Ketamine, a popular but dangerous club drug, is slowly returning to surgical suites as a safe anesthetic for surgery. "Special K," its street name, was originally developed as a human anesthetic in the 1960s. Today, it is most commonly used as an anesthetic for children and for patients in poor health. It has also become popular with veterinarians for animal anesthesia.
The drug became part of the club scene in the 1980s because of its PCP- and LSD-like hallucinogenic effects. Its "street" use died out after it became known for its unpredictabile "bad trips" but reemerged in the mid-1990s after ecstasy became popular. Emergency room visits caused by the drug's recreational use increased 10 fold from 1994 to 2000. Some deaths have been reported in connection with the drug when used in recreational settings.
Clinically, ketamine works by blocking the N-Methyl D-Aspartate (NMDA) receptors of the spinal cord, not allowing pain sensations to move above mid-brain levels, according to Barry L. Friedberg, MD, a volunteer instructor in clinical anesthesia at the University of Southern California in Los Angeles. He is an advocate of the drug because of its safety record.
To help patients deal with pain during surgical procedures, most anesthesiologists administer opioids like morphine, which have a major drawback: they depress the patient's drive to breathe. "Not surprisingly, respiratory complications are the number one cause of anesthetic mishaps in a clinical setting. Ketamine, on the other hand, supports the breathing drive and increases the life-preserving reflexes, Friedberg explained. "It's also a bronchial dilator and helps open up the lungs."
In medical preparations for surgical use, ketamine is available in three strengths: 5 mg, 50 mg, and 100 mg/cc. Surgical patients typically receive a 50 mg dose, which gives physicians a 10- to 20-minute window of opportunity for a short procedure in the ER or to inject patients with a local anesthetic for a longer procedure in an OR.
Patients do not have a reason to respond to pain because they are not receiving any impulses in their brain once the surgeon begins the surgery. "It's a one-two deal," he said."It is painful to inject patients with local aneathesia. By eliminating the painful stimulus to the brain, we can add local anesthesia without negatively impacting the brain," he said.
Teens have been attracted to the drug over the years because of its hallucinogenic side effects. The stigmata of the recreational use of ketamine has to some extent led to the reluctance of anesthesiologists to use it for surgical anesthesia. When properly used in a clinical setting, however, the drug produces no side effects the patient experiences or can recall afterwards.
That is not to say the drug is without its own unique set of problems. An unpredictable 20 percent of adults had adverse psychotropic responses-hallucinations or near-death experiences-when the drug was first used in medical settings in the '60s. Because of those early experiences, many anesthesiologists are uninterested in even administering the drug today.
"A fundamental aspect for anesthesiologists is the unpredictability issue," said Friedberg. "Anesthesiologists want to know if they give drug X at dose Y, the outcome is effect Z." The unpredictability issue has been effectively dealt with since the advent of the bispectral index (BIS) monitor, which received FDA approval as a monitor of depth of hypnosis or sleep in 1996. By using this monitor, anesthesiologists "are able to assign a numerical value at which we can absolutely guarantee no negative effects," he added.
"The reality is ketamine is a very effective, safe and reproducible drug," he said.
Ultimately what doctors provide patients by using ketamine is a kinder, gentler anesthesia and a less painful experience. In what Friedberg characterizes as a "mini-trend," an increasing number of physicians are gaining some experience with ketamine, and the use of the drug has been adapted to an increasing array of complex surgical procedures. In fact, in some medical care centers, it is being used in open heart surgery. "It's a question of trying to recognize there is another technique to get better patient outcomes," Friedberg said.
BEAUTY AND BEAST
Cosmetic surgery is one arena where the drug has especially found some followers. Cosmetic surgery is mainly performed in a surgeon's office as opposed to a hospital setting, and the issue of patient safety is a number one concern because there are fewer caregivers on hand to handle any patient emergencies. "Ketamine is the safest drug we've ever had," said Friedberg. In fact, he considers ketamine to be among the most effective pain blockers available for cosmetic patients, all of whom receive a local anesthetic.
Friedberg began using ketamine in clinical settings in 1992. In 1997, he incorporated the BIS monitor to his practice, and he can now measure how asleep patients are. In the process, he discovered he uses less propofol on his patients. This not only eliminates unnecessary drug use but also speeds the recovery and discharge of the patient, which increases the efficiency of all venues of surgery: office, free standing surgery centers and hospital day units.
"The safety profile of ketamine is unparalleled," he said. Too many people have died from overdoses or reactions to narcotics after surgical procedures in traditional clinical settings over the years, although the use of equipment like pulse oximeters to monitor has enhanced patient safety in more recent years. By contrast, there have been no deaths reported in the anesthesia literature traced to ketamine used in clinical doses since 1964, he said.
Ketamine shows two distinct personalities, depending on where it is used. In a clinical setting, the patient receiving ketamine is already unconscious and either does not experience or cannot recall any hallucinations. On the street, "people who use it take it while they are conscious to experience the hallucinogenic effects," Friedberg said. The hallucinations are a side effect of the ketamine, which is a second-generation PCP.
Occasionally ketamine is injected for street use. More often, teens evaporate the liquid form in which ketamine is sold on the street and snort the crystals. Overuse in this manner can cause disruptions in consciousness and lead to neuroses or mental disorders. At the same time, Special K can cause tremendous psychological dependence, and there are some reported cases of addiction. Overdoses of ketamine can also lead to heart attacks and strokes.
At a 50 mg dose, ketamine produces a near death experience. At a 100 mg dose, it produces an out of body experience. When ketamine is bought on the street, both dosage and purity come into question. The ingestion of an unknown quantity and purity of ketamine is extremely dangerous, especially if combined with alcohol, Valium, rohypnol or GHB. Ketamine is part of a class of drugs called dissociative anesthetics, a category that includes PCP.
Teens have also been using another street drug, ecstasy, and ketamine together, increasing the risks. "Teens are taking ecstasy first to make sure they have a good experience on ketamine," he said.
You can reach Caroline Crispino at email@example.com.