From the Guidelines
For an 88-year-old male patient on sertraline and dextromethorphan who is experiencing nausea, ondansetron (Zofran) would be the best antiemetic choice to minimize serotonin syndrome risk. A typical dose would be 4mg orally or sublingually every 8 hours as needed. Ondansetron works primarily on 5-HT3 receptors in the chemoreceptor trigger zone and has minimal impact on other serotonergic pathways, making it less likely to contribute to serotonin syndrome when combined with sertraline and dextromethorphan 1. Some key points to consider when choosing an antiemetic in this scenario include:
- Avoiding metoclopramide, promethazine, and other antiemetics with stronger serotonergic effects
- Considering discontinuing the dextromethorphan cough syrup if possible, as this combination with sertraline already poses some serotonin syndrome risk
- Monitoring the patient for signs of serotonin syndrome, including confusion, agitation, muscle rigidity, hyperthermia, and autonomic instability
- Discontinuing all serotonergic medications and seeking immediate medical attention if symptoms of serotonin syndrome develop The most recent and highest quality study, from 2017, supports the use of 5-HT3 antagonists like ondansetron for preventing nausea and vomiting 1. Other options, such as palonosetron, may also be effective, but ondansetron is a well-established and widely used choice for this indication 1. Overall, the goal is to minimize the risk of serotonin syndrome while effectively managing the patient's nausea.
From the FDA Drug Label
The development of a potentially life-threatening serotonin syndrome has been reported with SNRIs and SSRIs, including sertraline, alone but particularly with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, tryptophan, buspirone, and St John’s Wort) and with drugs that impair metabolism of serotonin (in particular, MAOIs, both those intended to treat psychiatric disorders and also others, such as linezolid and intravenous methylene blue). Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, delirium, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and/or gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea).
The best antiemetic to give without increasing the risk of Serotonin syndrome would be one that is not serotonergic. Options may include:
- Metoclopramide is not ideal as it can have serotonergic effects, although it is not as potent as other serotonergic agents.
- Ondansetron is a possible choice as it is not serotonergic, however its use should be cautious and monitored.
- Dopamine antagonists like prochlorperazine or haloperidol could be considered, but their use should also be cautious and monitored. It is essential to monitor the patient closely for any signs of serotonin syndrome when administering any antiemetic, especially in the presence of sertraline and dextromethorphan, which can both contribute to increased serotonin levels 2.
From the Research
Antiemetic Options
To manage nausea in a patient taking sertraline and dextromethorphan cough syrup without increasing the risk of serotonin syndrome, consider the following antiemetic options:
- Dopamine antagonists, such as metoclopramide, can be effective but may have side effects like extrapyramidal symptoms, particularly in children 3
- Antihistamines can be used, but their efficacy may vary depending on the cause of nausea 3
- Neurokinin antagonists, such as aprepitant, may be considered, but their use in this context is not well-established 3
Serotonin Syndrome Considerations
When selecting an antiemetic, it is crucial to avoid medications that may increase the risk of serotonin syndrome, a potentially life-threatening condition caused by excessive serotonergic activity 4.
- Serotonin antagonists, such as ondansetron, may seem like a viable option, but they can also contribute to serotonin syndrome in combination with other serotonergic agents like sertraline 4
- Therefore, it is essential to choose an antiemetic that does not significantly interact with sertraline or dextromethorphan to minimize the risk of serotonin syndrome 4
Treatment Approach
The treatment approach should be based on the suspected cause of nausea and the patient's medical history 5, 6.
- A careful evaluation of the patient's symptoms, medical history, and current medications is necessary to guide the selection of an appropriate antiemetic 5, 6
- Non-pharmacologic management options, such as fluid and electrolyte replacement, small frequent meals, and avoidance of trigger foods, should also be considered 5