Pre-medication before the infusion starts

Medicines to stop you feeling sick, to reduce the chance of a reaction, and sometimes to protect the kidneys or the bladder. They go in first, usually through the same drip, and they are the reason the day starts slowly rather than with the chemotherapy itself.

This matters to know because of one thing in particular: the drowsiness people feel in the chair is almost always the pre-medication, not the chemotherapy. Families frequently conclude that the treatment has hit hard within minutes. It has not.

How long it takes

This is the part that stretches the day. The pre-medication has to run through before the chemotherapy can start, and with some schedules there are fluids before and after as well. People often arrive expecting the whole visit to take as long as the chemotherapy bag, and find that bag is the shortest thing they are given.

Why it is given before rather than after

Anti-sickness medicine works far better when it is already in the system before the chemotherapy arrives. The same is true of the medicines that reduce reactions. Waiting to see whether you need them defeats the purpose, which is why everyone gets them whether or not they felt sick last time.

Because antihistamines and some anti-sickness medicines are sedating, and they are given first. People often fall asleep before the chemotherapy has even started running, and then conclude the chemotherapy knocked them out within minutes.

Why the distinction matters

It changes what you expect. Chemotherapy side effects usually build over the days that follow rather than arriving in the chair. If you know the drowsiness is the pre-medication, the first evening going reasonably well does not become a false reassurance, and the difficult days two or three days later are not a shock.

It also explains the driving advice

You are being given sedating medicines, sometimes without anyone spelling that out. That is why driving yourself home is discouraged, particularly after a first cycle when you do not yet know how strongly they affect you.

Sleeping through it is fine

Many people sleep through a large part of the infusion and wake when it finishes. The nurses are checking on you throughout, and there is nothing you need to stay awake for. Take something warm, because sitting still and asleep in an air-conditioned room gets cold.

It cannot tell you what you will be given. Pre-medication is chosen around the specific chemotherapy drugs you are having, how strongly they cause sickness, and whether they carry a risk of reaction. Two people in the same room will often be given quite different things.

It also cannot tell you how it will affect you. Some people are barely drowsy and some sleep through the afternoon. Nothing here should be used to start, stop or change anything you have been prescribed, including tablets to take at home before a cycle.

What to do next

Ask what your pre-medication is and what each part is for, and write it down. Ask whether you have any tablets to take at home beforehand. Arrange a lift home rather than driving. And take something warm, because you may well sleep through part of the day.