Medications bound to protein have the following effect:

Correct Answer: C

Rationale: When medications are bound to proteins in the bloodstream, they are inactive and unable to exert their therapeutic effects. Only the unbound (free) fraction of the drug is pharmacologically active. Therefore, the more a drug is bound to protein, the less available it is for its desired effect. Protein binding also affects the drug's distribution and metabolism, but it does not enhance availability or increase liver metabolism. Rapid distribution to receptor sites is influenced by other factors, such as blood flow and tissue permeability.

Correct Answer: C

Rationale: Chronic hepatitis C (HCV) treatment targets viral clearance. Pegylated interferon alfa boosts immunity, lamivudine treats HBV, not HCV, so that's incorrect. Adefovir also targets HBV, not HCV. Pegylated interferon alfa with ribavirin, an antiviral, is a historical standard for HCV, enhancing sustained virologic response across genotypes, the recommended combo. Adefovir/lamivudine suits HBV, oseltamivir/zanamivir influenza. Ribavirin's synergy with interferon was key before direct-acting antivirals, effective for this condition.

Correct Answer: A

Rationale: Pancuronium is primarily renally eliminated, a true statement, prolonged in kidney failure. Rocuronium, a steroidal agent, not isoquinolone (like atracurium), is false. Rocuronium is hepatically metabolized, not via Hofmann elimination (atracurium does), so that's false. Vecuronium is mostly biliary excreted, not renal, making that false. Atracurium uses plasma esterases and Hofmann elimination, not pseudocholinesterases alone. Pancuronium's renal clearance is critical for surgical planning, especially in renal patients.

Correct Answer: D

Rationale: Sildenafil (Viagra), a phosphodiesterase-5 inhibitor, treats erectile dysfunction (ED) by enhancing penile blood flow, a first-line therapy. Leuprolide suppresses testosterone for prostate cancer, worsening ED. Finasteride and tamsulosin, for BPH, don't target ED and may cause it. Sildenafil's vascular action offers rapid efficacy, making it the go-to choice.

Correct Answer: B

Rationale: Individual variation-metabolism, weight, genetics-dictates dose differences, a pharmacokinetic truth explaining her higher amount. Female metabolism isn't universally higher. Hormones affect response, but not broadly dose. Body fat impacts distribution, not directly dose here. Uniqueness covers all factors, reassuring and accurate.