A 6-year-old boy from Connecticut presents to the emergency department with a bulls-eye-shaped rash on his upper left arm after he went hiking with his family a couple of days ago. He also has had intermittent fevers and muscle aches. The blood test for Lyme disease is positive. He has a history of hearing loss in his left ear from trauma. What side effect would prevent the physician from treating the boy with doxycycline?

Correct Answer: A

Rationale: Lyme disease (bulls-eye rash) in a 6-year-old is treated with doxycycline, but tooth discoloration in children under 8-contraindicates it. Tetracyclines bind calcium, staining developing teeth. Anemia , nephrotoxicity , and ototoxicity are rare. Myalgias (E) aren't relevant. Given his age, amoxicillin is preferred to avoid this permanent cosmetic effect, despite doxycycline's efficacy against Borrelia burgdorferi.

Correct Answer: A

Rationale: Amiodarone, labetalol, and carvedilol are not indicated for pediatric use and do not have established pediatric dosages. Phentolamine and prazosin have established pediatric dosages and would not need to be questioned. The nurse should always verify the appropriateness of medications for pediatric patients, as their pharmacokinetics and pharmacodynamics differ from adults.

Correct Answer: D

Rationale: Serotonin reuptake blockade increases synaptic levels. Buspirone, a 5-HT1A agonist, treats anxiety without reuptake effects. Pizotifen, a serotonin antagonist, prevents migraines. Granisetron, a 5-HT3 antagonist, controls nausea. Paroxetine, an SSRI, potently inhibits serotonin reuptake, elevating mood in depression. Sumatriptan activates 5-HT1 receptors. Paroxetine's mechanism is central to its antidepressant efficacy, distinguishing it from receptor modulators.

Correct Answer: C

Rationale: The fundamental action of drugs that can be used as a substitute for what is lacking in the body falls under the category of Replacement. In medical terms, replacement therapy is a type of treatment that involves replacing a hormone or other important substance that is deficient or lacking in the body. For example, individuals with hypothyroidism are often prescribed levothyroxine as a replacement therapy to make up for the thyroid hormone deficiency in their body. Similarly, insulin is used to replace the deficient insulin in individuals with diabetes. Therefore, when drugs are administered to compensate for a deficiency or lack of a specific substance in the body, they are categorized under the fundamental action of Replacement.

Correct Answer: C

Rationale: Flumazenil reverses benzo overdose (e.g., lorazepam) by blocking GABA receptors, countering sedation, per emergency protocol. Pralidoxime treats organophosphates. Naloxone and nalmefene target opioids, not benzos. Flumazenil fits, addressing overdose specifically.