Medically reviewed on July 24, 2018
What is regular insulin?
Insulin is a hormone that works by lowering levels of glucose (sugar) in the blood. Regular insulin is a short-acting insulin that starts to work within 30 minutes after injection, peaks in 2 to 3 hours, and keeps working for up to 8 hours.
Regular insulin may also be used for purposes not listed in this medication guide.
Before taking this medicine
You should not use ReliOn/HumuLIN R if you are allergic to insulin, or if you are having an episode of hypoglycemia (low blood sugar).
Regular insulin is not approved for use by anyone younger than 2 years old. Regular insulin should not be used to treat type 2 diabetes in a child of any age.
Tell your doctor if you have ever had:
liver or kidney disease; or
Follow your doctor's instructions about using insulin if you are pregnant or breast-feeding. Blood sugar control is very important during pregnancy, and your dose needs may be different during each trimester of pregnancy. Your dose needs may also be different while you are breast-feeding.
How should I use regular insulin?
Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.
Regular insulin is injected under the skin. A healthcare provider may teach you how to properly use the medication by yourself. Regular insulin must not be given with an insulin pump. Do not inject regular insulin into a vein or a muscle.
Read and carefully follow any Instructions for Use provided with your medicine. Do not use insulin if you don't understand all instructions for proper use. Ask your doctor or pharmacist if you have questions.
Prepare your injection only when you are ready to give it. Do not use if the medicine looks cloudy, has changed colors, or has particles in it. Call your pharmacist for new medicine.
Your care provider will show you where to on your body to inject insulin. Use a different place each time you give an injection. Do not inject into the same place two times in a row.
After using regular insulin, you should eat a meal within 30 minutes.
Never share a syringe with another person, even if the needle has been changed. Sharing syringes can allow infections or disease to pass from one person to another.
Low blood sugar (hypoglycemia) can happen to everyone who has diabetes. Symptoms include headache, hunger, sweating, irritability, dizziness, nausea, and feeling shaky. To quickly treat low blood sugar, always keep a fast-acting source of sugar with you such as fruit juice, hard candy, crackers, raisins, or non-diet soda.
Your doctor can prescribe a glucagon emergency injection kit to use in case you have severe hypoglycemia and cannot eat or drink. Be sure your family and close friends know how to give you this injection in an emergency.
Also watch for signs of high blood sugar (hyperglycemia) such as increased thirst or urination, blurred vision, headache, and tiredness.
Blood sugar levels can be affected by stress, illness, surgery, exercise, alcohol use, or skipping meals. Ask your doctor before changing your dose or medication schedule.
Insulin is only part of a complete treatment program that may also include diet, exercise, weight control, blood sugar testing, and special medical care. Follow your doctor's instructions very closely.
In case of emergency, wear or carry medical identification to let others know you have diabetes.
Keep this medicine in its original container protected from heat and light. Do not freeze insulin or store it near the cooling element in a refrigerator. Throw away any insulin that has been frozen.
Storing unopened (not in use) regular insulin:
Refrigerate and use until expiration date; or
Store at room temperature and use within 42 days.
Storing opened (in use) regular insulin:
Store at room temperature and use within 42 days.
Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.
What happens if I miss a dose?
Use the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.
Keep insulin on hand at all times. Get your prescription refilled before you run out of medicine completely.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. Insulin overdose can cause life-threatening hypoglycemia. Symptoms include drowsiness, confusion, blurred vision, numbness or tingling in your mouth, trouble speaking, muscle weakness, clumsy or jerky movements, seizure (convulsions), or loss of consciousness.
What should I avoid while using regular insulin?
Do not change the brand of insulin or syringe you are using without first talking to your doctor or pharmacist. Some brands of insulin and syringes are interchangeable, while others are not. Your doctor and/or pharmacist know which brands can be substituted for one another.
Insulin can cause low blood sugar. Avoid driving or operating machinery until you know how ReliOn/HumuLIN R will affect you.
Avoid medication errors by always checking the medicine label before injecting your insulin.
Avoid drinking alcohol. It can interfere with your diabetes treatment.
Regular insulin side effects
Get emergency medical help if you have signs of insulin allergy: redness, swelling, sweating, itchy skin rash over the entire body, trouble breathing, fast heartbeats, feeling like you might pass out, or swelling in your tongue or throat.
Call your doctor at once if you have:
Common side effects may include:
low blood sugar;
swelling in your hands or feet;
weight gain; or
thickening or hollowing of the skin where you injected the medicine.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect regular insulin?
Many other medicines can affect your blood sugar, or increase/decrease the effects of insulin. Some drugs can also cause you to have fewer symptoms of hypoglycemia, making it harder to tell when your blood sugar is low. Tell your doctor about all your current medicines and any medicine you start or stop using. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
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