Although the minimum effective dose of the once-a-day fentanyl citrate transdermal patch (tape) used for cancer pain is 1 mg, this may be excessive depending on the patient＇s condition. The dosage may be lowered using film dressing because the tape cannot be cut and patched; however, the feasibility of dose adjustment using this method is not confirmed. The tape was covered with OPSITE ＊ FLEXIFIX (OP), PERME-ROLL (PE), or Tegaderm TM Roll (TE) as film dressings, adopting 2 methods: (1) bonding the application surfaces of the tape and film dressing; or (2) pasting the tape on the surface of the film dressing. From the results of the drug release test and skin permeability test, OP was found to prevent drug release more markedly when adopting method (1). During hospitalization at the Ashiya Municipal Hospital, the tapes were applied in the following dosages to each patient: A (1 mg and 0.5 mg), and B-D (0.5 mg). Administration of 0.5 mg was performed using PE with method (2). The residual rate for each patient was: A: 80.6％, B: 74.6 ± 8.39％, C: 75.6 ± 4.37％, and D: 79.4 ± 8.31％. When the tape at 1 mg was attached to patient A, the residual rate was 61.1 ± 9.50％. These results support the feasibility of dose adjustment by covering the drug releasing surface of the tape with appropriate film dressing, such as OP or PE, adopting method (2).