A 27-year-old medical student has recurrent sinusitis and takes an over-the-counter agent. Unfortunately, he fell asleep while taking his final examination of the anatomy course. Which of the following agents is most likely to cause this adverse effect?

Correct Answer: D

Rationale: Sinusitis treatment often involves OTC antihistamines. Diphenhydramine , an H1 antihistamine, causes sedation, explaining the student's sleepiness during the exam. Doxycycline , an antibiotic, doesn't sedate. Doxylamine , another sedating antihistamine, is possible but less commonly linked to sinusitis OTC use. Doxazosin , an α-blocker, isn't for sinusitis. Hydroxyzine (E) sedates but is prescription-based. Diphenhydramine's widespread OTC availability and drowsiness side effect fit the scenario, impacting the student's performance.

Correct Answer: C

Rationale: In Fried's rule for dosage calculation, the formula is to divide the child's age in months by 150 to find the fraction of adult dose that can be tolerated. Generally, a child is considered to tolerate an adult dose when they have reached 12 months of age. This is based on the assumption that a 12-month-old child can typically tolerate a dose similar to that of an adult. Therefore, the correct answer is 12 months, which is option C.

Correct Answer: C

Rationale: Penicillin is classified as an antibiotic drug, specifically an antibacterial agent. It is used to treat various bacterial infections by inhibiting the growth of bacteria or killing them directly. Therefore, it is not categorized as an antiarrhythmic, anticonvulsant, or mood stabilizer. Instead, Penicillin falls under the classification of drugs that are effective against bacterial infections, making it an "anti-ineffective" drug.

Correct Answer: A

Rationale: Rash 3 months after stopping allopurinol suggests contact dermatitis . Allopurinol's hypersensitivity resolves faster. Dermatitis herpetiformis , carcinoma , and telangiectasia (E) don't fit. An external allergen likely caused this delayed presentation.

Correct Answer: B

Rationale: Omeprazole, a proton pump inhibitor (PPI), is most effective when taken 30 minutes before meals. This allows the medication to inhibit proton pumps during meal-stimulated acid production. Taking it after (A) or with meals (C) reduces its effectiveness. While it can be taken without regard to meals (D), taking it before meals is optimal.