Question

Which of the following drug can get distributed in the excess body space?

(a) Phenytoin

(b) Caffeine

(c) Digoxin

(d) Antibiotics

I got this question by my school principal while I was bunking the class.

Question is taken from Pharmacokinetic Principles Applications in division Applications of Pharmacokinetic Principles, Diuretics, Drug Concentration and Pharmacologic Response of Drug Biotechnology

Answer 1

Correct choice is (c) Digoxin

The explanation: For drugs such as digoxin which do not distribute in the excess body space, the volume of distribution do not change and hence dose for administration to a patient should calculated on the basis of ideal body weight. For polar drugs for e.g. antibiotics which distribute in excess body space of obese patients to an extent less than that in lean tissues. Drugs such as caffeine, theophylline, lidocaine and lorazepam gets distributed in same extent in both lean and adipose tissues.