DISEASE CHARACTERISTICS: Histologically or cytologically proven refractory or recurrent nonhematologic malignancies Measurable or evaluable disease by radiographic or clinical examination

PATIENT CHARACTERISTICS: Age: 18 and over Performance Status: Karnofsky 70-100% Life Expectancy: Not specified

Hematopoietic: Absolute neutrophil count at least 2,000/mm3 Platelet count at least 100,000/mm3 Hepatic:

Bilirubin no greater than 1.5 mg/dL SGOT and SGPT no greater than 2.5 times upper limit of normal Albumin at least 3 g/dL Renal: Creatinine no greater than 1.5 mg/dL OR Creatinine clearance greater than 60 mL/min Neurologic: No concurrent neurotoxicities greater than grade 1 from previous chemotherapy No concurrent neuropathy greater than grade 1 Other: Not pregnant Effective contraceptive method must be used by fertile patients during and up to 2 months after study No serious uncontrolled medical illness No history of active inflammatory bowel disease, ileus, or other chronic malabsorption syndromes

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent isoniazid No concurrent rifampin Chemotherapy: At least 4 weeks since chemotherapy At least 6 weeks since nitrosoureas therapy At least 3 months since suramin therapy No prior carboxyamidotriazole Endocrine therapy: No concurrent steroids (except dose required for adrenal insufficiency) No concurrent tamoxifen Radiotherapy: No prior radiotherapy within 4 weeks of study Surgery: No prior total gastrectomy or total ileocolectomy Other: No concurrent therapy with H2 antagonists, barbiturates, calcium channel blockers, terfenadine, astemizole, cisapride, digitoxin, quinidine, amiodarone, carbamazepine, imipramine, or antacids No concurrent erythromycin