Chapter IV Insulin and Oral Antidiabetic AgentsINSULIN FACTS Patients with Type I diabetes produce no insulin and must receive insulin by injection. Type II diabetics receive injections if their disease cannot be controlled by diet, exercise, and oral medication. Insulin cannot be taken orally because it is a protein that would be broken down during digestion. Insulin is measured in units. The unit is a measure of weight. 24 units equal 1 mg. U-1000 insulin means that there are 100 units of insulin in 1cc of solution. U-100 syringes are used for measurement Because each patient with diabetes in unique, the development of an insulin therapy schedule is dependent upon several factors including:
Insulin regimes can vary from 1 to 2 injections per day, up to 3 or 4 injections per day. The main goal of insulin therapy is to keep the blood sugar levels as close to normal range as possible. CHARACTERISTICS OF INSULIN It is very important to health care providers and the patient to have a clear understanding of the characteristics of each type of insulin to be taken. When reactions occur, or when blood sugar levels are not well controlled at certain times of the day, knowing the action and characteristics of each insulin taken will help to determine where changes need to be made in the insulin therapy schedule. Characteristics of insulin:
Insulin absorption can be affected by:
In order to maintain consistency in daily insulin absorption and action, sites should be varied within the same anatomical region. The abdominal area provides consistent absorption of insulin, whereas the arms and legs are often affected by exercise. While repeated injections in the same area may delay absorption, massaging the site of injection may cause increased absorption. Lipodystrophy is characterized by either hypertrophy or atrophy of the subcutaneous adipose tissue at the injection site. Rotating injection sites will facilitate absorption of insulin and help prevent scarring at the injection sites. This condition is seldom seen with the use of human insulin and pure pork insulin. PREMIXED INSULIN Premixed insulin works well for patients whose insulin requirements are set and for those who may have difficulty measuring their dosage. Although this type of packaging is convenient, premixed insulin does not allow for flexibility in dosage adjustment. Premixed insulin is a combination of specific proportions of short acting ® and intermediate acting (N) insulin in one bottle or in an insulin pen cartridge. Premixed insulin combinations include: STORAGE OF INSULIN Insulin is stable at room temperature for approximately one month. Pen-filled cartridges are stable for 21 days. Insulin stored in the refrigerator is good until the expiration date. Extreme temperatures such as freezing, heat or sunlight, can damage insulin. Always check insulin for normal appearance. All cloudy insulin should appear uniformly cloudy when mixed by rolling between your hands, not shaken. If floating particles are seen in the insulin solution, or if insulin is adhering to the sides of the bottle, do not use the insulin. Short acting insulin should be clear and colorless. ALLERGIC REACTIONS AND MILD REACTIONS A small, hard red area at the injection site with itching is indicative of a mild allergic reaction. This usually goes away within a day or so. If a more generalized allergy to insulin occurs, hives and itching will develop over other parts of the body. This disappears by itself, but, if itching persists, the physician should be notified. TYPES OF INSULIN Insulin is beef, pork, beef and pork, or human. This refers to the species of the insulin, which can be found on the label of the bottle. Human insulin is genetically engineered from E, coli bacteria Humulin, or from yeast, Novolin. Human insulin accounts for more than 60% of all insulin used today. Regular insulin (pork, beef, beef/pork, human) is fast acting and lasts a short time in the body. It is used in emergencies for treatment of ketoacidosis. It is used before meals to control the post meal rise in blood sugar, and to lower blood sugar quickly when an immediate reaction is needed. Semi-Lente insulin (beef, pork) is short acting, but twice as long as Regular insulin. It can be used to control post-meal rises in blood sugar and may be used with Lente insulin. NPH insulin (beef, pork, beef/pork, or human) contains added protamine for a intermediate-acting effect. NPH insulin provides a basal amount of insulin. Two injections per day are usually ordered. Ultra-Lente insulin (beef, human) contains a lot of added zinc to give it the longest acting effect. Humulin Ultra-Lente has a shorter peak and duration than beef Ultra-Lente. Ultra-Lente insulin provides the steadiest basal amount of insulin. One injection a day is used in combination with Regular insulin before meals. Insulin Lispro has the trade name Humalog. This insulin is man-made and similar to naturally occurring human insulin. The onset is rapid and it has a shorter duration of action than human regular insulin. Humalog should be taken within 15 minutes of eating and is used I combination with longer-acting insulin. 70/30 insulin (human) is a mixture of 70% NPH and 30% Regular insulin. Two injections per day are usually ordered. TABLE 7: GENERAL INSULIN PREPARATIONS TYPE ONSET DURATION PEAK Regular 30 – 60 minutes 2 – 3 hours 4 – 6 hours NPH 2 – 4 hours 4 – 10 hours 14 – 18 hours Semi-Lente 1 – ½ hours 6 – 8 hours 12 – 14 hours Lente 3 – 4 hours 4 – 12 hours 16 – 20 hours Ultra-Lente 6 – 10 hours 12 – 18 hours 20 – 30 hours Lispro minutes 30 minutes 1 – 5 hours 70/30 15 – 30 minutes 2-3 hours, 8-12 hours 18 – 24 hours When mixing two different types of insulin I one syringe, Regular insulin is drawn into the syringe first, then the longer acting insulin. NOVOLIN PEN INJECTOR The pen-shaped device holds pre-filled cartridges of NPH, regular, or 30/70 insulin. The pen is convenient and easy to use. The needle is placed on one end and the dose is dialed into the pen and then injected. This device is ideal for people on intensive insulin therapy or for those who are away from home at mealtime. THE INSULIN PUMP Pump therapy mimics the action of normal beta cells. This pump delivers both basal rate and bolus doses of insulin. The basal rate is preprogrammed into a continuous delivery of 0.1 unit increments of insulin. Bolus doses are programmed before meals and snacks. Unfortunately, insulin doses are based on blood glucose test results, so the patient must test blood glucose levels four to eight times per day. Blood glucose levels are then interpreted and an appropriate insulin dosage is delivered. Pump wearers must be highly motivated and able to operate the pump. They must be willing to test their glucose frequently, and be able to identify a developing problem. Patients must also have access to a health care team familiar with pump therapy. This device uses computer chip technology, a syringe reservoir, and battery power to deliver insulin automatically to the body. The syringe is filled with buffered Regular insulin such as Velosulin or Humulin BR, which is connected to a thin plastic tube called an infusion set. A catheter is connected to the infusion set. The pump is worn 24 hours a day on a belt, in a packet or on a bra. During swimming or bathing, the syringe is removed from the pump or the tubing may be disconnected from the syringe and capped. It is approximately 2 inches by 3 inches by 5/8 inches. Advantages:
Disadvantages:
INSULIN REACTIONS Hypoglycemic symptoms may come on suddenly, and may progress from mild to severe. Prolonged, sever hypoglycemia can result in damage to the brain or heart. The normal blood sugar range is from 60 – 120 mg/dl. During an insulin reaction, the blood sugar can fall below 60 mg/dl, or fall rapidly from a high level to a lower level or fall below the patient’s usual level. Insulin reactions are due to:
An insulin reaction is the body’s response to low blood sugar. When the brain senses too low blood sugar, it signals the release of hormones called catecholamines. Catecholamines produce the effects of pallor, sweating, shaking, a pounding heartbeat, nervousness and irritability. Catecholamines also cause the release of stored glucose in the liver (glycogen), which raises the blood sugar. Symptoms of Mild Hypoglycemia
Treatment for these symptoms includes giving juice or sugar. Symptoms of Serious Hypoglycemia
Treatment includes juice or sugar along with possible additional medical assistance. Symptoms of Severe Hypoglycemia
If these symptoms occur, the patient is to be given glucose gel if conscious, or glycogen, IVP if unconscious. Next: ORAL ANTIDIABETIC AGENTS |