Figure 3: Terminal concentration profiles in selected physiological compartments for dosage regimens that are known to cause birth defects. In this case, lithium medication is administered twice daily and controlled-release tablets release lithium over 4 hours. A pulse function corresponding to the drug absorption is shown above each figure. (a) One dose of a 450 mg tablet (12 mEq lithium) with a subsequent 900 mg (24 mEq lithium) dose. (b) Two doses of a 900 mg tablet (24 mEq lithium).