The nurse is reviewing factors that influence pharmacokinetics in the neonatal patient. Which factor puts the neonatal patient at risk with regard to drug therapy?

Correct Answer: A

Rationale: Neonates have an immature renal system, which affects the excretion of drugs and their metabolites. This immaturity can lead to prolonged drug half-lives and an increased risk of toxicity. While hyperperistalsis, irregular temperature regulation, and smaller circulatory capacity can influence drug therapy, the immature renal system is the most significant factor. Nurses must consider this when administering medications to neonates and adjust dosages accordingly to ensure safety and efficacy.

Correct Answer: D

Rationale: Antiepileptics vary in side effects. Valproate causes tremor or hepatotoxicity, not visual defects. Carbamazepine risks rash or hyponatremia, not eyes. Lamotrigine is linked to rash, tiagabine to dizziness, without visual impact. Vigabatrin, a GABA-transaminase inhibitor, causes irreversible concentric visual field defects in ~30-40% of users due to retinal toxicity, a unique and serious adverse effect. This necessitates ophthalmologic monitoring, distinguishing it in epilepsy treatment choices.

Correct Answer: A

Rationale: Most beta-blockers (e.g., propranolol, metoprolol) have half-lives of 3-10 hours, a true statement reflecting their typical duration, useful for dosing frequency. They have a large, not small, volume of distribution due to tissue penetration, so that's false. Many have good oral bioavailability, not poor, especially non-selective ones. Lipid solubility varies (e.g., propranolol is high, atenolol low), but many cross the BBB, causing CNS effects, though not universally true. They're often metabolized, not excreted unchanged. The half-life range is a key pharmacokinetic feature, guiding their use in hypertension or angina.

Correct Answer: A

Rationale: Testosterone patches require placement on hair-free skin to ensure proper adhesion and absorption, as hair can block drug delivery, reducing efficacy. Active areas like the thigh or arm are suitable if hairless and dry, contrary to avoidance claims-rotation across such sites is standard. Patches are changed daily, not weekly, for consistent hormone levels. Rash observation is key due to potential skin irritation, a common side effect. Hair-free placement is critical education, directly impacting bioavailability, unlike timing or site activity, which follow secondary guidelines, ensuring effective therapy for hypogonadism or related conditions.

Correct Answer: C

Rationale: Pharmacokinetics comprises absorption (entry to blood), distribution (to tissues), metabolism (chemical change), and excretion (removal)-standard categories tracking a drug's journey. Others mix processes or invent terms (e.g., interspersing), lacking precision. These four define the field, essential for dosing and effect.