Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed advanced solid tumor refractory to standard therapy or for
which no standard therapy exists

- Measurable or evaluable disease

- No CNS primary tumor or metastasis

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Karnofsky 60-100%

Life expectancy:

- Not specified

Hematopoietic:

- WBC greater than 3,500/mm^3

- Neutrophil count at least 1,500/mm^3

- Platelet count at least 100,000/mm^3

Hepatic:

- Bilirubin no greater than 1.5 mg/dL

- AST and ALT no greater than 2.5 times upper limit of normal

Renal:

- Creatinine no greater than 1.5 mg/dL OR

- Creatinine clearance greater than 60 mL/min

Cardiovascular:

- No history of cardiac arrhythmias (including atrial fibrillation)

- No congestive heart failure

- No angina or myocardial infarction within the past 6 months

- QTc interval no greater than 0.48 sec

Other:

- Potassium at least 3.5 mEq/L

- Magnesium at least 1.4 mEq/L

- No mental incapacity that would preclude informed consent

- No serious or uncontrolled infection

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during and for 2 months after study
participation

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- At least 4 weeks since prior immunotherapy and recovered

Chemotherapy:

- At least 4 weeks since prior chemotherapy and recovered

Endocrine therapy:

- Not specified

Radiotherapy:

- At least 4 weeks since prior radiotherapy and recovered

Surgery:

- Not specified

Other:

- At least 2 weeks since prior herbal therapy for cancer and recovered

- No concurrent class IA or III antiarrhythmic agents (e.g., quinidine, procainamide,
disopyramide, sotalol, amiodarone, ibutilide, almokalant, or dofetilide)

- No concurrent tricyclic antidepressants (e.g., amitriptyline, doxepin, desipramine,
imipramine, or clomipramine)

- No concurrent antiseizure medication (including dilantin and phenobarbital) for any
underlying seizure disorder