Actor Matthew Perry died from an overdose of the drug ketamine nearly a year ago. Five people have now been charged in connection with the death of the “Friends” star. While the misuse and abuse of ketamine was blamed for his demise, experts say that when used correctly, ketamine is a valuable therapy for treatment-resistant depression.

According to HuffPost,  Dr. John Krystal, chair of the department of psychiatry at Yale School of Medicine in Connecticut explains that if a patient tries two or more different common antidepressants and does not get symptomatic relief, he or she may be a candidate for ketamine.

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The most prescribed drugs to treat the symptoms of depression are called selective serotonin reuptake inhibitors, or SSRIs, and serotonin and norepinephrine reuptake inhibitors, or SNRIs. These medications take six to eight weeks to work and target the neurotransmitters norepinephrine and serotonin in the brain. 

“Ketamine targets a different chemical system in the brain, called the glutamate system, which provides the information pathway for the networks in the brain involved in the regulation of mood and cognition,” said Krystal. In some patients, it works faster than SSRIs or SNRIs.

Ketamine is approved by the Food and Drug Administration (FDA) as a treatment for depression in its nasal spray form. This is known as esketamine. It’s a highly regulated Schedule III controlled substance and both patient and clinic must be enrolled in the REMS program. REMS stands for “risk evaluation and mitigation strategy,” explains Dr. Paul Kim, the director of the Johns Hopkins Treatment Resistant Esketamine Antidepressant Targeted Depression Clinic in Baltimore.

Ketamine that is administered intravenously is approved by the FDA only as an anesthesia drug. However, Kim said it can also be used off-label to treat depression. Unlike other medicine for depression, such as Zoloft and Prozac, ketamine and esketamine are not administered daily. The patient may receive treatment a few times a week and then less frequently. Ketamine therapy may also be paired with a daily antidepressant pill. Ketamine is also available in a compounded pill that is taken orally.

Experts warn that its important for patients taking ketamine therapy to be monitored in a clinical setting. In Perry’s case, the amount of ketamine found in his blood was equivalent to what doctors prescribe for anesthesia, says the Los Angeles Times. His assistant, Kenneth Iwamasa, said the actor instructed him to “shoot me up with a big one,” in the hours prior to his death, referring to an injection of the drug. When Iwamasa returned to Perry’s home after running errands, Perry was dead, floating face down in the Jacuzzi.

Krystal said that a study found that a high percentage of patients who use ketamine at home misuse the drug. “If it’s being misused, then there’s always the potential that it can become deadly,” said Krystal. Misuse can also lead to addiction, say experts. Since IV ketamine isn’t approved by the FDA, it must be paid for out of pocket, which can be very expensive.

On the flip side, ketamine can be a lifesaver when properly used to prevent or reduce the risk of suicide. The bottom line is that if your therapist approves ketamine therapy for depression, seek out a properly run clinic, preferably under the watchful eye of a psychiatrist. It’s important to remember that ketamine is not a cure for depression, but it can improve symptoms.

You should be monitored by a mental health professional who can best assess symptoms, treatments and overall health outcomes to ensure success and safety when using ketamine.