Common sense on classification and use of insulin preparations

Insulin plays a crucial role in the treatment of diabetes. For patients whose blood sugar is still poorly controlled after oral hypoglycemic drugs, the efficacy of insulin is irreplaceable. Today the pharmacist will introduce to you commonly used insulin preparations.
1. Classification of insulin preparations

There are many varieties of insulin preparations, which can generally be divided into human insulin and insulin analogs.

Human insulin is divided into short-acting insulin (R) and intermediate-acting insulin (N) according to its onset time and half-life. In addition, there are premixed insulins, which are premixed preparations of short-acting and intermediate-acting insulin. Currently, Commonly used clinical insulin 30R or insulin 70/30 and insulin 50R fall into this category.

Insulin analogs are human insulin that has been artificially improved to have faster onset of action and longer duration of action. Currently, the more commonly used ones are rapid-acting insulins, such as insulin aspart, insulin lispro, insulin glulisine, rapid-acting insulin analogs and premixed preparations of intermediate-acting insulin, such as aspart 30, aspart 50, and Humalog 25. There are also long-acting insulin analogues, currently commonly used insulin glargine and insulin detemir, which have a longer acting time.

We have organized Table 1 in order according to the effective action time of insulin and insulin analogs, from ultra-short-acting to long-acting.

2. Commonly used clinical insulin preparations
1. Neutral insulin injection, colorless and clear solution, can be used for subcutaneous injection and intravenous injection. Its initial action time: 0.5-1 hour, maximum action time: 2-4 hours, and duration of action: 5-7 hours. The functions and applications of neutral insulin are the same as those of ordinary insulin. Its solution is closer to the human body's internal environment, is easily absorbed by the body, and has an effective hypoglycemic effect.

2. Short-acting human insulin, also called ordinary insulin or neutral soluble human insulin, is a colorless and clear solution that can be injected subcutaneously, intramuscularly, or intravenously. The packaging forms include special refills, refills, and bottles. This type of insulin has an initial action time of 0.5 hours and a maximum action time of 1-3 hours. It has a quick onset of action and a short action time. It needs to be injected 30 minutes before a meal to control postprandial blood sugar. Short-acting recombinant human insulin mainly includes Novolin R, Humulin R, and Gansulin R, where R means regular.

3. Intermediate-effect human insulin mainly includes low-protamine zinc human insulin and insulin zinc suspension. The white suspension is only used for subcutaneous injection. The packaging methods include special refills, refills, and bottles. The initial action time of this type of insulin: 1.5 hours, the maximum action time: 4 to 12 hours, and the maintenance time of action: 24 hours. Commonly used drugs on the market include Novolin N, Humulin N, and Gansulin N, where N stands for "Neutral".

4. Premixed human insulin refers to mixing short-acting insulin preparations and intermediate-acting insulin preparations in different proportions, and has the functions of short-acting insulin and long-acting insulin at the same time, that is, biphasic low-protamine zinc human insulin. This type of insulin white suspension is only used for subcutaneous injection. The packaging methods include special refills, refills, and bottles; initial action time: 0.5 hours, maximum action time: 2 to 8 hours, and action maintenance time: 24 hours. We often see that insulin with numbers is premixed insulin, and the number indicates the proportion of short-acting insulin, such as Novolin 30R, Humulin 70/30, and Gansulin 30R.

5. Insulin analogs are products that use genetic engineering technology to partially modify the amino acid sequence and structure of human insulin. They generally refer to substances that can simulate normal insulin secretion and are structurally similar to insulin. This type of insulin mainly includes short-acting insulin analogs and long-acting insulin analogs.
Short-acting insulin analogues include insulin aspart injection and insulin lispro injection. This type of insulin is characterized by a quick onset of action (10-15 minutes) and a short action time (1-2 hours). It can exert a hypoglycemic effect in a short period of time and is mainly used to control postprandial blood sugar in diabetic patients.

The main long-acting insulin analogs are insulin detemir (Insulin Glargine) and insulin glargine (Lantus). Insulin detemir is available in two dosage forms: refill and special refill (300IU/3ml/box); insulin glargine is a disposable injection pen (300IU/3m/box). The above two long-acting insulin analogues only support subcutaneous injection and must not be used for intravenous injection; the characteristics of this type of insulin are significantly prolonged half-life, slow and steady release, small changes in plasma concentration, and long-lasting and effective hypoglycemic effect.

By observing the appearance and color of each insulin, we can clearly identify the insulin packaging method (special refill, refill, bottle) and action time (short-acting, medium-acting, long-acting and premixed), which is helpful for diabetic patients Use insulin correctly to reduce the occurrence of adverse events such as hypoglycemia.
3. Common problems when using insulin preparations

In order to facilitate patients to use insulin more rationally and effectively, improve medication compliance, and reduce the occurrence of hypoglycemia, we have summarized common problems during the use of insulin as follows.

Question 1: Many diabetic patients who are using insulin for the first time have this question. How long does it take to eat after injecting insulin?

1. We see that the insulin brand name with "R" is short-acting insulin (Novolin R), and you must eat carbohydrate-containing food within 30 minutes after injection; the product with "N" is medium-acting insulin (Novolin R). Novolin N), usually injected before going to bed or before breakfast, or twice in the morning and evening; those with numbers or numerical ratios are premixed insulin (Novolin 30, Novolin 30R), 15 minutes after Novolin 30 injection You must eat or inject immediately after eating. You must eat within 30 minutes after injecting Novolin 30R. Short-acting or ultra-short-acting insulin is a clear solution, while intermediate-acting and premixed insulin is a milky white suspension, which needs to be thoroughly mixed before use [5]. We can also select the type of insulin by identifying the appearance color of the insulin bottle and pen.

2. "3-2-1" principle: Generally, ultra-short-acting and short-acting insulin are injected three times a day to control blood sugar after three meals; premixed insulin is injected 2-3 times a day, before meals; medium-acting insulin Inject 1-2 times a day, before going to bed or before breakfast, and use it in conjunction with short-acting insulin; long-acting insulin (Lantus) is injected once a day to control basal blood sugar [6].
Question 2: During our outpatient consultations, we often encounter patients who are using insulin for the first time and come to inquire about how to use the insulin pen. Are there any special requirements for the injection site?

1. Use of insulin pen: When using the insulin pen, the patient only needs to adjust the dosage button to the required dosage unit, then insert the needle into the subcutaneous tissue, and press the dosage button to the end to complete the injection. If liquid overflow occurs frequently during use, it is recommended that the patient use his thumb, index finger and middle finger to pinch the skin (especially on the abdomen) before injecting, keep the needle in the skin for about 10 seconds after the injection, and then relax the skin after pulling out the needle. Can reduce liquid spillage.

2. Insulin should be injected subcutaneously, usually in the thigh or abdominal wall. If convenient, it can also be injected subcutaneously in the buttocks or deltoid muscle. Subcutaneous administration through the abdominal wall is more rapidly absorbed than administration through other injection sites. Pinch up the skin to inject to reduce the risk of accidentally giving an intramuscular injection. To prevent lipodystrophy, injection sites should be rotated within the injection area. Remember that medium- and long-acting insulin and premixed insulin should never be used for intravenous injection [7].

Question 3: During our discharge education for inpatients, diabetic patients who use insulin often ask how to store insulin after returning home. Do they need to be stored in the refrigerator?

1. Unopened insulin should be stored in a refrigerator at 2-8°C. It is best to store it in the refrigerator compartment near the refrigerator door. Do not freeze it [8]. In fact, just as it cannot withstand high temperatures, insulin cannot withstand low temperatures. Freezing will denature the insulin and render it ineffective. Even if it is thawed, the insulin cannot be used again. Once the insulin is found to have frozen, it should be discarded immediately and replaced with new insulin.
2. Opened bottles of insulin and insulin refills can be stored at normal room temperature (around 20°C, not exceeding 25-30°C) for 30 days [8]. It is not recommended to store insulin in refrigeration because insulin products are more stable at room temperature and are easier to mix. Repeated temperature changes will affect the effectiveness of insulin.

I hope everyone can learn the correct method of storing and using insulin to achieve the best effect of insulin treatment, effectively control blood sugar, avoid the occurrence of hypoglycemia, and delay the occurrence of various diabetic complications.