To the editor: Lithium carbonate is now marketed in 300-mg dosage forms by five different manufacturers. A liquid form of lithium, as the citrate salt, was also introduced in 1978, with each teaspoonful providing the lithium equivalent of a 300-mg tablet or capsule. Although the individual manufacturers have provided data showing bioequivalence of their marketed lithium dosage forms (1, 2), little has been published investigating comparative bioavailability of different brands.
At this institution, two cases have concerned us in this regard. In one case, a manic-depressive patient who had received 300 mg of a popular brand (Eskalith®) four times daily