The pregnant patient tells the nurse that her prescribed medication is not as effective as it was before her pregnancy. What is the best response by the nurse?

Correct Answer: A

Rationale: Pregnancy increases blood volume (50% more), diluting drugs, reducing efficacy-e.g., lower concentration per unit volume, a pharmacokinetic shift. Asking about administration checks adherence, not cause. Baby receiving drug is unlikely-placental transfer varies. Expiration is a guess, not tied to pregnancy. Blood volume explains the change, addressing her concern.

Correct Answer: C

Rationale: Seasonal affective disorder (SAD) ties depression to winter-less light, per psychiatry-unlike baby blues (postpartum), bipolar (cycles), or OCD (obsessions). SAD's seasonal link defines it, matching symptoms.

Correct Answer: A

Rationale: The percentage of ionization of a weak acid or base can be estimated using the Henderson-Hasselbalch equation:

Correct Answer: D

Rationale: Overdose toxicities differ in acid-base effects. Methanol causes metabolic acidosis via formic acid, not respiratory alkalosis. Lead poisoning leads to anemia or neurologic issues, rarely acid-base shifts. Paracetamol overdose induces lactic acidosis from liver failure, not respiratory changes initially. Salicylate (e.g., aspirin) overdose stimulates the respiratory center early, causing hyperventilation and respiratory alkalosis (low pCO2), but severe cases add metabolic acidosis (high anion gap) from uncoupled oxidative phosphorylation and lactic acid buildup. Codeine, an opioid, depresses respiration, causing acidosis, not alkalosis. Salicylate's dual pattern is distinctive, requiring urgent recognition—initial alkalosis shifts to acidosis as toxicity worsens, guiding bicarbonate or dialysis treatment.

Correct Answer: A

Rationale: ACE inhibitors, such as enalapril and lisinopril, work by blocking the enzyme angiotensin-converting enzyme (ACE), which is responsible for converting angiotensin I into angiotensin II. By inhibiting this conversion, ACE inhibitors prevent the vasoconstrictor and aldosterone-stimulating effects of angiotensin II at the receptor sites. This leads to vasodilation, decreased blood pressure, and reduced aldosterone secretion. This mechanism of action makes ACE inhibitors an important class of medications for managing conditions such as hypertension, heart failure, and chronic kidney disease.