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