What is the best antiemetic (anti-emetic) for patients with prolonged QT (QT interval) syndrome?

From the Guidelines

For patients with prolonged QT interval syndrome, the best antiemetic option is typically prochlorperazine (Compazine) 5-10 mg every 6-8 hours, as it does not have a significant risk of further prolonging the QT interval, unlike ondansetron 1. When considering antiemetic therapy for patients with prolonged QT interval syndrome, it is crucial to choose medications that do not exacerbate the condition.

• Ondansetron, a 5-HT3 receptor antagonist, is associated with a risk of prolonged QTc interval 1 and should be avoided.
• Prochlorperazine, a dopamine receptor antagonist, is a suitable alternative, with a recommended dosage of 5-10 mg every 6-8 hours 1.
• Promethazine, another option, should be used with caution due to its potential to cause CNS depression, anticholinergic effects, and extrapyramidal symptoms 1.
• It is essential to monitor the patient's QTc interval regularly, especially when administering multiple medications that may have a potential impact on the QT interval.
• Consulting with a pharmacist to review the patient's complete medication list for other potential QT-prolonging drugs that could be discontinued or substituted is also recommended. The mechanism of action of prochlorperazine, as a dopamine receptor antagonist, makes it an effective antiemetic option for patients with prolonged QT interval syndrome, without the added risk of further prolonging the QT interval 1.

From the Research

Antiemetic Options for Patients with Prolonged QT Syndrome

• The choice of antiemetic for patients with prolonged QT syndrome should be guided by the risk of QTc prolongation associated with each medication 2.
• Certain antiemetics, such as 5-HT3 receptor antagonists (e.g., ondansetron, dolasetron), have been associated with QTc prolongation, although the risk may be lower than previously thought 3, 4.
• A study found that perioperative doses of ondansetron or dolasetron did not significantly lengthen the QT interval in patients undergoing noncardiac surgery 4.
• However, other studies have reported that ondansetron and other antiemetics can prolong the QTc interval, particularly in patients with underlying risk factors for QTc prolongation 5, 6, 3.

Factors to Consider When Selecting an Antiemetic

• Patient-specific factors, such as underlying heart conditions, electrolyte imbalances, and concomitant medication use, should be taken into account when choosing an antiemetic 2, 5, 6.
• The mechanism of action of the antiemetic, as well as its potential for drug interactions, should also be considered 5, 3.
• Close monitoring of the patient's ECG and QTc interval is recommended when administering antiemetics that may prolong the QTc interval 5, 6.

Alternative Antiemetic Options

• Other antiemetics, such as anticholinergics, antihistamines, and antidopaminergics, may be considered for patients with prolonged QT syndrome, although their efficacy and safety profiles should be carefully evaluated 2.
• Dronabinol and medical marijuana may also be considered as alternative antiemetic options, although their potential effects on the QTc interval are not well established 2.