"Currently, pharmaceutical treatment for substance abuse addiction in the United States is limited to two basic types: (1) replacement therapy; and (2) aversion therapy.21 Replacement therapy is characterized by substituting or replacing the drug that the person is addicted to with a “safer drug” under the theory that the individual can be weaned off the replacement drug over time.22 The most prominent examples of this are methadone maintenance for heroin addiction and nicotine replacement drugs for smokers.23 Unfortunately, there are no “safer drugs” available for individuals with addictions to cocaine, crack, or methamphetamine.24"

"Aversion therapy, on the other hand, involves the use of drugs that interact negatively with the drug of addiction, such as disulfiram, which is used to treat alcoholism.25 This treatment choice posits that the individual will be deterred from using the drug to which they are addicted because, when combined with aversion drugs, it induces nausea, vomiting, and physical pain.26 The problems associated with these treatment methods, however, are numerous. Both require long-term treatment, which greatly increases the chance that an addict will quit treatment and return to using.27 Replacement therapy simply replaces one drug with another, and, as is the case with methadone, the “safer drug” is itself addictive. ... The unpleasant side effects associated with aversion therapy, however, result in many patients stopping treatment and relapsing.31"

Source

Donnelly, Jennifer R, "The Need for Ibogaine in Drug and Alcohol Addiction Treatment," The Journal of Legal Medicine (Schaumburg, IL: American College for Legal Medicine, March 2011), Vol. 32, Issue 1.