THE EFFECT OF FLURBIPROFEN ON STEADY-STATE PLASMA LITHIUM LEVELS

Study Objective. To evaluate the effects of flurbiprofen therapy on th e pharmacokinetics of lithium. Design. Placebo-controlled, single-blin d, crossover study. Setting. University-affiliated hospital. Patients. Eleven healthy women with bipolar disorder. Interventions. The subjec ts received therapeutic doses of lithium administered as an immediate- release capsule every 12 hours. In addition, they received one placebo tablet every 12 hours during phase I and flurbiprofen 100 mg every 12 hours during phase II of the study. Measurements and Main Results. St eady-state pharmacokinetic parameters were measured for each phase. Li thium trough plasma concentration (C-min) and area under the curve wer e statistically significantly increased (p<0.05) when patients receive d flurbiprofen. Flurbiprofen also caused decreases in lithium clearanc e and 24-hour lithium urine excretion, although the changes did not re ach statistical significance. Clinically significant increases in C-mi n, appeared to be associated with a greater than 1000-mu g/24 hour dec rease in urinary excretion of prostaglandin E(2). Conclusion. Patients with clinically normal renal function may experience an increase in l ithium levels with the initiation of flurbiprofen therapy.