Med/Psych Update

Ketamine for acute catatonia: A case report

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References

Beware of the potential risks

Although ketamine may be clinically useful, it also carries some risks. Adverse effects associated with ketamine include sedation, dissociation, hallucinations, elevated blood pressure, nausea, increased heart rate, vomiting, dizziness, fatigue, blurred vision, itching, and emesis. Clinicians also should be aware that some patients may use illicit ketamine, either as self-treatment to control depressive symptoms or for recreational purposes. When misused/abused, long-term use of ketamine can cause neurologic damage.19 Studies also have reported rare occurrences of recurrent hallucinations even after discontinuation of ketamine.20 Animal studies have demonstrated addiction and cognitive deficits with repeated use of ketamine in rodents.21 This research has led to concerns that chronic use of ketamine to treat illnesses such as depression might lead to similar long-term adverse outcomes.

Dosing

As a sedative, IV ketamine dosing is generally 1 to 2 mg/kg, and IM ketamine dosing is 3 to 5 mg/kg.16 As an antidepressant, small clinical trials have suggested that the preferred dose of IV ketamine may be 0.5 to 1 mg/kg, with dose-dependent increases in dissociation and blood pressure.21 Studies have also demonstrated that once-daily IV ketamine, 0.5 mg/kg administered over 40 minutes, led to greater improvements in patients with MDD than placebo, whereas once-daily IV ketamine, 0.2 mg/kg, did not.20

CASE CONTINUED

The team begins to treat Ms. C with IV ketamine. Ketamine, 0.2 mg/kg, is used to calculate the initial dose, and a total of 10 mg is administered over 10 minutes. Fifteen minutes after administration, Ms. C is able to move around in her bed, make eye contact, and nod to questions. She has purposeful movements, such as examining her IV line, scratching her head, and repositioning herself in the bed. After a few more minutes, she makes eye contact with her father, and nods to him during conversation. She is able to make a few noises but does not speak.

Later that day, Ms. C is discharged home (in a wheelchair) with her parents, on a medication regimen of fluvoxamine, 100 mg/d; lorazepam, 1 mg 4 times a day; and olanzapine, 5 mg/d. She is scheduled for an outpatient follow-up appointment 5 days later. Her parents are given instructions and several precautions to ensure that Ms. C receives proper nutrition until her appointment. That evening, Ms. C is able to eat voluntarily.

Five days later, Ms. C visits the outpatient psychiatric clinic and is verbal and ambulatory. Her father reports that she has become more verbal. During her follow-up interview, she is observed to be more subdued and less verbal than her baseline, but is vocal and able to voice her understanding of the treatment plan.

Continue to: After 3 months of being stable...

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