Some drugs are excreted into bile and delivered to the intestines. Prior to elimination from the body, the drug may be absorbed. This process is known as:

Correct Answer: C

Rationale: Enterohepatic cycling refers to the process where drugs excreted into bile are delivered to the intestines and then reabsorbed into the bloodstream. This recycling can prolong the drug's presence in the body and its therapeutic effects. Hepatic clearance and total clearance refer to the liver's ability to remove drugs from the bloodstream, while the first-pass effect involves the metabolism of drugs before they reach systemic circulation. Enterohepatic cycling is a unique mechanism that impacts drug pharmacokinetics.

Correct Answer: B

Rationale: Systemic corticosteroids (e.g., prednisone) for ulcerative colitis cause side effects. Osteoporosis results from reduced bone formation over time. Diabetes stems from glucocorticoid-induced hyperglycemia. Hypertension occurs via sodium retention and vasoconstriction. Mood changes are common due to CNS effects. Weight loss isn't typical; corticosteroids cause weight gain from increased appetite and fat redistribution, making it the exception. This reflects their metabolic impact, requiring monitoring in chronic use.

Correct Answer: C

Rationale: Neonates have an immature blood-brain barrier, increasing opioid penetration, not blocking it, so that's false. Spinal analgesia involves mu, delta, and kappa receptors, not just one type, making that false. Depressed CO2 response is the most reliable sign of opioid-induced respiratory depression, a true statement, reflecting medullary suppression. Tolerance to miosis develops minimally, unlike analgesia, so that's false. Addison's patients are hypersensitive to opioids due to cortisol lack. The CO2 response is a key monitoring parameter in opioid overdose.

Correct Answer: B

Rationale: Finasteride (Proscar), a 5-alpha reductase inhibitor, shrinks the prostate in BPH by reducing dihydrotestosterone, easing urinary obstruction. Smooth muscle relaxation is for ED drugs like sildenafil. It lowers DHT, not testosterone, and doesn't stimulate RNA synthesis. Prostate shrinkage is its core action, distinct from other mechanisms.

Correct Answer: D

Rationale: The Human Genome Project enables pharmacogenomics, tailoring drugs to genetic profiles for better efficacy (e.g., CYP2D6 variants), not eliminating drugs. Standardized doses ignore genetics. Disease prevention via genes complements, not replaces, drugs. Individualized therapy leverages genomics, enhancing treatment precision.