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.