Generic name: insulin human regular (injection route) [ IN-su-lin-HUE-man-REG-yoo-lar ]
Drug class: Insulin
Medically reviewed by Drugs.com. Last updated on Jan 9, 2022.
Commonly used brand name(s)
In the U.S.
- HumuLIN R
- HumuLIN R U-100
- NovoLIN R
Available Dosage Forms:
Therapeutic Class: Antidiabetic
Pharmacologic Class: Insulin, Regular
Uses for Humulin R U-100
Insulin human regular is a short-acting type of insulin. Insulin is one of many hormones that help the body turn the food we eat into energy. This is done by using the glucose (sugar) in the blood as quick energy. Also, insulin helps us store energy that we can use later. When you have diabetes mellitus, your body cannot make enough insulin or does not use insulin properly. This causes you to have too much sugar in your blood. Like other types of insulin, insulin human regular is used to keep your blood sugar level close to normal.
This medicine is available only with your doctor's prescription.
Before using Humulin R U-100
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of Humulin® R in children.
Appropriate studies have not been performed on the relationship of age to the effects of Humulin® R U-500 in the pediatric population. Safety and efficacy have not been established.
Although appropriate studies on the relationship of age to the effects of insulin human regular have not been performed in the geriatric population, geriatric-specific problems are not expected to limit the usefulness of this medicine in the elderly. However, elderly patients are more likely to have hypoglycemia and age-related kidney, liver, or heart problems, which may require caution and an adjustment in the dose in patients receiving this medicine.
Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Congestive heart failure or
- Hypokalemia (low potassium in the blood)—May make these conditions worse.
- Emotional disturbances or
- Infection or any illness or
- Stress—These conditions could change blood sugar levels, and may increase the amount of insulin you need.
- Hypoglycemia (low blood sugar)—Should not be used in patients with this condition. If you have low blood sugar and take insulin, your blood sugar may reach dangerously low levels.
- Kidney disease or
- Liver disease—Use with caution. The effects of insulin human regular may be increased because of the slower removal of the medicine from the body.
Proper use of Humulin R U-100
This section provides information on the proper use of a number of products that contain insulin human regular. It may not be specific to Humulin R U-100. Please read with care.
A nurse or other trained health professional may give you this medicine. You may also be taught how to give your medicine at home. This medicine is given as a shot under your skin.
Always double-check both the concentration (strength) of your insulin and your dose. Concentration and dose are not the same. The dose is how many units of insulin you will use. The concentration tells how many units of insulin are in each milliliter (mL), such as 100 units/mL (U-100), but this does not mean you will use 100 units at a time.
Each package of insulin human regular contains a patient information sheet. Read this sheet carefully before beginning your treatment and each time you refill for any new information, and make sure you understand:
- How to prepare the medicine.
- How to inject the medicine.
- How to dispose of syringes, needles, and injection devices.
It is best to use a different place on the body for each injection (eg, under the skin of your abdomen or stomach, thigh, upper arm). Do not use the exact same spot for each injection. If you have questions about this, contact a member of your health care team.
If you use insulin, be very careful when you measure the dose. This form is more concentrated (has more medicine in the same amount of solution) than the U-100 form of insulin. You will need to use less of the solution for each dose. If you are using the vial form of this medicine, you should use the U-500 insulin syringe to get and inject your dose correctly. You should eat a meal within 30 minutes of injecting .
The insulin solution should look clear and colorless. Do not use insulin human regular if it is cloudy or thickened.
Follow carefully the special meal plan your doctor gave you. This is the most important part of controlling your condition, and is necessary if the medicine is to work properly. Also, exercise regularly and test for sugar in your blood or urine as directed.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For injection dosage form:
- For diabetes mellitus:
- Adults—The dose is based on your blood sugar and must be determined by your doctor.
- Children—Use and dose must be determined by your doctor.
- For diabetes mellitus:
Call your doctor or pharmacist for instructions.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
- KwikPen®: Store in the refrigerator. Do not freeze. You may also store at room temperature in a cool place, away from sunlight and heat, but must use within 28 days.
- Humulin® R Concentrated U-500 vials: Store in the refrigerator. Do not freeze. You may also store at room temperature in a cool place, away from sunlight and heat. Use within 40 days. Do not shake the vial.
- Humulin® R vials: Store in the refrigerator in the original carton. Do not freeze. Do not use the insulin if it has been frozen.
Opened medicine that is currently being used:
- KwikPen®: Store at room temperature in a cool place, away from sunlight and heat. Throw away any unused medicine after 28 days. Do not store in the refrigerator.
- Humulin® R Concentrated U-500 vials: Store in the refrigerator. Do not freeze. You may also store at room temperature in a cool place, away from sunlight and heat. Throw away any unused medicine after 40 days. Do not shake the vial.
- Humulin® R vials: Store in the refrigerator. Do not freeze. If you cannot keep your vial of insulin in the refrigerator, you may store it at room temperature for up to 31 days. Keep the vial as cool as possible and away from heat and light.
Precautions while using Humulin R U-100
Never share insulin needles or syringes with others under any circumstances. It is not safe for one pen to be used for more than one person. Sharing needles can result in transmission of hepatitis viruses, HIV, or other bloodborne illnesses.
Your doctor will want to check your progress at regular visits, especially during the first few weeks you are using this medicine. Blood tests may be needed to check for unwanted effects.
It is very important to follow carefully any instructions from your health care team about:
- Alcohol—Drinking alcohol (including beer and wine) may cause severe low blood sugar. Discuss this with your health care team.
- Other medicines—Do not take other medicines during the time you are using this medicine unless they have been discussed with your doctor. This especially includes nonprescription medicines such as aspirin, and medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems.
- Counseling—Other family members need to learn how to prevent side effects or help with side effects if they occur. Also, patients with diabetes may need special counseling about diabetes medicine dosing changes that might occur because of lifestyle changes, such as changes in exercise and diet. Furthermore, counseling on contraception and pregnancy may be needed because of the problems that can occur in patients with diabetes during pregnancy.
- Travel—Keep a recent prescription and your medical history with you. Be prepared for an emergency as you would normally. Make allowances for changing time zones and keep your meal times as close as possible to your usual meal times.
In case of emergency: There may be a time when you need emergency help for a problem caused by your diabetes. You need to be prepared for these emergencies. It is a good idea to:
- Wear a medical identification (ID) bracelet or neck chain at all times. Also, carry an ID card in your wallet or purse that says that you have diabetes and a list of all of your medicines.
- Keep an extra supply of insulin and syringes with needles or injection devices on hand in case high blood sugar occurs.
- Keep some kind of quick-acting sugar handy to treat low blood sugar.
- Have a glucagon kit and a syringe and needle available in case severe low blood sugar occurs. Check and replace any expired kits regularly.
This medicine may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Tell your doctor right away if you have a rash, itching, swelling of the face, tongue, and throat, trouble breathing, or chest pain after you get the injection.
Using this medicine together with other diabetes medicine (eg, pioglitazone, rosiglitazone, Actos®, Actoplus Met®, Avandia®) may cause serious heart problem or edema (fluid retention). Check with your doctor immediately if you are rapidly gaining weight, having shortness of breath, chest pain or discomfort, extreme tiredness or weakness, trouble breathing, uneven heartbeat, or excessive swelling of the hands, wrist, ankles, or feet.
You may have some skin redness, rash, itching, or swelling at the injection site. If this irritation is severe or does not go away, call your doctor. Do not inject this medicine into a skin area that is red, swollen, or itchy.
This medicine may make you dizzy or drowsy. Make sure you know how you react to this medicine before you drive, use machines, or do other jobs that require you to be alert.
Too much insulin human regular can cause hypoglycemia (low blood sugar). Low blood sugar also can occur if you use insulin human regular with another antidiabetic medicine, changes in insulin regimen (eg, insulin strength, type of insulin, injection site), delay or miss a meal or snack, exercise more than usual, or drink alcohol. Symptoms of low blood sugar must be treated before they lead to unconsciousness (passing out). Different people may feel different symptoms of low blood sugar. It is important that you learn which symptoms of low blood sugar you usually have so that you can treat it quickly.
Symptoms of low blood sugar include anxiety, behavior change similar to being drunk, blurred vision, cold sweats, confusion, difficulty in thinking, dizziness or lightheadedness, drowsiness, excessive hunger, fast heartbeat, headache, irritability or abnormal behavior, nervousness, nightmares, restless sleep, shakiness, slurred speech, and tingling in the hands, feet, lips, or tongue.
If symptoms of low blood sugar occur, eat glucose tablets or gel, corn syrup, honey, or sugar cubes, or drink fruit juice, non diet soft drink, or sugar dissolved in water to relieve the symptoms. Also, check your blood for low blood sugar. Get to a doctor or a hospital right away if the symptoms do not improve. Someone should call for emergency help immediately if severe symptoms such as convulsions (seizures) or unconsciousness occur. Have a glucagon kit available, along with a syringe and needle, and know how to use it. Members of your household also should know how to use it.
Hyperglycemia (high blood sugar) may occur if you do not take enough or skip a dose of your medicine, overeat or do not follow your meal plan, changes in insulin regimen, have a fever or infection, or do not exercise as much as usual. High blood sugar can be very serious and must be treated right away. It is important that you learn which symptoms you have in order to treat it quickly. Talk to your doctor about the best way to treat high blood sugar.
Symptoms of high blood sugar include blurred vision, drowsiness, dry mouth, flushed, dry skin, fruit-like breath odor, increased urination, ketones in the urine, loss of appetite, stomachache, nausea, or vomiting, tiredness, troubled breathing (rapid and deep), unconsciousness, and unusual thirst.
If symptoms of high blood sugar occur, check your blood sugar level and then call your doctor for instructions.
This medicine may cause low levels of potassium in your blood. Do not use medicines, supplements, or salt substitutes that contain potassium unless you have discussed this with your doctor.
Humulin R U-100 side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Incidence not known
- blurred vision
- cold sweats
- cool, pale skin
- decreased urine
- difficulty with swallowing
- dry mouth
- fast heartbeat
- flushing or redness of the skin
- hives, itching, or rash
- increased hunger
- increased thirst
- irregular heartbeat
- loss of appetite
- muscle pain or cramps
- numbness or tingling in the hands, feet, or lips
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- slurred speech
- tightness in the chest
- unusual tiredness or weakness
- unusually warm skin
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Incidence not known
- Bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
- redistribution or accumulation of body fat
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Frequently asked questions
- What is the difference between regular insulin and lispro (Humalog)?
- Can Trulicity be used with insulin?
- How and where should I inject insulin?
- How long can Humulin be unrefrigerated?
- How long does Humulin last?
- Is Humulin fast or long-acting insulin?
- Can regular and lispro insulin (Humalog) be mixed?
More about insulin regular
- Drug Information
- Insulin regular
- Insulin regular, concentrated U-500
- Insulin human regular Injection (Advanced Reading)
- Insulin Regular (U-100) Cartridges & Prefilled Pens
- Other brands
- Humulin R, Novolin R, Humulin R U-500 KwikPen, Humulin R U-500 (Concentrated), Myxredlin
Related treatment guides
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.