If a patient vomits after taking under the tongue dissolving Zofran (ondansetron), does it still work?

Sublingual Ondansetron Remains Effective Even If You Vomit Shortly After Taking It

Yes, sublingual (under-the-tongue) dissolving ondansetron (Zofran) will still work even if you vomit after taking it, because it is absorbed directly through the oral mucosa within minutes and does not require swallowing or gastrointestinal absorption. 1

How Sublingual Ondansetron Works

• Sublingual ondansetron dissolves instantaneously in saliva and is absorbed directly through the mucous membranes of the mouth, bypassing the need for gastrointestinal absorption entirely 2
• The medication disperses rapidly in the oral cavity and enters the bloodstream through the rich vascular network under the tongue and in the cheeks 2
• Peak plasma levels are achieved within 10 minutes of administration, meaning the drug is already systemically absorbed before most vomiting episodes would occur 3

Why This Formulation Was Specifically Designed for Vomiting Patients

• The oral dissolving tablet (ODT) formulation was specifically developed for patients who have difficulty swallowing or are actively vomiting, making it ideal for situations where traditional oral medications would be lost 2, 4
• This formulation is particularly valuable for patients with nausea and vomiting who cannot tolerate standard tablets that require swallowing 2
• In prehospital emergency settings, the ODT formulation demonstrated significant efficacy (mean nausea score reduction of 3.3 points on a 10-point scale) despite being used in actively nauseated and vomiting patients 5

Clinical Evidence Supporting Effectiveness

• Multiple antiemetic guidelines recommend ondansetron ODT as equivalent to intravenous formulations for preventing chemotherapy-induced and radiation-induced nausea and vomiting 1
• The sublingual formulation has been shown to be completely absorbed with plasma concentration-time profiles comparable to intravenous administration, confirming that oral mucosal absorption is as effective as direct venous delivery 3
• In cyclic vomiting syndrome management, sublingual ondansetron is specifically recommended as an abortive therapy even when patients are actively retching and vomiting 1

Practical Considerations

• Allow the tablet to fully dissolve under your tongue (typically 30-60 seconds) rather than swallowing it immediately to maximize mucosal absorption 1
• Do not eat or drink for a few minutes after the tablet dissolves to allow complete absorption 2
• If vomiting occurs within the first 1-2 minutes of placing the tablet, before it has fully dissolved, you may need a repeat dose 1
• The typical adult dose is 8 mg, which can be given as a single 8 mg ODT or as an 8 mg oral soluble film 1

When Sublingual Route May Not Be Sufficient

• In severe, intractable vomiting where oral mucosa contact time is extremely limited (vomiting within seconds of administration), alternative routes may be needed 1
• For patients with cyclic vomiting syndrome who cannot abort episodes at home with sublingual medications, intravenous ondansetron in the emergency department becomes necessary 1
• Rectal formulations of other antiemetics (promethazine, prochlorperazine) or subcutaneous/nasal spray formulations of other medications may be considered as alternatives when sublingual route fails 1