- Humulin R®
- Humulin N®
- Humulin 70/30®
- Humulin 50/50®
- Humulin R U-500®
- Novolin R®
- Novolin N®
- Novolin 70/30®
Insulin injection is used to control blood sugar in people who have type 1 diabetes (condition in which the body does not make insulin and therefore cannot control the amount of sugar in the blood) or in people who have type 2 diabetes (condition in which the blood sugar is too high because the body does not produce or use insulin normally) that cannot be controlled with oral medications alone. Insulin injection is in a class of medications called hormones. Insulin injection is used to take the place of insulin that is normally produced by the body. It works by helping move sugar from the blood into other body tissues where it is used for energy. It also stops the liver from producing more sugar. All of the types of insulin that are available work in this way. The types of insulin differ only in how quickly they begin to work and how long they continue to control blood sugar.
Insulin comes as a solution (liquid) and a suspension (liquid with particles that will settle on standing) to be injected subcutaneously (under the skin). Insulin is usually injected several times a day, and more than one type of insulin may be needed. Your doctor will tell you which type(s) of insulin to use, how much insulin to use, and how often to inject insulin. Follow these directions carefully. Do not use more or less insulin or use it more often than prescribed by your doctor.
Insulin controls high blood sugar but does not cure diabetes. Continue to use insulin even if you feel well. Do not stop using insulin without talking to your doctor. Do not switch to another brand or type of insulin or change the dose of any type of insulin you use without talking to your doctor.
Insulin comes in vials, pre-filled disposable dosing devices, and cartridges. The cartridges are designed to be placed in dosing pens. Be sure you know what type of container your insulin comes in and what other supplies, such as needles, syringes, or pens, you will need to inject your medication. Make sure that the name and letter on your insulin are exactly what your doctor prescribed.
If your insulin comes in vials, you will need to use syringes to inject your dose. Be sure that you know whether your insulin is U-100 or U-500 and always use a syringe marked for that type of insulin. Always use the same brand and model of needle and syringe. Ask your doctor or pharmacist if you have questions about the type of syringe you should use. Carefully read the manufacturer's instructions to learn how to draw insulin into a syringe and inject your dose. Ask your doctor or pharmacist if you have questions about how to inject your dose.
If your insulin comes in cartridges, you may need to buy an insulin pen separately. Talk to your doctor or pharmacist about the type of pen you should use. Carefully read the instructions that come with your pen, and ask your doctor or pharmacist to show you how to use it.
If your insulin comes in a disposable dosing device, read the instructions that come with the device carefully. Ask your doctor or pharmacist to show you how to use the device.
Never reuse needles or syringes and never share needles, syringes, cartridges, or pens. If you are using an insulin pen, always remove the needle right after you inject your dose. Throw away needles and syringes in a puncture-resistant container. Ask your doctor or pharmacist how to dispose of the puncture-resistant container.
Your doctor may tell you to mix two types of insulin in the same syringe. Your doctor will tell you exactly how to draw both types of insulin into the syringe. Follow these directions carefully. Always draw the same type of insulin into the syringe first, and always use the same brand of needles. Never mix more than one type of insulin in a syringe unless you are told to do so by your doctor.
Always look at your insulin before you inject. If you are using a regular insulin (Humulin R, Novolin R), the insulin should be as clear, colorless, and fluid as water. Do not use this type of insulin if it appears cloudy, thickened, or colored, or if it has solid particles. If you are using an NPH insulin (Humulin N, Novolin N) or a pre-mixed insulin that contains NPH (Humulin 70/30, Humulin 50/50, Novolin 70/30), the insulin should appear cloudy or milky after you mix it. Do not use these types of insulin if there are clumps in the liquid or if there are solid white particles sticking to the bottom or walls of the bottle. Do not use any type of insulin after the expiration date printed on the bottle has passed.
Some types of insulin must be shaken or rotated to mix before use. Ask your doctor or pharmacist if the type of insulin you are using should be mixed and how you should mix it if necessary.
Talk to your doctor or pharmacist about where on your body you should inject insulin. Insulin is usually injected in the stomach (except for 2 inches [5 centimeters] around the belly button), upper arm, upper leg, or buttocks. Do not inject insulin into muscles, scars, or moles. Use a different site for each injection, at least 1/2 inch (1.25 centimeters) away from the previous injection site but in the same general area (for example, the thigh). Use all available sites in the same general area before switching to a different area (for example, the upper arm).
This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.
Before using insulin,
- tell your doctor and pharmacist if you are allergic to any type of insulin or any other medications.
- tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: alpha blockers such as doxazosin (Cardura), prazosin (Minipress), terazosin (Hytrin), tamsulosin (Flomax), and alfuzosin (Uroxatral); angiotensin-converting enzyme (ACE) inhibitors such as benazepril (Lotensin), captopril (Capoten), enalapril (Vasotec), fosinopril (Monopril), lisinopril (Zestril), moexipril (Univasc), perindopril, (Aceon), quinapril (Accupril), ramipril (Altace), and trandolapril (Mavik); antidepressants; asparaginase (Elspar); beta blockers such as atenolol (Tenormin), carvedilol (Coreg), labetalol (Normodyne), metoprolol (Lopressor, Toprol XL), nadolol (Corgard), pindolol, propranolol (Inderal), sotalol (Betapace, Sorine), and timolol (Blocadren); diazoxide (Proglycem); diuretics ('water pills'); medications for asthma and colds; monoamine oxidase (MAO) inhibitors such as isocarboxazid (Marplan), phenelzine (Nardil), selegiline (Eldepryl, Emsam, Zelapar), and tranylcypromine (Parnate); hormonal contraceptives (birth control pills, patches, rings, injections, or implants); niacin (Niacor, Niaspan, Slo-Niacin); octreotide (Sandostatin);oral medications for diabetes; oral steroids such as dexamethasone (Decadron, Dexone), methylprednisolone (Medrol), and prednisone (Deltasone); quinine; quinidine; salicylate pain relievers such as aspirin; sulfa antibiotics; and thyroid medications. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- tell your doctor if you have or have ever had nerve damage caused by diabetes; or adrenal (a small gland near the kidneys), pituitary (a small gland in the brain), thyroid, liver, or kidney disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while using insulin, call your doctor.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are using insulin.
- ask your doctor what to do if you get sick, experience unusual stress, plan to travel across time zones, or change your exercise and activity level. These changes can affect your blood sugar and the amount of insulin you may need.
Be sure to follow all exercise and dietary recommendations made by your doctor or dietitian. It is important to eat a healthy diet and to eat about the same amounts of the same kinds of foods at about the same times every day. Skipping or delaying meals or changing the amount or kind of food you eat can cause problems with your blood sugar control.
Alcohol may cause a decrease in blood sugar. Ask your doctor about the safe use of alcoholic beverages while you are using insulin.
When you first start using insulin, ask your doctor what to do if you forget to inject a dose at the correct time. Write down these directions so that you can refer to them later.
This medication causes changes in your blood sugar. You should know the symptoms of low and high blood sugar and what to do if you have these symptoms.
You may experience hypoglycemia (low blood sugar) while you are using this medication. Your doctor will tell you what you should do if you develop hypoglycemia. He or she may tell you to check your blood sugar, eat or drink a food or beverage that contains sugar, such as hard candy or fruit juice, or get medical care. Follow these directions carefully if you have any of the following symptoms of hypoglycemia. You should be especially alert to these symptoms if you previously used an animal-source insulin and have switched to a human insulin. Your hypoglycemia symptoms may be different or less noticeable while you are using a human insulin. Symptoms of hypoglycemia include:
- dizziness or lightheadedness
- nervousness or irritability
- sudden changes in behavior or mood
- numbness or tingling around the mouth
- pale skin
- clumsy or jerky movements
If hypoglycemia is not treated, severe symptoms may develop. Be sure that your family, friends, and other people who spend time with you know that if you have any of the following symptoms, they should get medical treatment for you immediately.
- loss of consciousness
Call your doctor immediately if you have any of the following symptoms of hyperglycemia (high blood sugar):
- extreme thirst
- frequent urination
- extreme hunger
- blurred vision
If high blood sugar is not treated, a serious, life-threatening condition called diabetic ketoacidosis could develop. Call your doctor immediately if you have any of the these symptoms:
- dry mouth
- upset stomach and vomiting
- shortness of breath
- breath that smells fruity
- decreased consciousness
Insulin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- redness, swelling, and itching at the injection site
- changes in the feel of your skin, fat build-up, or fat breakdown
Some side effects can be serious. If you experience any of the following symptoms, call your doctor immediately:
- rash and/or itching over the whole body
- shortness of breath
- blurred vision
- fast heartbeat
- difficulty breathing or swallowing
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].
Store unopened vials of insulin, unopened disposable dosing devices and unopened insulin pens in the refrigerator. Do not freeze insulin and do not use insulin that has been frozen. Opened vials of insulin should be stored in the refrigerator but may also be stored at room temperature, in a cool place that is away from heat and direct sunlight. Store opened insulin pens and opened dosing devices at room temperature. Check the manufacturer's information to find out how long you may keep your pen or dosing device after the first use. Throw away any medication that is outdated or no longer needed. Talk to your doctor or pharmacist about the proper disposal of your medication.
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include the hypoglycemia symptoms listed above as well as the following:
- loss of consciousness
Keep all appointments with your doctor and the laboratory. Your blood sugar and glycosylated hemoglobin (HbA1c) should be checked regularly to determine your response to insulin. Your doctor will also tell you how to check your response to insulin by measuring your blood or urine sugar levels at home. Follow these directions carefully.
You should always wear a diabetic identification bracelet to be sure you get proper treatment in an emergency.
Do not let anyone else use your medication. Ask your pharmacist any questions you have about refilling your prescription.
It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.
AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.
Last Reviewed: February 1, 2009.