Risk of exposure of patients' family members to lenalidomide at home.

Objectives: Lenalidomide, a hazardous drug, has strict distribution controls. However, the risk of contamination with lenalidomide when patients take the drug has not been studied and the risk of drug exposure to people in the patient's living environment is unknown. Thus, we investigated the amount of lenalidomide that could be dispersed during the period between removal of the capsule and returning the used blister packages, and we considered the conditions under which lenalidomide could be dispersed and countermeasures.

Methods: The amount of lenalidomide contamination was measured on the outside of the unused blister packages returned by the patients, on the surface of the capsule, and on the inside of the package immediately after removal of the capsule. In addition, the amount of contamination was measured on the blister packages used by the patients and on the gloves worn by the pharmacists on receipt of the packages. Lenalidomide was analysed by liquid chromatography-tandem mass spectrometry.

Results: Lenalidomide amounts on the outside of the unused blister packages returned by the three patients were <10, <10, and 26.8 ng/pack, those on the capsule surface immediately after removal from the packages were 297, 388, and 297 ng/capsule, and those on the inside of packages immediately after removal of all capsules were 143, 184, and 554 ng/pack, respectively. A median of 15.6 ng/pack lenalidomide was detected on the surface of packages used by the patients (n=18). The lenalidomide remaining in the packages immediately after capsule removal (~200 ng/pack), except for the 15.6 ng/pack detected in the packages used by the patients, may have been dispersed in the patient's living environment (~90% or more). The maximum amount of lenalidomide on the surface of the packages used by the patients was over 2500 ng/pack.

Conclusions: The amount of lenalidomide contamination per package was found to be at least 100 ng less after collection by the pharmacist than immediately after removal of the capsules. Therefore, it is recommended to clean the surrounding area and wash one's hands after taking the capsules.