MCQ Pharmacology Answer 16

Active secretion can result in the clearance of about 650 ml of plasma per minute.Total body water is about 60 % of body weight, or (0.6)(70 kg) = 42,000 ml. If T1/2 = half time, Cl = clearance, and VD = volume of distribution, then since T1/2 = (0.693)(VD)/Cl T1/2 = (0.693)(42,000)/650 or ~ 45 minutes.

A Drugs stored in body depots such as fat or muscle have a high volume of distribution (VD). This results in a long half-life [T1/2 = (o.693)(VD)/Cl where Cl = clearance.]

D Reversible plasma protein binding does not reduce the rate of secretion because as some drug is transported more is almost instantly released frm its binding site. Reversible plasma protein binding does not reduce the rate of secretion because as some drug is transported more is almost instantly released frm its binding site. Reversible plasma protein binding does not reduce the rate of secretion because as some drug is transported more is almost instantly released frm its binding site.

E Glomerular filtration can clear a maximum of about 30 ml/minute. If T1/2 = half-time, Cl = clearance, and VD = volume of distribution, then since T1/2 = (0.693)(VD)/Cl, the shortest half lif would be: T1/2 = (0.693)(42,000)/130 = about 225 minutes.

Category: Pharmacology MCQs