Managing Nausea in Infectious Mononucleosis
For nausea in infectious mononucleosis, start with metoclopramide 10-20 mg orally every 6 hours or prochlorperazine 5-10 mg orally every 6 hours, combined with adequate hydration and symptomatic care. 1, 2
First-Line Pharmacologic Approach
Dopamine antagonists are the preferred initial agents: metoclopramide 10-20 mg orally 3-4 times daily or prochlorperazine 5-10 mg orally every 6 hours provide effective antiemetic control through dopamine receptor blockade 1, 2
Monitor for extrapyramidal symptoms (dystonic reactions), particularly in younger patients—this is a critical pitfall since mononucleosis predominantly affects adolescents and young adults aged 15-24 years 1, 3
Have diphenhydramine available as rescue treatment for dystonic reactions, or benztropine if diphenhydramine allergy exists 1
Essential Supportive Care
Adequate hydration is fundamental: ensure fluid repletion and correct any electrolyte abnormalities, as dehydration commonly accompanies the fever and pharyngitis of mononucleosis 4, 5
Provide analgesics and antipyretics for the fever and sore throat that characteristically accompany infectious mononucleosis 5
Activity should be guided by the patient's energy level rather than enforced bed rest 5
Escalation for Persistent Nausea
Add ondansetron 4-8 mg orally every 8-12 hours (a 5-HT3 antagonist) to the dopamine antagonist rather than replacing it—combination therapy from different drug classes is more effective than switching 1, 2
Consider adding dexamethasone 4-8 mg orally daily for enhanced antiemetic effect if nausea remains refractory 1
Administer antiemetics around-the-clock rather than as-needed if nausea persists despite initial treatment 4, 2
Alternative Routes if Oral Intake Fails
If the patient cannot tolerate oral medications due to severe pharyngitis or persistent vomiting, switch to intravenous or rectal administration of antiemetics 4, 6
Metoclopramide can be given 10-20 mg IV every 6 hours, or prochlorperazine 5-10 mg IV every 6 hours 1
Critical Pitfalls to Avoid
Do not assume nausea is solely from mononucleosis: rule out other causes including medication effects (if any concurrent drugs), hepatitis (occurs in ~10% of mono cases with hepatomegaly), or other gastrointestinal pathology 1, 5
Avoid first-generation antihistamines like diphenhydramine as primary antiemetics—they cause excessive sedation without superior efficacy 1
Do not routinely use corticosteroids for uncomplicated mononucleosis; they are reserved only for respiratory compromise or severe pharyngeal edema, not for nausea management 5
Non-Pharmacological Adjuncts
Recommend small, frequent meals at room temperature rather than large meals 1, 2
Consider dietary consultation if nausea persists beyond the acute phase 2