Glucose readings UP after a month on insulin

by Chris K
(Bucks County, PA)


Written by: Dr. Albana Greca Sejdini, MD, MMedSc

Medically reviewed by: Dr. Ruden Cakoni, MD, Endocrinologist

Last medically reviewed: July 2026



Question: Why Is My Blood Sugar Higher After Starting Insulin?




Question from Chris:


I stopped Byetta because of an upset stomach and headaches. My A1C was 8.2%, so my doctor prescribed Levemir and Apidra. My glucose was 173 mg/dL on the first day, but for almost a month it has not been below 250 mg/dL despite two daily injections, healthy eating and walking 20–45 minutes daily. Why is my glucose going up?





Quick Answer: Blood glucose that remains above 250 mg/dL after starting insulin needs a same-day review with the prescribing clinician. Do not increase, skip or combine insulin doses yourself. The cause may be an insufficient or mismatched treatment plan, incorrect timing or technique, damaged insulin, illness, another medicine, or the loss of Byetta’s glucose-lowering effect.





Check for ketones: If glucose is 250 mg/dL or higher, especially if you are sick or feel unwell, follow your diabetes sick-day plan and check urine or blood ketones if you have been taught how. Moderate or high ketones require urgent medical advice. High ketones, repeated vomiting, abdominal pain, fruity-smelling breath, deep or difficult breathing, confusion, severe drowsiness or dehydration can signal diabetic ketoacidosis and require emergency care.




Insulin Does Not Usually Make Blood Sugar Rise



Levemir is a basal insulin intended to cover glucose between meals and overnight. Apidra is a rapid-acting insulin generally used around meals according to an individualized prescription. The number of daily injections alone does not show whether the regimen is adequate. Dose, timing, meals, correction instructions and the person’s insulin needs all matter.



Stopping exenatide (Byetta) may remove part of the previous glucose-lowering effect. A starting insulin plan may also need supervised titration. However, it is unsafe to assume that the dose is simply “too low,” because raising the wrong insulin can cause delayed or overnight hypoglycemia. Review your fasting, before-meal, after-meal and bedtime pattern with the doctor who prescribed to you.



Why Glucose May Stay Above 250 After Starting Insulin




  • The regimen needs adjustment: basal, mealtime or correction coverage may not match the glucose pattern, meals or current insulin resistance.

  • Timing or administration problem: the wrong insulin, missed dose, incorrect pen setting, failure to prime, leakage or removing the needle too quickly may reduce the delivered dose.

  • Injection-site problem: repeatedly injecting into lumps or hardened areas can make absorption unpredictable. Rotate sites and avoid damaged skin.

  • Insulin damage: insulin exposed to freezing, excessive heat or direct sunlight can lose effectiveness. Check storage, expiry date and how long the pen or vial has been open.

  • Illness or stress: infection, fever, pain, dental problems, poor sleep, dehydration or emotional stress can raise glucose.

  • Other medicines: corticosteroids and some other drugs can increase glucose. Review every prescription, over-the-counter medicine and supplement.

  • Meter or strip problem: unwashed hands, expired strips or improper strip storage can produce misleading readings.



What to Do Today




  1. Contact the doctor who prescribed insulin to you today. Explain that readings have remained above 250 mg/dL for almost a month. Ask for a clear same-day plan and when to seek emergency care.

  2. Do not change the dose independently. Do not stop basal insulin, take extra rapid insulin, stack correction doses, mix products or change timing unless your written plan tells you to do so.

  3. Record a structured glucose profile. Include fasting, before meals, one to two hours after meals and bedtime, together with insulin name, dose, time, food, activity and symptoms.

  4. Review technique with a clinician, diabetes educator or pharmacist. Bring both insulin devices, needles, glucose meter and medicine list.

  5. Check for illness and ketones. Drink water if you are allowed fluids. Do not use exercise to force glucose down when ketones are present or you feel unwell.



The detailed insulin treatment guide explains basal and mealtime insulin, injection sites, storage and safety. For action thresholds, read what to do with blood sugar between 250 and 400 mg/dL.



What Does an A1C of 8.2% Mean?



An A1C of 8.2% corresponds to an estimated average glucose of about 189 mg/dL. It is above the common A1C goal of below 7% for many nonpregnant adults, but the correct goal must be individualized. The old advice that everyone’s A1C must be below 6% is inaccurate and may be unsafe for some people.



Continue balanced meals and suitable activity, but do not blame yourself when lifestyle measures are not enough. Type 2 diabetes often requires treatment adjustments. Herbs are not harmless: they may cause side effects or interact with insulin and cannot correct an insulin-delivery or dosing problem. Discuss every supplement with your clinician or pharmacist.



When to Seek Emergency Help



Go to an emergency department or call local emergency services if glucose remains at 300 mg/dL or higher and is not improving, if ketones are high, or if you develop vomiting, inability to keep fluids down, abdominal pain, fruity breath, rapid or difficult breathing, confusion, severe weakness, dehydration or unusual drowsiness.



Related Questions




Related Resources




References



  1. ADA: Glycemic Goals, Hypoglycemia and Hyperglycemic Crises—2026

  2. CDC: Diabetic Ketoacidosis

  3. CDC: Managing Sick Days

  4. FDA: Insulin Storage and Extreme Temperatures



Medical disclaimer: Educational only—not personal medical advice. Insulin changes require guidance from the prescribing healthcare professional.


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