Orphan Medical, Inc. manufactured the drug Xyrem, a powerful central nervous system depressant that can cause serious side effects. The Food and Drug Administration (FDA) approved Xyrem for only two uses: the treatment of cataplexy (attacks of muscular weakness) and excessive daytime sleepiness in narcolepsy patients. In 2002, the FDA required that Xyrem carry a "black box" warning, which is the most serious warning placed on prescription medication labels.
In 2005, the federal government launched an investigation of Orphan focusing on the "off-label" promotion of Xyrem. The Food, Drug and Cosmetics Act (FDCA) prohibits the sale of "misbranded" drugs, which includes drugs bearing any information on the label not approved by the FDA. Although physicians may prescribe a drug for any condition, the FDA will not approve a label for any use it has not approved. In effect, this makes it illegal for pharmaceutical representatives to promote drugs for unapproved uses (off-label uses). Because their labels do not contain adequate instructions and warnings concerning the unapproved uses, such drugs are deemed to be misbranded.

Alfred Caronia, an Orphan pharmaceutical sales representative, was recorded promoting Xyrem for unapproved uses, and the government prosecuted him for illegal off-label promotion. After Caronia was sentenced to one year of probation, 100 hours of community service, and a $25 special assessment, he appealed, arguing that the misbranding provisions of the FDCA that prohibit off-label promotion are an unconstitutional restraint on speech. Is the government's prosecution of Caronia an unconstitutional violation of Caronia's First Amendment right of free speech? Explain why or why not.