Backup insulin for pump users
A pump user has no long-acting insulin behind them, which is why a failure is urgent. What a written backup plan contains, and the supplies that quietly expire.
A pump user has no long-acting insulin in them. That single fact is why a pump failure is more urgent than most people expect, and why every pump user is supposed to have a written way back to injections.
- No pump delivery means no insulin at all within a couple of hours, not a gradual drift.
- Ketones can build quickly, so an unexplained high in a pump user is a reason to check them.
- You should have a written backup plan from your team, in your bag rather than in your head.
- That plan needs long-acting insulin that is in date, which is the part that lapses.
- The plan itself, and every number in it, is worked out with your diabetes team.
Nothing behind the pump
On injections, a long-acting dose is working in the background for many hours, so a missed mealtime dose is a problem but not a vacuum. A pump replaces that entirely with a continuous trickle of rapid insulin, which means the only insulin in you at any moment is the last hour or two of delivery.
Stop the delivery and that runs out fast. Glucose starts climbing sooner than people expect, and because there is no reserve, the body starts producing ketones sooner too. This is why the standard advice for pump users is that an unexplained high is a prompt to check ketones rather than to wait and see.
None of this makes pumps dangerous. It makes them a system with a specific failure mode, and the answer is a plan rather than caution.
What a backup plan actually contains
Every pump user should have been given a written plan for going back to injections. If you cannot lay hands on yours, that is worth fixing at your next contact with the team, because it is not something to work out during the failure.
A plan of this kind covers what long-acting insulin to use and how it relates to your pump settings, how to handle mealtimes on pens, when to check ketones and what result means calling them, and who to ring out of hours. Every number in it comes from your team and applies to you rather than to pump users generally.
Then keep it somewhere useful. A printed copy in your kit bag and a photograph on your phone means it survives a flat battery and a bad night. A plan that only exists in a folder at home is a plan you will not have when the pump fails on a Saturday.
The supplies that quietly expire
The plan is useless without the insulin it names. That means holding long-acting insulin even though you never normally use it, and that is exactly the thing that sits in a fridge for two years and expires unnoticed. Checking it on a schedule, alongside ketone strips and glucagon, is what keeps the plan real.
Alongside it: pen needles, a way to give rapid insulin if your pump is out of action, in-date ketone strips, and a meter with strips in case sensor data goes too. Pump users are often prescribed backup pens as a matter of course, and if you have never been given any, that is a straightforward ask.
Manufacturers usually operate a replacement service for a failed pump, often shipping within a day, so the gap you are covering is typically short. The point is to be covered for it rather than to improvise, and to know the manufacturer’s helpline number before you need it. Travelling raises the stakes, since a replacement pump cannot reach you abroad as easily, which is a reason to carry the backup rather than leave it at home.
What changes how much cover you need
Travel is the one that changes the answer most, because the replacement service that makes this simple at home does not follow you abroad. Living alone matters for a different reason: a failure overnight has nobody else to notice it. And a bank holiday can turn a one day gap into four.
Where the plan breaks
Examples, not instructions or doses.
Written properly and unavailable at the moment it was needed. A photo on the phone costs nothing and survives everything.
Held faithfully for two years and out of date. The insulin you never use is the one that lapses unnoticed.
An unexplained rise treated as a bad meal rather than a failed site. In a pump user that is the moment to check ketones.