Flavopiridol in Treating Patients With Recurrent or Metastatic Head and Neck Cancer

head and neck cancer, thromboembolism, untreated metastatic squamous neck cancer with occult primary, recurrent metastatic squamous neck cancer with occult primary, metastatic squamous neck cancer with occult primary squamous cell carcinoma, stage iv squamous cell carcinoma of the lip and oral cavity, recurrent squamous cell carcinoma of the lip and oral cavity, stage iv squamous cell carcinoma of the oropharynx, recurrent squamous cell carcinoma of the oropharynx, stage iv squamous cell carcinoma of the hypopharynx, recurrent squamous cell carcinoma of the hypopharynx, stage iv squamous cell carcinoma of the larynx