Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of malignancy

- Must be undergoing active treatment for malignancy which may include hormonal
therapy (e.g., tamoxifen citrate or leuprolide acetate), but not radiotherapy
alone

- Fatigue score ≥ 4 on a verbal analogue scale of 0 to 10

- No untreated cancer-related anemia

PATIENT CHARACTERISTICS:

- Hemoglobin > 10 g/dL

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- Able to swallow pills

- No known allergy to dextromethorphan hydrobromide

- No patients known to be phenotypically poor metabolizers of CYP2D6

- No untreated hypothyroidism

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- Prior single-dose inhibitors (e.g., ranitidine or cimetidine) for hypersensitivity
prophylaxis allowed

- Erythropoietic growth factor therapy of > 8 weeks duration allowed

- No concurrent CYP2D6 inducers or inhibitors

- No concurrent monoamine oxidase inhibitors

- No other concurrent medications containing dextromethorphan hydrobromide

- No concurrent over-the-counter medication, herbal product, vitamin, food supplement,
or any other type of special product unless permission to continue use is obtained
from the Principal Investigator

- No other concurrent anticancer investigational agents or therapies