Lithium every second day: Is the prophylactic effect preserved?

Abstract

1. 1. Ten patients (3 male, 7 female) 23–61 years of age were enrolled in this 2-year multi-national W.H.O. collaborative study. All patients were diagnosed as having an Affective Disorder according to DSM-III. They were clinically stabilized on Lithium Carbonate ranging from 600mg to 1200mg on a once daily basis for at least 6 months prior to the study. Evaluations consisted of an 8-item Side effect Checklist, HAM-D and a 26-item Manic State Scale (Beigel et al, 1971) done at monthly intervals. Serum lithium levels were carried out every 2 months. Thyroid function and routine blood tests were done every three months. Amount of concomitant thyroid supplement, antidepressant, neuroleptic and/or minor tranquilizers taken by the patient during the two-year study period in the study and two- year period prior to the entry of the study were compared. 2. 2. Eight patients completed the 2-year study period. Their mean serum lithium level (mean ± SD: 0.81 ± 0.16mmol/L) at the end of two years was identical with that at baseline. Six of these were maintained in a clinically stable state throughout with minor alterations in their lithium dosage only. Two patients had recurrence of depressive symptoms (HAM-D score of 18 or more) requiring significant readjustment of their antidepressant medication. Two patients were discontinued prematurely because they had manic episodes and required hospitalization. 3. 3. In conclusion, 60 percent of the patients remained stable while taking lithium every other day and did not have clinically significant worsening of Mania or Depression while 40 percent had a clinical relapse during the study period. These findings should be viewed in the context of recent literature suggesting a) that chronic lithium treatment using the traditional dosage regimen, does not cause permanent or serious renal damage (Waller and Edwards, 1995) and b) interrupted lithium treatment decreases the effectiveness of lithium prophylaxis (Maj and Pirozzi, 1995).