Ask The Expert
Monitoring

I can understand your being fearful due to the episode you had experienced, as hypoglycemia is a common fear among people taking insulin. However, I am concerned that you may be taking this to the extreme to be afraid of taking any insulin. As soon as you read this answer, I would urge you to contact both your doctor and your diabetes education team to discuss this further.

Please be aware: Without my knowing more specifics, I am sure you can understand that I can only make some general observations and suggestions.

While there are many reasons for a hypoglycemic episode (decreased food, delayed meal, unanticipated exercise, or incorrect insulin dose), I am guessing you had either a severe episode and/or an episode with no known cause.  Regardless, I will list some issues to consider which will help you analyze the situation and also hopefully decrease your fear. The more you understand about managing your condition, the easier it becomes to handle it. I would also recommend you read all of the related questions I have included at the end of this answer, as each one will elaborate on the points I have made in this answer.

Start With the Basics

• Re-visit your diabetes education team:  While your doctor is naturally the first person you need to contact, realistically it is usually your diabetes educator and dietitian who will be able to spend more time analyzing your situation to help you understand the issues I describe below, and also to perhaps suggest modifications to your regimen.  Some people mistakenly assume they only need to see a diabetes educator when they are first diagnosed, but it is also very important to periodically return for education updates. For example, the following items should be assessed:
• Your meal plan: Perhaps you are eating an inconsistent amount of carbohydrates, which can cause erratic blood glucose readings. Or, you may not be aware of how to adjust your insulin dose based on your food content.
• Your exercise routine:  Do you snack appropriately before and/or after activity and/or do you reduce your insulin before and/or after exercise, depending on your individual circumstances?
• Your injection technique: If you accidentally injected into muscle, your insulin would have worked faster. Or, if you do not rotate your injection sites adequately, it is possible that sometimes you inject in scar tissue and other times you do not, which would cause erratic absorption and erratic effects. In addition, you should not inject into an area that will be heavily exercised right after the injection (e.g. do not inject in your thigh and then vigorously ride a bicycle) as the exercise could increase the absorption of the insulin, resulting in sudden hypoglycemia.
• Your stress level:  While stress usually raises blood glucose, in some situations, it can lower it. Regardless, it is worth assessing whether or not you have been under extra stress or pressure with family or work issues.
• Your knowledge of hypoglycemia:  Are you aware of the various causes of hypoglycemia, symptoms, treatment, and prevention? Do you have hypoglycemia unawareness?
• Possible error:  Since this episode happened only once, it is also possible that you may have made a mistake when drawing up your dose; it is unfortunately more common than you would think possible, that some people will accidentally reverse the order/doses of insulin—for example, instead of giving 16 units of NPH and 4 units of regular (short-acting) insulin, one might accidentally draw up the reverse—16 units of regular insulin and 4 units of NPH. This larger than usual dose of regular insulin could cause a rapid drop in blood glucose.

Your Insulin Regimen and Insulin Types

• Your specific insulin regimen and types of insulin may need to be modified:  You did not specify if you take regular insulin before each meal and NPH at bed, or if you are on a 2-shot regimen of NPH/Regular before breakfast and dinner, or a 3 shot regimen of NPH/Regular in the morning, regular at dinner, and NPH at bed. 
• Regardless, the type of regimen you are on can affect your risk of hypoglycemia. For example:
  • If you take 2 shots a day of NPH/Regular at breakfast and dinner, you are at increased risk of hypoglycemia mid morning, before bed, or middle of the night.
  • While many people take NPH with no problems, others have improved their control with less hypoglycemia and less weight gain on either of the longer-acting insulin analogues, such as Lantus® or Levemir®.  You can read more about this in the related question at right.
  • While many people still use regular insulin (which is a short-acting insulin) with no problems, others now prefer the more rapid-acting insulins such Humalog®, Novolog®, or Apidra®.
    • Regular insulin is supposed to be injected 30 to 60 minutes before the meal, and even if you do that, you still may find that your post meal glucose is too high while your glucose may drop too low several hours later (or during the night), because some people get a prolonged effect from their regular insulin.
    • If you inject regular insulin at home before you dine out, this can increase your risk of hypoglycemia if your dinner is delayed.
    • Rapid-acting insulins have the advantage of being able to be injected closer to mealtime (i.e. approximately 15 minutes before the meal), and generally they improve the post meal glucose without causing hypoglycemia later.
• There are pros and cons to every insulin regimen, so the main point is to re-assess your regimen with your diabetes team. You can read more about short-acting vs. rapid-acting insulin in the related question at right.

Test Your Blood Glucose Frequently

• Testing your blood glucose frequently is essential to be sure you are in good control as well as for peace of mind—that includes before an insulin dose, before and after exercise, before driving a car, before driving, and also during other times depending on your individual needs.
• Some people use a continuous glucose sensor, as these devices may display a warning and sound an alarm before you get too low. 

Conclusion

After digesting all of this information, I hope you can see that although hypoglycemia is an unfortunate possible side effect of insulin, hopefully it will not occur frequently and when it does, it will be a rare and mild episode.  It is understandable that the hypoglycemia frightened you, but it is also very important for you to discuss this right away with your diabetes team, reassess your diabetes management plan, and work closely with your team to find the regimen that works best for you.