal for therapeutic effects while minimizing the risk of toxicity. Levels above 2 ng/mL may lead to digoxin toxicity, which can manifest as anorexia among other symptoms. Therefore, the nurse should be vigilant in monitoring the digoxin levels to ensure the client's safety and therapeutic effectiveness of the medication.

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: C

Rationale: Rifampin causes orange-red discoloration of body secretions, including sweat, tears, urine, and feces. It can also permanently stain soft contact lenses. It is essential to take rifampin exactly as directed and not discontinue it without consulting the healthcare provider.

Correct Answer: B

Rationale: Tiotropium (Spiriva) is not a rescue inhaler but a maintenance medication for COPD. The correct instruction for the nurse to include in the teaching plan is to advise the client to rinse their mouth after using the inhaler. This practice helps prevent dry mouth and throat irritation, common side effects of tiotropium. There are no specific recommendations to take tiotropium on an empty stomach or with a full glass of water.

Correct Answer: A

Rationale: When ciprofloxacin (Cipro) is given with warfarin sodium (Coumadin), it can potentiate the effects of warfarin, leading to an increased risk of bleeding. Therefore, the nurse should closely monitor the client's INR levels and watch for signs of bleeding such as bruising, petechiae, or black tarry stools.