 - Women must not be pregnant or breast feeding; pregnant women are excluded from this study; women of child-bearing potential and men must agree to total abstinence or to use adequate hormonal or barrier method of birth control prior to study entry and for the duration of study participation; should a woman become pregnant or suspect she is pregnant while in this study, she should inform her treating physician immediately; all females of childbearing potential must have a blood test or urine study within 2 weeks prior to randomization to rule out pregnancy 