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U.S. Department of Health and Human Services

Animal & Veterinary

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FDA Veterinarian Newsletter May/June 1999 Volume XIV, No III

As a follow-up to the article titled "Regulation of Controlled Substances" featured in the March/April 1999 issue of the FDA VETERINARIAN, this new information is now available.

In the April 9, 1999, Federal Register (64 FR 17299), the Drug Enforcement Administration (DEA) proposed the placement of the substance ketamine, including its salts, isomers, and salts of isomers, into Schedule III of the Controlled Substances Act (CSA).

The effect of this proposed action will be to discourage the diversion and abuse of ketamine, and subject ketamine to the regulatory, civil and criminal controls of a Schedule III controlled substance.

Ketamine hydrochloride has been marketed in the United States since 1971 as a rapid-acting general anesthetic, for both human and veterinary medicine. It can produce a unique anesthetic state characterized by sedation, immobility, marked analgesia, and amnesia. Chemically, ketamine is related to PCP, a Schedule II controlled substance. The effects produced with use of ketamine are similar, although less intense and shorter in duration, to those produced by PCP.

The pharmacological and behavioral effects of ketamine are similar, but somewhat less intense and shorter in duration, to those of PCP. Low dose intoxication with ketamine results in impaired attention, learning, and memory functions. Higher doses may result in ataxia, dizziness, elevated blood pressure, mental confusion, hyperexcitability, catalepsy (the inability to move), convulsions, a delusional dream-like, hallucinations, and psychosis. Long-term use of ketamine is associated with hallucinatory flashbacks and as inability to concentrate. Several case reports suggest that psychological dependence and tolerance develop in humans after long-term use of ketamine. Behavioral and physical dependence have been demonstrated in animals.

In 1981, The Department of Health and Human Services (DHHS) first recommended to the DEA that ketamine and products containing it be placed into Schedule III of the CSA, however, the DEA determined that the incidence of actual abuse was not sufficient to sustain the scheduling action. The DEA continued to monitor the situation, and incidents increased significantly until 1992, when 775 reports of ketamine diversion or abuse had been received by the DEA. The incidence of law enforcement encounters of individuals selling the drug, under its influence, or who had it in their possession, along with the wide geographic distribution of the encounters, the involvement of teenagers and young adults, the occurrence of veterinary clinic burglaries directed at ketamine, the spreading notoriety of ketamine as a party drug, "Special K'' or "K'', and the number of ketamine abuse-related hospital emergency department visits have caused the DEA to reconsider the noncontrolled status of the drug.

Ketamine is presently regulated as a controlled substance in 18 states; 15 states have placed it into Schedule III, two states have placed it into Schedule IV, and Massachusetts has designated it as a Class A substance.

Interested persons are invited to submit their comments, objections, or requests for a hearing, in writing, with regard to this proposal to the Deputy Administrator, Drug Enforcement Administration, Washington, D.C. 20537. Attention: DEA Federal Register Representative/CCR. Comments and objections must be received on or before June 8, 1999.