If a drug is not metabolized, is bound 50% to plasma protein, and has a renal clearance of 400 mL/min in man, the mode of excretion must be:

Question

Quizplus · Accepted Answer

The renal clearance of 400 mL/min is higher than the normal glomerular filtration rate (GFR) of about 125 mL/min, indicating that the drug is not only filtered but also secreted. Since the drug is 50% bound to plasma proteins, only the unbound fraction is filtered, further supporting the involvement of tubular secretion in its excretion.

If a Drug Is Not Metabolized, Is Bound 50% to Plasma