Compared with oral hypoglycemic drugs, the superiority of insulin is obvious. Firstly, insulin’s hypoglycemic effect is sure and long-lasting, and there is no problem of drug failure that often occurs with oral hypoglycemic drugs; secondly, insulin has no toxic side effects on liver and kidney, and more importantly, early application of insulin is good for protecting and improving the function of pancreatic islets of patients.
With the popularization of diabetes prevention and treatment knowledge, more and more patients with type 2 diabetes have abandoned their previous prejudices against insulin and actively accepted insulin therapy. However, the selection and use of insulin are very delicate, only to master the selection of insulin to better use it, as the so-called “details determine success or failure”, as a diabetic patient receiving insulin therapy must have knowledge of this area.
I. How to store insulin
Unopened insulin should be kept under refrigeration at 2~8℃, and insulin should not be frozen, exposed to the sun and shaken for a long time. Insulin can be stored at room temperature (about 25℃) for about 1 month. Insulin pen (with insulin refill inside) should not be put back into the refrigerator after each injection, because if the injection pen is repeatedly put in and taken out from the refrigerator, if the needle is not taken off, the insulin solution will form air bubbles by heat expansion and cold contraction, resulting in inaccurate injection volume.
Second, how to determine whether insulin is not effective
Patients should check the appearance of the insulin solution before each injection. Under normal circumstances, rapid-acting and short-acting insulin are colorless and clarified solutions, once cloudy or the liquid turns yellow, it cannot be used; medium- and long-acting insulin or premixed insulin are generally in a uniform mist, once lumpy precipitates appear and cannot be shaken well, it cannot be used. In addition, insulin that has passed its shelf life should not be used.
What is the difference between human insulin and animal insulin?
According to the origin of the species, it can be divided into genetically synthesized human insulin and animal insulin. In addition, the potency of animal insulin is lower than that of human insulin, and when animal insulin is replaced by human insulin, the dose needs to be reduced by 15% to 20% accordingly.
IV. What is the difference between insulin and insulin analogues
Insulin analogues are synthetic protein hormones whose chemical structure is slightly different from insulin, but which can combine with insulin receptors to exert hypoglycemic effects. According to their pharmacokinetic characteristics, they are divided into fast-acting insulin analogues (e.g. Novalax, Unisulin) and long-acting insulin analogues (e.g. glargine insulin, trade name “Lexapro”).
Compared with short-acting insulins, rapid-acting insulin analogues have a faster onset of action (15 minutes), with peak effect occurring 1 to 3 hours after injection and maintenance of effect for about 4 hours, which can better mimic physiological insulin secretion after meals and have a better effect on postprandial hyperglycemia control and are less likely to cause hypoglycemia. Since it can be injected immediately before meals, unlike short-acting insulin, which needs to be injected half an hour in advance, patients’ compliance with treatment is better.
Long-acting insulin analogues are mainly used to supplement basal insulin, and compared with medium- and long-acting insulins currently in clinical use, their efficacy is smoother, with no obvious peak effect and less risk of hypoglycemia, and one subcutaneous injection per day can provide 24 hours of basal insulin secretion.
V. How to identify the logo on the insulin bottle
Commercially available insulins come in a variety of dosage forms and specifications, so it is important to distinguish them clearly before use and place them in the right place. The common logos are: RI (abbreviated R) for short-acting insulin; NPH (abbreviated N) for intermediate-acting insulin; PZI for long-acting insulin; 30R (or 70/30) for premixed insulin consisting of 30% short-acting insulin and 70% intermediate-acting insulin; 50R (or 50/50) for premixed insulin consisting of 50% short-acting insulin and 50% intermediate-acting insulin. u-40 indicates that the concentration of insulin is 40U/ml; U-100 indicates that the concentration of insulin is 100U/ml.
VI. Characteristics of the action of different insulin dosage forms
Clinically, insulin is divided into short-acting, medium-acting and long-acting preparations according to the speed of onset of action and the duration of action. Short-acting insulin takes effect half an hour after subcutaneous injection, with the peak effect occurring 1 to 3 hours after injection and the duration of action being 5 to 7 hours, mainly used to control hyperglycemia after a meal; medium-acting insulin takes effect 1.5 hours after subcutaneous injection, with the peak effect occurring 6 to 10 hours after injection and the duration of action being 18 to 24 hours, mainly used to supplement basal insulin and control basal blood sugar in fasting state; long-acting insulin takes effect 1.5 hours after subcutaneous injection, with the peak effect occurring 6 to 10 hours after injection and the duration of action being 18 to 24 hours. It is mainly used to supplement basal insulin and control basal blood sugar in fasting state; long-acting insulin takes effect 3-4 hours after subcutaneous injection, the peak effect occurs 10-16 hours after injection, and the duration of effect is 28-36 hours, it is also mainly used to supplement basal insulin, clinically it is usually used after mixing long-acting insulin with short-acting insulin in certain proportion.
Premixed insulin is a mixture of short-acting insulin and intermediate-acting insulin in different proportions, which takes effect half an hour after subcutaneous injection, with the peak effect occurring in 2-8 hours and the effect maintained for 24 hours, and can be used to control basal and postprandial blood glucose. The newly introduced ultra-short-acting human insulin analogues (such as NovoRel and Unilog) take effect about one quarter of an hour after subcutaneous injection, with the peak effect occurring in 30-60 minutes and the duration of effect lasting 3-4 hours.
Long-acting human insulin analogue (glargine insulin, trade name “Lethal”) is characterized by stable absorption, no obvious peak, long-lasting effect, and can well simulate the secretion of physiological basal insulin, and the effect can be maintained for 24 hours with only one daily injection.
Note: Medium-acting insulin, long-acting insulin and long-acting insulin analogues cannot be used for intravenous injection, and cannot be used for the rescue of acute complications of diabetes (such as coma of ketoacidosis).
Seven, how to prepare and inject insulin by yourself
When mixing short-acting insulin with medium- and long-acting insulin, the short-acting preparation should be taken first, followed by the long-acting or medium-acting preparation, and the order should not be reversed. Medium- and long-acting and premixed insulins should be shaken well before injection, and the injection site should be changed each time, with the interval between the two injection positions being at least 2 cm. Remember to reverse the pen up and down more than 10 times before each injection and shake the pen fully until a uniform white suspension is produced to prevent poor blood glucose control due to concentration errors. Strictly observe the exclusive use of the pen to prevent cross infection and disease transmission.
VIII. How to determine the time interval between insulin injection and meal
The schedule of injection depends on the type of insulin used by the patient and the blood glucose level before meals. In principle, fast-acting insulin analogues have a faster time to function and can be injected immediately before meals; short-acting insulins play a hypoglycemic effect only half an hour after injection and should be injected half an hour before meals. Long-acting basal insulin – “Lethal”, the action time can be maintained for 24 hours, only need to be injected once a day, and there is no peak, can be injected at any time of the day (as long as the daily injection time is fixed).
When the blood sugar is above the target range, the interval between premeal injections can be extended; when the premeal blood sugar is below the target range, the premeal injection should be shortened. For example, if the blood sugar is low before meal, short-acting insulin should be injected immediately before meal.
Who needs insulin therapy
In addition to type 1 diabetes, patients with type 2 diabetes should also switch to insulin therapy if they have the following conditions.
(1) Failure of oral hypoglycemic agents (including primary and secondary failure).
(2) Complicated hepatic or renal insufficiency.
(3) Gestational diabetes or diabetes combined with pregnancy.
(4) Significant wasting.
(5) Acute complications of diabetes mellitus such as ketoacidosis.
(6) Stressful conditions (e.g., severe trauma, major surgery, serious infection, etc.).
New research has confirmed that for the first diagnosis of diabetes mellitus with high blood glucose, short-term (about 2 weeks) insulin intensive treatment can be given once diagnosed, which can make the patient’s pancreatic islet function effectively recovered, and no longer need oral hypoglycemic drugs, and the blood glucose can be controlled in the normal range with diet therapy alone.
X. Treatment plan of switching from oral hypoglycemic drugs to insulin
The treatment plan of switching from oral hypoglycemic drugs to insulin therapy is mainly decided according to the patient’s islet function and the characteristics of blood glucose spectrum, and the patient’s compliance with the treatment is also taken into consideration. There are three basic treatment regimens.
The first regimen: the treatment regimen of short-acting insulin injections before three meals. This program is applicable to the early stage of diabetes mellitus, in which the patients’ basal insulin secretion is still acceptable, and the main manifestation is insufficient insulin secretion after meals (i.e. insufficient islet storage function), therefore, fasting blood glucose is roughly normal and postprandial blood glucose is obviously increased.
The second regimen: the combined treatment regimen of oral hypoglycemic drugs and insulin, i.e. oral hypoglycemic drugs during daytime and subcutaneous injection of medium-acting insulin before bedtime. The advantage of this program is that it can effectively overcome the “dawn phenomenon”, so that the whole night, especially fasting blood glucose, can be well controlled, and thus the effect of oral hypoglycemic drugs during the day can be strengthened, thus ensuring good control of blood glucose throughout the day.
The third program: insulin replacement therapy program, that is, stop using all insulin promoters and mainly rely on insulin to control blood sugar throughout the day. Commonly used regimens include: premixed insulin injections before breakfast and dinner respectively; short-acting insulin injections before three meals, and medium-acting insulin injections at bedtime (or before breakfast and dinner). The alternative treatment program is mainly applied to diabetic patients with complete islet failure and failure of oral hypoglycemic drugs.
XI. How to determine the initial dose of insulin therapy
There are various methods to determine the initial dose of insulin, listed as follows.
1.Patients who take a combined treatment program, the starting dose of medium-acting insulin at bedtime can be calculated at 0.1 to 0.2 units per kilogram of body weight.
2. In patients taking alternative treatment regimens, the starting insulin dose can be estimated in a variety of ways.
(1) Estimation by body weight: Type 2 diabetic patients can calculate the total amount of insulin for the whole day according to 0.2 to 0.8 units/kg body weight (average 0.4 units), and then inject it subcutaneously before three meals according to the distribution principle of morning>evening>medium.
(2) Calculate insulin dosage according to blood glucose value: total insulin for the whole day = 0.003 × [blood glucose (mg/dL) – 100] × body weight (kg).
(3) Decide the insulin dosage according to the “+” of urine glucose, generally one “+” of urine glucose, one injection of 3 to 4 units of insulin.
(4) Estimation is based on the amount of oral hypoglycemic drugs, generally based on the standard of sulfonylurea hypoglycemic drugs (such as euglycemia), one tablet is equivalent to 5 units of insulin, if the patient takes 6 tablets of euglycemia a day, the insulin dosage for the whole day is about 30 units.
Twelve, how to adjust the therapeutic dose of insulin
Generally speaking, the initial use of insulin should start with a small dose (the initial amount should not exceed 30 units/day at most), and then adjust the blood glucose level with reference to fasting, two hours after three meals, before going to bed and at 3:00 a.m. every 3 to 5 days, with a daily adjustment range of 2 to 8 U, until the blood glucose reaches satisfactory control. Do not adjust too fast or too large to prevent serious hypoglycemia or large fluctuations in blood sugar.
XIII. How to choose the insulin dosage form
Insulin is divided into short-acting, medium-acting and long-acting forms according to the speed of onset and duration of action, which are very important in the specific selection.
Short-acting insulin is characterized by fast absorption and short duration, which can control blood glucose within a short period of time and facilitate dose adjustment, and should be selected in the following cases.
(1) The initial treatment phase of insulin, which is convenient for figuring out the dose.
(2) Resuscitation of diabetic ketoacidosis and hyperosmolar coma.
(3) Stressful conditions such as severe infection, surgery, etc.
(4) Elimination of postprandial hyperglycemia.
(5) Intensive treatment with medium- and long-acting insulin.
Intermediate-acting insulin is mainly used to supplement the insufficient secretion of basal insulin, because its onset and duration of effect are between short-acting and long-acting. It is often used as: (1) combination therapy: oral hypoglycemic drugs during daytime and medium-acting insulin injection before bedtime; (2) replacement therapy: subcutaneous injection of medium-acting insulin before breakfast and dinner or injection of short-acting insulin before three meals and medium-acting insulin before bedtime.
Long-acting insulin has a slow onset of action and a longer duration of effect, and is mainly used to supplement the insufficient secretion of basal insulin and reduce nighttime or fasting blood glucose. It is generally not used alone, but often used in combination with short-acting insulin to implement intensive treatment.
XIV. Pay attention to the mutual cooperation of diet, exercise and insulin therapy
Diet and exercise have great influence on blood glucose changes, therefore, during insulin therapy, patients are required to keep fixed meals, meal times, diet and exercise as much as possible. In addition, learn to use the effect of diet and exercise on blood glucose to regulate and stabilize blood glucose, without necessarily changing the insulin treatment dose. For example, if you inject R-type insulin before breakfast and find that the blood sugar is high 2 hours after breakfast and low before lunch, you do not need to change the dose of insulin injected before breakfast, and put 1/3 of the breakfast in one and a half hours after breakfast to add a meal, which not only reduces the blood sugar 2 hours after breakfast, but also avoids low blood sugar before lunch. Of course, postprandial hyperglycemia can also be improved by increasing the amount of exercise.
Fifteen, insulin treatment should be individualized
Insulin treatment should follow the principle of individualized medication, which means that different treatment plans and control goals should be formulated according to each patient’s disease type, condition, age, fat and thin, liver and kidney function status, work and rest pattern, economic conditions and other different situations.
16. Self-monitoring of blood glucose should be strengthened during treatment
Patients and their family members should master the self-monitoring techniques of blood glucose and urine glucose, and frequently perform self-monitoring of blood glucose in order to adjust the dose of insulin in time. The insulin dosage when the patient’s hyperglycemia is corrected is not equal to the maintenance amount required in the future, because after a period of insulin treatment, the function of the pancreatic beta cells of the diabetic patient will be improved to a certain extent after the blood sugar is normalized, and the insulin requirement will be reduced accordingly, which requires timely detection of blood sugar and timely reduction of insulin dosage to avoid the occurrence of hypoglycemia. In addition, when diabetic patients have other diseases (such as cold and fever, diarrhea, etc.), travel and change of life pattern, it is more important to strengthen my blood glucose monitoring and adjust insulin dosage at the right time.
XVII. Insulin therapy should not be interrupted at will
Type 1 diabetes patients should adhere to insulin therapy, except for a few who can suspend insulin during the honeymoon period, in order to protect the residual pancreatic β-cell function and slow down the progress of the disease. type 2 diabetes can only consider switching to oral hypoglycemic drugs if the insulin dosage is less than 20 units throughout the day and still satisfactorily control blood sugar. Note: Do not go to the hospital to prescribe new insulin only when the insulin is used up. You should have a small amount of insulin reserve at home to prevent interruption of treatment due to lack of medication.
18. How to observe and deal with adverse reactions
The main adverse reaction of insulin use is hypoglycemia, which is one of the common acute complications of diabetes and can even be life-threatening in serious cases, therefore, patients and their families should learn to identify it. The symptoms of hypoglycemia are mainly hunger, dizziness, panic, hand tremor, sweating, limpness and weakness, and in serious cases, confusion or even coma, when the measured blood glucose is often lower than 2.8 mmol/L. The causes of hypoglycemia are mainly because the injection dose is too large, not eating in time after the injection or not eating enough, and not adding meals or adjusting the insulin dosage in time due to the high activity. Once hypoglycemia occurs, patients should immediately eat some high sugar diet, such as sugar water, cookies. 10-15 minutes later, if the symptoms have not disappeared, they can eat again. If the symptoms are eliminated but there is still more than one hour before the next meal, you can add a piece of bread or a steamed bun. If you still do not get better after the above treatment, ask your family or friends to help and go to the hospital quickly for examination.
Of course, in addition to observing whether there is hypoglycemia after injection, long-term users should also observe whether there are abnormalities at the injection site, such as subcutaneous hard nodules and atrophy of fatty tissues, etc. However, the human insulin preparations nowadays are of very high purity, and such allergic reactions rarely occur, so patients can have no worries.