Timing anti-nausea medicine around a chemo infusion

This page is for people taking anti-nausea medicines (antiemetics) during chemotherapy. It explains why the timing matters, the patterns of nausea, and when to call your team.

The instinct is to keep the tablets for when you actually feel ill. With treatment-related sickness, that is the wrong way round.

NCI puts it plainly. You will usually receive antinausea medicines before chemotherapy starts, because once nausea and vomiting from chemotherapy develop, they are more difficult to treat. The medicine is there to stop the problem starting, not to rescue you once it has.

So the schedule your team gives you is the treatment. Taking a dose late, or skipping one on a day you happen to feel fine, undoes the point of it.

Your doctor does, and NCI says so directly. Your doctor will also tell you when to take the antiemetics, such as before or after chemotherapy treatments or a certain amount of time before eating.

That last phrase is easy to miss. Some anti-sickness medicines are timed against your meals, not against your infusion. If nobody has told you which of yours is which, ask.

NCI also notes that your doctor may prescribe more than one type of antiemetic, depending on how bad the sickness is. Several drug groups are used, including serotonin blockers, dopamine blockers, NK-1 blockers, steroids, benzodiazepines, antipsychotics and cannabinoids. A list of three or four tablets with different timings is normal, not a sign that something has gone wrong.

Ask for the schedule written down, hour by hour, with each tablet named. Memory is not reliable on a treatment day.

NCI names the patterns, and each one explains part of the schedule.

• Acute sickness happens within 24 hours after treatment starts.
• Delayed sickness happens 1 to 7 days after treatment. It is also called late nausea.
• Anticipatory sickness happens before treatment begins. If an earlier session made you sick, the smells, sights and sounds of the treatment room can set it off next time.
• Chronic sickness carries on after treatment ends.

NCI says nausea and vomiting from chemotherapy usually last 24 to 48 hours, though some people feel sick for up to 7 days after treatment. That is why medicines are often prescribed to cover days when the infusion is already behind you.

Anticipatory nausea is the one people are most embarrassed to report. It is a recognised effect with a name, not something you are imagining.

There are words for this too, and using them helps your team act.

NCI describes breakthrough nausea and vomiting as happening within 5 days of starting antinausea treatment. Refractory nausea and vomiting are those that do not get better with antinausea medications.

Either one is a reason to ring the clinic rather than wait for the next appointment. The plan can be changed — a different drug group, a different timing, or an extra medicine added.

NCI's own tips are practical:

• Sip water or clear liquids through the day.
• Try cold foods such as popsicles, pudding, yogurt and gelatin, or bland starchy foods such as toast, rice, plain pasta, crackers and pretzels.
• Avoid greasy, fried, sweet or spicy food if it makes you feel worse.
• Keep away from strong smells while eating, and ask someone else to cook if food odours bother you.
• Eat five to six small meals rather than three large ones.
• Rest upright for 30 minutes after eating.

Keeping a short record of when you felt sick, and what you ate or did beforehand, gives your team something concrete to work from.

If you want to try a supplement or a complementary therapy for sickness, NCI says check with your doctor first. Some can make cancer treatments work less well.

• Call 911 or go to an emergency department if someone who may be dehydrated becomes confused or less alert, or has a seizure. MedlinePlus lists any change in alertness with dehydration as a reason to call 911 (MedlinePlus). Do not drive yourself.
• Call your care team right away, at any hour, if you are dizzy or weak. NCI lists these, and confusion, as signs of dehydration.
• Call your care team the same day if you cannot keep fluids down, or you vomit up an anti-sickness tablet and do not know whether to repeat it.
• Call your care team within a day or two if the sickness is not settling on the prescribed schedule, or it is still there beyond the 24 to 48 hours NCI describes.

• NCI — Nausea and Vomiting and Cancer Treatment