One hour after receiving intravenous morphine sulfate, a patient reports generalized itching. The nurse assesses the patient and notes clear breath sounds, no rash, respirations of 14 breaths per minute, a heart rate of 68 beats per minute, and a blood pressure of 110/70 mm Hg. Which action will the nurse take?

Correct Answer: D

Rationale: The nurse should prepare an epinephrine injection in case of an anaphylactic reaction. While generalized itching is a common side effect of morphine, the presence of itching along with clear breath sounds and absence of rash may suggest a possible allergic reaction. Anaphylactic reactions can be life-threatening and may present with symptoms such as itching, respiratory distress, and cardiovascular collapse. Therefore, having epinephrine readily available is crucial in case an anaphylactic reaction occurs, as it is the treatment of choice for such a reaction.

Correct Answer: D

Rationale: Infants have a higher percentage of total body water (approximately 75%) compared to adults. This difference affects the distribution and concentration of water-soluble drugs, often requiring adjustments in dosing to achieve therapeutic effects. Increased protein in circulation, lower fat composition, and more muscular body composition are not primary factors influencing drug therapy in infants. Therefore, the nurse must consider the higher water composition when calculating drug dosages for pediatric patients.

Correct Answer: A

Rationale: Bioavailability is defined as the fraction of drug that reaches systemic circulation in an unchanged form after administration. It is a crucial pharmacokinetic parameter that reflects the amount and rate of drug absorption. Bioavailability can be influenced by various factors such as the route of administration, drug formulation, and first-pass metabolism. Monitoring bioavailability is important in determining the efficacy and dosage requirements of a drug.

Correct Answer: A

Rationale: Levodopa is a prodrug converted to dopamine in the brain, bypassing the blood-brain barrier. Prodrugs are inactive compounds metabolized into active drugs in the body.

Correct Answer: D

Rationale: Absence seizures, brief lapses in consciousness, require specific antiepileptics. Carbamazepine, effective for focal seizures, can worsen absence seizures by enhancing sodium channel activity. Topiramate and clobazam have broader uses but limited efficacy here. Phenytoin suits tonic-clonic, not absence. Ethosuximide reduces T-type calcium currents in thalamic neurons, directly targeting absence seizure mechanisms, making it most effective. Its specificity ensures rapid control, critical for pediatric epilepsy management.