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Missed dose of glargine insulin



My 16 year old daughter has Type 1 diabetes and was started on insulin glargine once a day and bolus lispro insulin for meals. She does well with her bolus insulin but occassionaly forgets her long acting insulin. What should she do – take her full dose of glargine when she remembers? reduce the amount of glargine by the same percentage as her “tardiness”, just cover with the fast acting insulin until the next scheduled glargine dose? Our physician`s responce is to find a schedule and make sure she takes her medication, but she is not always at home when her glarine is due. Seems like about every 2 months she “forgets”.


This is a common concern. It sounds easy to take medicine at the same time every day, but it can be challenging.

Why is it so important to take it at the same time every day? Insulin glargine (Lantus) is a time-release basal insulin. It works very very slowly. In order to have a stable amount of basal insulin, we must rely on a “carryover” of the previous dose and the new dose. If the new dose is taken more than one hour before or after the previous dose, the basal insulin level can be too low or too high. This will contribute to fluctuating blood glucose levels at all times of the day – not just when the new dose is taken.

Therefore – don’t think it’s hopeless – try to think of a time of day when the insulin glargine (Lantus) will be less likely to be forgotten, or when your daughter is always home. Many parents assume control of the insulin glargine dose for teens – and pick a time of day they are always with their teen and give it to them. It’s one less diabetes task the teen has to remember, and the priority for teens is that they know what to do for diabetes care – and do it – when they are away from home.

Insulin glargine can be taken at any time of the day or night, as long as it is the same time every day. If your daughter wants to keep her insulin glargine time in the evening – then she needs to take it with her if she is likely to be away from home when it is due. Encourage her to ask a friend to remind her, or to set the alarm on her cell phone to remind her. Now that insulin glargine can be given with an insulin pen, it is easier to carry it when out.

If a person forgets to take insulin glargine, and it is 4 or 6 or 8 or 10 hours later – there is no ideal method for getting back on track. Listed below is one approach – but keep in mind – no approach works as well as taking it on time! Until you are back to your usual time for insulin glargine, test blood glucose levels more often – every 3-4 hours, even during the night – and do high blood glucose corrections if above 150 mg/dl.

1. If it is less than 6 hours since the insulin glargine dose was due – take the normal dose of insulin glargine. Also test your blood glucose level – you are likely to be high, so take a blood glucose correction dose if needed. Then over the next few days – gradually move the time of the insulin glargine dose back to it’s normal time, one hour per day. For example – if you normally take insulin glargine at 8pm, but take it at 11 pm because you forgot it. Then the next night take it at 10 pm, then the next night take it at 9pm, etc. until you are back to your original time.

2. If it is more than 6 hours since the insulin glargine dose was due, it is better to skip the insulin glargine injection until the next day. Since you still need to have basal insulin – you will take ultra-short-acting insulin (insulin lispro/Humalog, insulin aspart/Novolog, insulin glylysine/Apidra) every 3-4 hours or short-acting insulin (regular insulin/Humulin or Novolin) to make up the basal insulin.

To figure out how much rapid-acting insulin to take – take your insulin glargine dose and divide it by 24. This equals how much basal insulin you need every hour. Multiply that number by 3, 4 or 6 to determine how much rapid-acting insulin you need to take every 3, 4 or 6 hours for basal only.  Remember: This insulin is IN ADDITION to insulin needed for carbohydrates and to correct high blood glucose levels.

For example: If you take 30 units of insulin glargine a day – take 30 divided by 24 = 1.25 units per hour. If you want to take your basal doses every 3 hours – then multiply 1.25 X 3 = 3.75 units every 3 hours. If you want to take your basal doses every 4 hours – then multiply 1.25 x 4 = 5 units every 4 hours. **Remember to add this insulin to your doses for carbohydrates and high blood glucose corrections. Add all doses together before rounding off.

If forgetting the insulin glargine injection continues to be a problem – encourage your daughter to consider an insulin pump. With an insulin pump – your insulin is always with you, and you don’t take insulin glargine. So you don’t have to do anything at the same time every day.

Before using the approach described above – discuss the plan with your diabetes care provider. Good luck!

Related Resources:

Children with diabetes

For more information:

Go to the Diabetes health topic.