A 29-year-old woman presents to her primary care physician for a regular yearly checkup. She has a history of a seizure disorder and has been taking an antiseizure medication for 8 years. She is also taking an oral contraceptive. She is in good health but complains that her gums seem to be overgrowing her teeth. Which of the following medications is likely responsible for her chief complaint?

Correct Answer: C

Rationale: Gingival hyperplasia is a side effect of Phenytoin , an antiseizure drug. Estrogen and Progesterone in contraceptives don't cause this. Lamotrigine and Valproic acid (E) lack this effect. Phenytoin's long-term use induces gum overgrowth, fitting her 8-year history.

Correct Answer: B

Rationale: High-dose androgens in females are used palliatively for certain breast cancers, especially hormone-sensitive ones, to suppress estrogen-driven tumor growth, easing symptoms in advanced disease. Athletic performance enhancement via androgens, while feasible, isn't clinically indicated and is illegal in regulated contexts. Brain cancer lacks evidence for androgen treatment, as it doesn't target neurological tumors. Sexual reassignment uses testosterone for masculinization, but high doses in clinical settings typically tie to cancer care, not transition. Breast cancer aligns with a recognized therapeutic use, leveraging androgens' anti-estrogenic effects, making it the most valid clinical rationale here.

Correct Answer: B

Rationale: Ondansetron is a medication commonly used to prevent and treat nausea and vomiting, particularly in patients undergoing chemotherapy or surgery. It belongs to a class of drugs known as antiemetics, which work by blocking serotonin, a neurotransmitter that can trigger nausea and vomiting. By inhibiting the effects of serotonin, ondansetron helps to reduce the incidence and severity of these symptoms, providing a therapeutic effect for individuals experiencing nausea and vomiting.

Correct Answer: D

Rationale: Phenytoin and carbamazepine are antiepileptic drugs with a shared mechanism: they stabilize neuronal membranes by preventing sodium influx through fast sodium channels, reducing excitability and controlling seizures, particularly in partial and tonic-clonic types. Both induce hepatic cytochrome P450 enzymes, accelerating metabolism of other drugs, not inhibiting it. Phenytoin exhibits zero-order elimination at high doses due to enzyme saturation, while carbamazepine follows first-order kinetics, so this isn't a shared trait. They reduce the efficacy of oral contraceptives by inducing their metabolism, not enhancing them. Safety in pregnancy is questionable, with both linked to teratogenicity (e.g., fetal hydantoin syndrome). The sodium channel blockade is the fundamental property uniting their therapeutic effects, making it the key characteristic they share, critical to their role in epilepsy management.

Correct Answer: B

Rationale: HMG-CoA reductase inhibitors, also known as statins, are a class of antilipemic drugs commonly prescribed to lower cholesterol levels. One side effect associated with statin use is myopathy, which manifests as muscle pain, tenderness, or weakness. In severe cases, myopathy can progress to rhabdomyolysis, a condition characterized by muscle breakdown and release of muscle fiber contents into the blood, potentially leading to kidney damage. It is essential for healthcare providers, such as nurses, to monitor patients on statin therapy for signs and symptoms of myopathy to intervene promptly if necessary. Niacin, fibric acid derivatives, and bile acid sequestrants are not typically associated with myopathy as a common side effect.