Long-term sequestration of fluorinated compounds in tissues after fluvoxamine or fluoxetine treatment: a fluorine magnetic resonance spectroscopy study in vivo.

Fluorine magnetic resonance spectroscopy (19F MRS), spectroscopic imaging (MRSI) and proton anatomical magnetic resonance imaging (1H MRI) were performed on brains and lower extremities of six subjects in vivo concurrently with HPLC of serum to investigate tissue and plasma drug localization and withdrawal kinetics in humans treated with fluvoxamine or fluoxetine. 19F MRS signal was unexpectedly detected in the lower extremities months after complete disappearance of signal from plasma and brain. MRSI suggested that the lower extremity fluvoxamine signal originated mainly from bone marrow. Results suggest long-term sequestration of these drugs or their metabolites mainly in bone marrow and possibly in surrounding tissue and demonstrate the usefulness of MRS to reveal drug-trapping compartments in the body.