"The state must demonstrate a legitimate interest to impair doctors’ rights to practice their profession. Historically, the interest asserted by the state is a health interest, and courts have upheld laws designed to ensure the quality of medical practice. Similarly, statutes have been upheld which require doctors’ intervention in sales of medically-related products in order to protect public health. None of the above interests are applicable here, however. The statute in question here does not protect the public from unqualified practitioners. Rather the statute applies to laymen and physicians alike. Indeed, it endangers patients’ health by unduly confining doctors’ exercise of medical judgment.... Further, the statute addresses no other legitimate state interest."