A nurse is teaching a class about pharmacodynamics. The nurse should include that which of the following medication levels occurs when a medication is at the lowest serum concentration?

A) Withholding the medication if the heart rate is above 100/min:
Digoxin is typically withheld if the heart rate is below 60 beats per minute (bradycardia) rather than above 100 beats per minute. In fact, a heart rate above 100/min may indicate tachycardia, which is not necessarily a contraindication for administering digoxin.

B) Evaluating the client for nausea, vomiting, and anorexia:
These symptoms are signs of digoxin toxicity. Evaluating for these symptoms is crucial as part of monitoring for adverse effects. Clients experiencing these symptoms may need their digoxin levels checked and potentially adjusted.

C) Instructing the client to eat foods that are low in potassium:
Digoxin therapy requires adequate potassium levels for effectiveness. Clients should be encouraged to consume foods high in potassium to prevent hypokalemia, which can increase the risk of digoxin toxicity.

D) Measuring apical pulse rate for 30 seconds before administration:
The apical pulse should be measured for a full minute to accurately assess the heart rate before administering digoxin. A shorter measurement may not provide a reliable assessment of the heart rate.

A) Ask the client to remain in a side-lying position with the affected ear down for several minutes after instillation:
While this position helps ensure the medication remains in the ear canal, it is not as critical as ensuring the medication is at the correct temperature to avoid discomfort. The client should be informed to remain in this position if recommended by the medication instructions.

B) Pull the client's pinna down and back prior to instillation:
Pulling the pinna down and back is appropriate for children under 3 years of age. For clients over 3 years, the pinna should be pulled up and back to straighten the ear canal for effective delivery of the medication.

C) Press a cotton ball into the client's ear canal after instillation:
Pressing a cotton ball into the ear canal is not generally recommended as it can cause discomfort and potentially prevent the medication from being absorbed properly. It's better to leave the ear open after instillation unless otherwise directed by specific instructions.

D) Warm the medication to room temperature before administration:
Warming the medication to room temperature is an important step because it helps prevent discomfort or dizziness that can occur if the medication is too cold. This action enhances patient comfort and ensures effective administration of the medication.