Uncontrolled Vomiting or Diarrhoea — When It Becomes an Emergency

If you can keep small sips down and vomiting is not getting worse, call your team rather than going straight to emergency. They will ask how much you can keep down, whether there is blood, and whether you have a fever. If it has gone on for 24 hours without improvement, or if any of the red flag signs above appear, do not wait any longer — go to the emergency department. The call is to help your team assess; if they cannot reach you quickly and you are getting worse, go in without waiting for them.

Call your team before taking anything extra, even if you have anti-nausea tablets at home such as ondansetron (Emeset, Zofran) or metoclopramide (Perinorm). Taking more than you were given can cause its own problems, and it may also mask the worsening your team needs to assess. If you cannot keep any fluids down at all, a tablet may not reach your system usefully — which is another reason that a drip and hospital assessment may be what is actually needed.

Yes, and when they happen together the risk of dehydration is much greater than with either alone. Some chemotherapy regimens cause both. The 24-hour threshold applies just as strongly — and losing fluid from both at once means the danger point arrives sooner. Tell your team that you have both at the same time, because that changes how urgently they will ask you to come in.

The immediate step is intravenous fluids — a drip — to replace what you have lost more quickly than drinking alone can. Your team will also check blood tests to see how your kidneys and electrolytes are, and to rule out infection, which is a separate concern on chemotherapy. Anti-nausea medicine can be given through the drip to work even when you cannot keep tablets down. Most people feel significantly better within hours of starting fluids.