Brand names: Insulin, Apidra, Humalog, Humulin, Iletin, Novolin
Insulin is prescribed for diabetes mellitus when diet modifications and oral medications fail to correct the condition. Insulin is a hormone produced by the pancreas, a large gland that lies near the stomach. This hormone is necessary for the body's correct use of food, especially sugar. Insulin apparently works by helping sugar penetrate the cell wall, where it is then utilized by the cell. In people with diabetes, the body either does not make enough insulin, or the insulin that is produced cannot be used properly.
There are actually two forms of diabetes: type 1 (insulin-dependent) and type 2 (non-insulin-dependent). Type 1 usually requires insulin injection for life, while type 2 diabetes can usually be treated by dietary changes and/or oral antidiabetic medications such as chlorpropamide, glipizide, and metformin. Occasionally, type 2 diabetics must take insulin injections on a temporary basis, especially during stressful periods or times of illness.
The various available types of insulin differ in several ways: in the source (animal, human, or genetically engineered), in the time requirements for the insulin to take effect, and in the length of time the insulin remains working.
Regular insulin is manufactured from beef and pork pancreas, begins working within 30 to 60 minutes, and lasts for 6 to 8 hours. Variations of insulin have been developed to satisfy the needs of individual patients. For example, zinc suspension insulin is an intermediate-acting insulin that starts working within 1 to 1-1/2 hours and lasts approximately 24 hours. Insulin combined with zinc and protamine is a longer-acting insulin that takes effect within 4 to 6 hours and lasts up to 36 hours. The time and course of action may vary considerably in different individuals or at different times in the same individual. Genetically engineered insulin works faster and for a shorter length of time than regular human insulin and should be used along with a longer-acting insulin. It is available only by prescription.
Animal-based insulin is a very safe product. However, some components may cause an allergic reaction (see "What side effects may occur?"). Therefore, genetically engineered human insulin has been developed to lessen the chance of an allergic reaction. It is structurally identical to the insulin produced by your body's pancreas. However, some human insulin may be produced in a semi-synthetic process that begins with animal-based ingredients, and may cause an allergic reaction.
Regardless of the type of insulin your doctor has prescribed, you should follow carefully the dietary and exercise guidelines he or she has recommended. Failure to follow these guidelines or to take your insulin as prescribed may result in serious and potentially life-threatening complications such as hypoglycemia (lowered blood sugar levels).
Take your insulin exactly as prescribed, being careful to follow your doctor's dietary and exercise recommendations. Before taking your injection, carefully read and follow the manufacturer's instructions on how to prepare your pre-filled pen or syringe. Clean the injection area with alcohol first; typical areas of injection are the abdomen, thighs, and arms. Insert the needle and push the plunger as far as it will go. Do not rub the injection area. To avoid skin damage, the next injection should be made at least half an inch from the previous site.
Some brands of pre-filled syringes can be kept at room temperature for a week or a month. The vial or cartridge of genetically engineered insulin lispro can be kept unrefrigerated for up to 28 days. Check your product's label. Never use insulin after the expiration date which is printed on the label and carton.
If you're using Humalog with an external insulin pump, do not dilute it with another liquid or mix it with any other insulins.
While side effects from insulin use are rare, allergic reactions or low blood sugar (sometimes called "an insulin reaction") may pose significant health risks. Your doctor should be notified if any of the following occur:
Other side effects are virtually eliminated when the correct dose of insulin is matched with the proper diet and level of physical activity. Low blood sugar may develop in poorly controlled or unstable diabetes. Consuming sugar or a sugar-containing product will usually correct the condition, which can be brought about by taking too much insulin, missing or delaying meals, exercising or working more than usual, an infection or illness, a change in the body's need for insulin, drug interactions, or consuming alcohol.
Contact your physician if these symptoms persist.
Remember, too, the symptoms associated with an under-supply of insulin, which can be brought on by taking too little of it, overeating, or fever and infection.
If you are ill, you should check your urine for ketones (acetone), and notify your doctor if the test is positive. This condition can be life-threatening.
Insulin should be used only to correct diabetic conditions.
Wear personal identification that states clearly that you are diabetic. Carry a sugar-containing product such as hard candy to offset any symptoms of low blood sugar.
Do not change the type of insulin or even the model and brand of syringe or needle you use without your physician's instruction. Failure to use the proper syringe may lead to improper dosage levels of insulin.
If you become ill from any cause, especially with nausea and vomiting or fever, your insulin requirements may change. It is important to eat as normally as possible. If you have trouble eating, drink fruit juices, soda, or clear soups, or eat small amounts of bland foods. Test your urine and/or blood sugar and tell your doctor at once. If you have severe and prolonged vomiting, seek emergency medical care.
If you are taking insulin, you should check your glucose levels with home blood and urine testing devices. If your blood tests consistently show above-normal sugar levels or your urine tests consistently show the presence of sugar, your diabetes is not properly controlled, and you should tell your doctor.
To avoid infection or contamination, use disposable needles and syringes or sterilize your reusable syringe and needle carefully.
Always keep handy an extra supply of insulin as well as a spare syringe and needle.
Follow your physician's dietary guidelines as closely as you can and inform your physician of any medication, either prescription or non-prescription, that you are taking. Specific medications, depending on the amount present, that affect insulin levels or its effectiveness include:ACE inhibitors such as the blood pressure medications benazepril and quinaprilAnabolic steroidsAppetite suppressants such as diethylpropionAspirinBeta-blocking blood pressure medicines such as atenolol and metoprololDiuretics such as furosemide and hydrochlorothiazideEpinephrineEstrogensIsoniazidMajor tranquilizers such as chlorpromazine and thioridazineMAO inhibitors (drugs such as the antidepressants phenelzine and tranylcypromine)NiacinOctreotideOral contraceptivesOral drugs for diabetes such as chlorpropamide and tolbutamidePhenytoinSteroid medications such as prednisoneSulfa antibiotics such as sulfamethoxazoleThyroid medications such as levothyroxine
Use alcohol carefully, since excessive alcohol consumption can cause low blood sugar. Don't drink unless your doctor has approved it.
Insulin is considered safe for pregnant women, but pregnancy may make managing your diabetes more difficult.
Properly controlled diabetes is essential for the health of the mother and the developing baby; therefore, it is extremely important that pregnant women follow closely their physician's dietary and exercise guidelines and prescribing instructions.
Since insulin does not pass into breast milk, it is safe for nursing mothers. It is not known whether genetically engineered insulin lispro appears in breast milk.
Your doctor will specify which insulin to use, how much, when, and how often to inject it. Your dosage may be affected by changes in food, activity, illness, medication, pregnancy, exercise, travel, or your work schedule. Proper control of your diabetes requires close and constant cooperation with your doctor. Failure to use your insulin as prescribed may result in serious and potentially fatal complications.
Some insulins should be clear, and some have a cloudy precipitate. Find out what your insulin should look like and check it carefully before using.
Genetically engineered insulin lispro injection should not be used by children under age 12.
Your doctor should be contacted immediately if these symptoms of severe low blood sugar occur.
Eating sugar or a sugar-based product will often correct the condition. If you suspect an overdose, seek medical attention immediately.