Ketamine-induced QTc interval prolongation

Long-term safety of ketamine and esketamine in treatment of depression

INTRODUCTION

Ketamine is an NMDA receptor antagonist that can produce rapid-acting antidepressant effects. Esketamine (Spravato), the S-enantiomer of racemic ketamine, was approved by the FDA for treatment-resistant depression in 2019. Here we review what is known about the long-term safety of both racemic ketamine and esketamine as therapies for psychiatric disorders.

AREAS COVERED

In this article, we conducted a safety review of ketamine and esketamine. In looking at ketamine and esketamine long-term safety effects, we considered data available from experimental studies and several phase-three clinical trials.

EXPERT OPINION

Based on available data, the most common side effects of ketamine/esketamine are generally transient, mild, and self-limited. These include dissociation, nausea, headache, elevated heart rate, and blood pressure. Treatment with esketamine may lead to an increased risk of lower urinary tract symptoms, such as dysuria or urgency. However, severe bladder pathology has not been reported among patients receiving doses of esketamine/ketamine in line with prescribing guidelines for depression. There is considerable data that ketamine at high doses can lead to long-term impairments in cognition. However, the esketamine clinical trials found that cognition generally remains stable or improves over time, suggesting that when used appropriately, there is no increased risk of cognitive impairment.

Treatment of Agitation With Lorazepam in Clinical Practice: A Systematic Review

Acute agitation is a frequent occurrence in both inpatient and outpatient psychiatric settings, and the use of medication to calm a patient may be warranted to mitigate the situation. Lorazepam is a benzodiazepine that is widely used for management of acute agitation. Despite its widespread use, there is remarkably little clinical evidence for the benefits of lorazepam in acute agitation. We performed a systematic review with focus on lorazepam, including all randomized clinical trials on lorazepam in mental and behavioral disorders, excluding studies on dementia and pediatric patients and in mixed conditions. A total of 11 studies met inclusion criteria, and all were in patients with mental and behavioral disorders. Most trials generally found improvements across a variety of outcomes related to agitation, although there was some disparity if specific outcomes were considered. In the five studies with haloperidol, the combination of lorazepam and haloperidol was superior to either agent alone, but with no differences between monotherapy with the individual agents. In the study comparing lorazepam to olanzapine, olanzapine was superior to lorazepam, and both were superior to placebo. As expected, the safety of lorazepam among the different studies was consistent with its well-characterized profile with dizziness, sedation, and somnolence being the most common adverse events. Based on this structured review, lorazepam can be considered to be a clinically effective means of treating the acutely agitated patient.

Prevalence of QTc Prolongation in Patients With Advanced Cancer Receiving Palliative Care-A Cause for Concern?

CONTEXT

Medications commonly used for symptom control along with other known risk factors have the potential to prolong ventricular repolarization as measured by the QT interval (the time from the start of the Q wave to the end of the T wave) on a standard electrocardiogram (ECG).

OBJECTIVES

To document the prevalence of a prolonged QT interval corrected for heart rate (QTc) interval in the palliative/oncology setting, compare automatic ECG QTc measurements with manual readings and identify any correlation between QTc prolongation and the use of drugs or other risk factors.

METHODS

A convenience sample of consecutive patients with cancer, admitted under or known to the palliative/supportive care teams in two metropolitan hospitals, and willing to provide an ECG recording and basic demographic information including QTc risk factors were included. Both automated and manually calculated QTc intervals were recorded. Multivariable analysis was used to determine risk factors independently associated with prolonged QTc intervals.

RESULTS

Of the 389 participants, there was a significant difference in mean QTc between sites using automated but not manual calculations. Manual readings were therefore used with predetermined cutoffs of 0.44 seconds (males) and 0.46 seconds (females). Seventy-two (18.5%) of the participants had a prolonged QTc with six (1.5%) having a prolongation of >0.50 seconds. At-risk drugs were being taken by 218 participants (56.0% of total cohort). Factors shown to be associated with QTc prolongation included age, gender, performance status, and hypocalcemia. No specific medication was associated with increased risk.

CONCLUSION

Although almost 20% of patients receiving palliative care had prolongation of QTc, the possibility of serious consequences appeared to be low despite the frequent occurrence of risk factors.