A nurse is caring for a client who is taking digoxin for heart failure and develops indications of severe digoxin toxicity. Which of the following medications should the nurse prepare to administer?

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.

D) Trough:
The trough level of a medication is the lowest concentration of the drug in the bloodstream before the next dose is administered. Monitoring the trough level helps ensure that the medication stays within a therapeutic range, minimizing the risk of toxicity and ensuring effectiveness.

A) Half-life:
Half-life refers to the time it takes for the concentration of a drug in the blood to decrease by half. It is related to how long the drug stays in the system but does not specifically indicate the lowest concentration.

B) Peak:
The peak level is the highest concentration of the drug in the bloodstream after administration. It is used to assess the maximum effect of the drug, not the lowest concentration.

C) Toxic:
Toxic level refers to the concentration of a drug at which it can cause adverse effects or toxicity. It is not related to the lowest concentration but rather to potentially harmful levels.