4. Individuals whose treatment dosage changes 2 months prior to, or during, the study for antihypertensive and antidiabetic medications and the following medications that may affect the autonomic nervous system: anti-tuberculosis drugs, nitrofurantoin, metronidazole, chloramphenicol, perhexiline maleate, cordarone, clofibrate, tricyclic antidepressants, phenytoin, barbiturates, neuroleptic drugs, antiparkinsonism drugs, and nitrated drugs.