Fluoxetine and Norfluoxetine, Serum or Plasma

Red-top tube, lavender-top (EDTA) tube, or green-top (heparin) tube. Do not use a gel-barrier tube. The use of gel-barrier tubes is not recommended due to slow absorption of the drug by the gel. Depending on the specimen volume and storage time, the decrease in drug level due to absorption may be clinically significant.

The efficacy of fluoxetine in the treatment of nondelusional, moderately depressed patients is comparable to that of the tricyclic agents; its efficacy in severely depressed hospitalized patients has not been established. In limited studies, fluoxetine was useful in treating patients with atypical depression, panic disorder, and the depressed component of bipolar disorder. Fluoxetine may be indicated as initial therapy in patients with concurrent obsessive-compulsive disorder. Its efficacy in obesity and bulimia is being explored.

The selection of fluoxetine appears to be most appropriate for patients who are at special risk from sedative, hypotensive, and anticholinergic side effects caused by other antidepressants. In addition, it appears to be relatively safe for use in the elderly, although its very long elimination half-life may pose special problems for these individuals.