Pharmacokinetics. What are Cmax and Cmin?

The following pharmacological definition has been taken from the Pharmacology and Experimental Therapeutics Department Glossary at Boston University School of Medicine.

Cmax, Cmin:

The maximum or “peak” concentration (Cmax) of a drug observed after its administration; the minimum or “trough” concentration (Cmin) of a drug observed after its administration and just prior to the administration of a subsequent dose. For drugs eliminated by first-order kinetics from a single-compartment system, Cmax, after n equal doses given at equal intervals is given by C0(1 – fn )/(1 – f) = Cmax, and Cmin = Cmax – C0.

The time following drug administration at which the peak concentration of Cmax occurs, tp (for any route of administration but the intravenous), is given by tp = (ln ka – ln kel )/(ka – kel). (Remember that ln is the natural logarithm, to the base e, rather than the common logarithm or logarithm to the base 10; ln X=2.303 log X.)

The copyright of the text is held by Trustees of Boston University. Permission has been granted for its use in this blog.

Illustrated Psychopharmacology Lectures in Your Inbox

  • Mechanisms of action, adverse effects and indications of psychotropic medications.
  • Concise and illustrated presentations. 
  • Practical tips for mental health professionals.

laptop2


 

 

Are you a visual learner interested in learning psychopharmacology? Click here to get our videos