MERCK MANUALConsumer Version

Important: The authors, reviewers, and editors of this material have made extensive efforts to ensure that treatments, drugs, and discussions about medical practice are accurate and conform to the standards accepted at the time of publication. However, constant changes in information resulting from continuing research and clinical experience, reasonable differences in opinions among authorities, unique aspects of individual clinical situations, and the possibility of human error in preparing such an extensive text mean that other sources of medical information may differ from the information on this site. The information on this site is not intended to be professional advice and is not intended to replace personal consultation with a qualified physician, pharmacist, or other health care professional. The reader should not disregard medical advice or delay seeking it because of something found on this site.