Superficial bladder cancer can be treated by direct instillation of the antineoplastic antibiotic agent mitomycin (Mutamycin). This process is termed:

Correct Answer: B

Rationale: Intravesical administration involves the direct instillation of medication into the bladder, which is a common method for treating superficial bladder cancer. This approach allows high concentrations of the drug, such as mitomycin, to come into direct contact with the cancerous cells lining the bladder, minimizing systemic side effects. Intraventricular and intrathecal administrations are used for delivering drugs to the brain and spinal cord, respectively, while intravascular administration refers to intravenous delivery. Intravesical administration is specifically designed for bladder conditions, making it the correct answer.

Correct Answer: B

Rationale: Converting atrial fibrillation (AF) to sinus rhythm requires cardioversion or antiarrhythmics. Digoxin controls rate, not rhythm, ineffective for conversion. Atenolol, a beta-blocker, and diltiazem, a calcium channel blocker, manage rate, not rhythm restoration. Lidocaine treats ventricular arrhythmias. Amiodarone, a class III antiarrhythmic, prolongs repolarization, effectively converting AF to sinus rhythm, especially in acute settings, outperforming others. Its broad-spectrum action is key in AF management, balancing efficacy and safety.

Correct Answer: C

Rationale: Nitrous oxide has a high minimum alveolar concentration (MAC >100%), not low, due to low potency, so that's false. Halogenated agents (e.g., isoflurane) have higher brain:blood coefficients, reflecting solubility, making that false. They reduce mean arterial pressure (MAP) proportional to alveolar concentration via vasodilation, a true statement. Nitrous oxide does decrease tidal volume and increase respiratory rate, true. They don't reduce cerebral metabolic rate via blood flow alone but directly. MAP reduction is a key hemodynamic effect, guiding anesthetic depth monitoring.

Correct Answer: A

Rationale: Terazosin, an alpha-1 blocker, treats hypertension and benign prostatic hyperplasia (BPH) by relaxing vascular and prostate smooth muscle, lowering blood pressure and easing urinary flow. Sildenafil, for erectile dysfunction, doesn't address hypertension or BPH and may drop blood pressure, risking complications. Finasteride shrinks the prostate for BPH but doesn't affect hypertension, missing the dual need. Tamsulosin, also for BPH, can cause hypotension but isn't used routinely for hypertension management. Terazosin's dual efficacy makes it safe and suitable, addressing both conditions without worsening either, unlike alternatives lacking hypertensive benefits or posing risks.

Correct Answer: D

Rationale: Mean effective dose (ED50) affects 50% of a population, but individuals vary-some need more or less due to metabolism, weight, or genetics, a clinical reality. Severe side effects aren't 50%-that's toxicity. Ethnic differences influence response, but dose variation is broader. No effect in 50% misreads ED50. Dose adjustment reflects individual pharmacokinetics, key to practice.