Part 1 of this two-part series in clinical pharmacokinetics (J Natl Med Assoc 1985; 77:475-482) introduced the clinician to the basic principles required for rational therapeutic drug management at the bedside. Practical problems were included that demonstrated how these principles could be put to clinical use.In Part 2 the clinical pharmacology of three commonly used drugs (theophylline, digoxin and gentamicin) are discussed, and practical problems are presented to illustrate the use of their pharmacokinetic profiles.