Calcitriol, Ketoconazole, and Dexamethasone in Treating Patients With Metastatic or Unresectable Solid Tumors

DISEASE CHARACTERISTICS: * Histologically confirmed solid tumor * Metastatic or unresectable disease * Standard curative or reliable palliative therapy is no longer effective OR does not exist * Brain metastases allowed provided they have been treated with surgery or radiotherapy AND are stable PATIENT CHARACTERISTICS: Performance status * ECOG 0-2 OR * Karnofsky 60-100% Life expectancy * More than 3 months Hematopoietic * WBC ≥ 3,000/mm\^3 * Absolute neutrophil count ≥ 1,500/mm\^3 * Hemoglobin ≥ 8 g/dL * Platelet count ≥ 75,000/mm\^3 Hepatic * AST/ALT ≤ 2.5 times upper limit of normal * Bilirubin normal * No unstable or uncompensated hepatic disease Renal * Creatinine ≤ 2 mg/dL * No unstable or uncompensated renal disease * No history of kidney, urethral, or bladder stones within the past 5 years Cardiovascular * Ejection fraction ≥ 30% * No symptomatic congestive heart failure * No significant arrhythmias * No myocardial infarction within the past 3 months * No unstable angina pectoris * No unstable or uncompensated cardiac disease * No other significant heart disease Pulmonary * No unstable or uncompensated respiratory disease Immunologic * No known severe hypersensitivity to ketoconazole or calcitriol or any of the excipients of these products * No history of allergic reaction attributed to compounds of similar chemical or biological composition to the study drugs * No ongoing or active infection Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception prior to, during, and for 3 months after completion of study treatment * Able to receive oral medication * No sperm donation during and for ≥ 3 months after completion of study treatment * No evidence of significant clinical disorder or laboratory finding that would preclude study participation * No other severe or uncontrolled systemic disease * No psychiatric illness or social situation that would preclude study compliance PRIOR CONCURRENT THERAPY: Biologic therapy * No concurrent prophylactic growth factors, including filgrastim (G-CSF) or sargramostim (GM-CSF) Chemotherapy * At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) * Any number of prior chemotherapy regimens allowed Endocrine therapy * No concurrent systemic glucocorticoid therapy \> physiologic replacement doses Radiotherapy * See Disease Characteristics * Any number of prior radiotherapy regimens allowed Surgery * See Disease Characteristics * Recovered from prior major surgery * Concurrent surgery allowed provided ≥ 7 days has passed since the last dose of ketoconazole (ketoconazole may be restarted after adequate wound healing) Other * Recovered from prior anticancer therapy * Alopecia allowed * More than 30 days since prior nonapproved or investigational agents * More than 7 days since prior and no concurrent thiazides * No concurrent combination antiretroviral therapy for HIV-positive patients * No concurrent digoxin or calcium supplementation * No concurrent proton pump inhibitor or H2 blockers * No concurrent medications that would alter the levels of ketoconazole and/or calcitriol, including the following: * Phenytoin * Carbamazepine * Barbiturates (e.g., phenobarbital) * Rifampin * Hypericum perforatum (St. John's wort) * No concurrent drugs that would be significantly impaired in a clinically important way by ketoconazole * No other concurrent investigational or commercial agents or therapies for this malignancy