Humulin R (insulin human) is a prescription drug that’s used to help manage high blood sugar levels caused by diabetes. Humulin R is given as an injection under the skin.
Doctors prescribe Humulin R for adults and children with either type 1 or type 2 diabetes.
To learn more about diabetes and how Humulin R treats it, see the “What is Humulin R used for?” section.
Humulin R basics
Humulin R comes as a solution inside vials. The higher-strength version of the drug also comes in disposable, prefilled injection pens called KwikPens.
You’ll receive the drug as an injection under your skin. Humulin R can also be given by your doctor as an intravenous (IV) infusion. (This is an injection given into a vein over a period of time.)
Humulin R is a type of regular insulin. It contains the active ingredient insulin human, which is a biologic drug. Biologics are made from parts of living cells. Humulin R isn’t available in a biosimilar form. (Biosimilars are like generic drugs. Unlike generics, which are made for nonbiologic drugs, biosimilars are made for biologic drugs.)
You can get Humulin R from your pharmacy with a prescription. Depending on the strength of Humulin R your doctor prescribes, you may also be able to purchase it over the counter (OTC). (The OTC form doesn’t require a prescription from your doctor.)
Read on to learn about Humulin R’s side effects, uses, and more.
Your doctor will recommend the dosage of Humulin R that’s right for you. The following text discusses commonly used dosages, but always take the dosage your doctor prescribes.
Forms and strengths
Humulin R comes as a solution. You’ll receive it as an injection under your skin. The drug can also be given by your doctor as an intravenous (IV) infusion. (This is an injection given into a vein over a period of time.)
Humulin R is available in two strengths:
- U-100, which contains 100 units of insulin per milliliter (mL)
- U-500, which contains 500 units of insulin per mL
The U-100 strength of Humulin R comes in 3-milliliter (mL) and 10-mL vials. You’ll use insulin syringes to take doses of the drug from vials.
The U-500 strength of Humulin R comes in two forms:
- 20-mL vials that you’ll use with insulin syringes
- 3-mL disposable, prefilled injection pens called a KwikPens
Note: Humulin R U-100 is available over the counter (OTC) as well as by prescription. Humulin R U-500 is available only by prescription.
Recommended dosages
Your doctor will likely instruct you to give yourself Humulin R about 30 minutes before you eat. They will tell you exactly how much to take for each dose.
Your dosage of Humulin R depends on:
- the strength of Humulin R you use
- whether you have type 1 or type 2 diabetes
- other medications you take, including other types of insulin
- other medical conditions you have
Sliding scale dosage
Your doctor may determine your dosage of Humulin R using a sliding scale. This method is commonly used to manage blood sugar levels in people staying at a hospital.
With a sliding scale, your exact dosage of Humulin R may depend on:
- your blood sugar level
- the amount of carbohydrates you eat
When using a sliding scale, your doctor will suggest either a low dose, moderate dose, or high dose of insulin. If you have questions about sliding scales with Humulin R, talk with your doctor.
Questions about Humulin R’s dosage
Here’s a list of answers to common questions related to using Humulin R.
- What if I miss a dose of Humulin R? You’ll typically inject Humulin R 30 minutes before you start eating a meal. If you forget your dose, you can check your blood sugar level to decide whether you need insulin. Then, you can either take your missed dose or wait until you would usually take the next dose. If you aren’t sure whether to take a dose of Humulin R or skip it, talk with your doctor. They can tell you what your blood sugar level should be after you’ve eaten.
- Will I need to use Humulin R long term? It’s possible. Diabetes usually requires long-term treatment, and Humulin R can be used long term. If you and your doctor decide that Humulin R is safe and effective for you, you’ll likely use it long term.
- How long does Humulin R take to work? Humulin R starts to manage your blood sugar level within 30 minutes of being injected.
Find answers to some commonly asked questions about Humulin R.
What’s the peak, duration, and onset time of Humulin R?
Here are the typical peak, duration, and onset times for Humulin R:
- Peak time: Each dose of Humulin R reaches its peak (maximum) effect about 3 hours after it’s injected.
- Duration time: The duration of Humulin R’s effect is about 8 hours. (Duration refers to how long the drug keeps working in your body after it’s been injected.) In other words, each dose of Humulin R keeps working in your body for about 8 hours after you inject it.
- Onset time: The onset of Humulin R is about 30 minutes. This means the drug begins working in your body about 30 minutes after you inject it.
If you have more questions about the peak, duration, and onset of Humulin R, talk with your doctor or pharmacist.
Is Humulin R a short-acting insulin?
Yes, Humulin R is a short-acting insulin. Humulin R is considered short acting because it takes about 30 minutes to start working after it’s injected. So, you’ll give yourself doses of Humulin R about 30 minutes before your meals.
For information about short-acting insulin and other types of insulin, talk with your doctor or pharmacist.
How does Humulin R work?
Humulin R is used in adults and children with either type 1 or type 2 diabetes. It helps manage blood sugar levels.
Diabetes is a condition that causes high blood sugar. Usually, your pancreas releases a hormone called insulin to help lower your blood sugar levels. But with diabetes, your body either can’t use the insulin it makes or doesn’t make enough insulin.
Humulin R is a type of regular insulin. Its mechanism of action (how it works) is to replace or add to your body’s natural insulin.
Humulin R lowers your blood sugar levels by:
- keeping your body from breaking down proteins and fats so that it breaks down blood sugar instead
- preventing your liver from making more blood sugar
- helping your fat cells and muscle cells take up sugar from your blood
To find out more about how Humulin R works, talk with your doctor or pharmacist.
Humulin R and Humulin N are used in adults and children with either type 1 or type 2 diabetes. Both medications contain the active ingredient insulin human. These medications help manage blood sugar levels.
Humulin R is a short-acting insulin, while Humulin N is an intermediate-acting insulin. This means they work over different lengths of time inside your body.
To learn more, see the Humulin R and Humulin N comparison in this Humulin R overview. Also, talk with your doctor about which drug is right for you.
Humulin R and Novolin R are both short-acting insulins. They’re used in adults and children with either type 1 or type 2 diabetes. These medications help manage blood sugar levels.
Both Humulin R and Novolin R contain the active ingredient insulin human.
You can find out more by referring to the Humulin R and Novolin R comparison in this Humulin R overview. Your doctor and pharmacist can give you more information about these medications.
Humulin R and Humalog are used in adults and children with either type 1 or type 2 diabetes. These medications help manage blood sugar levels.
Humulin R contains the active ingredient insulin human, while Humalog contains the active ingredient insulin lispro. Humulin R is a short-acting insulin, while Humalog is a rapid-acting insulin. (Rapid-acting insulins usually work faster than short-acting insulins.)
For more information on how Humulin R and Humalog compare, see the “Humalog vs. Humulin” section of this Humalog overview. You can also let your doctor know if you’d like more information about which drug is best for your condition.
Like most drugs, Humulin R may cause mild or serious side effects. The lists that follow describe some of the more common side effects that Humulin R may cause. These lists don’t include all possible side effects.
Keep in mind that side effects of a drug can depend on:
- your age
- other health conditions you have
- other medications you take
Your doctor or pharmacist can tell you more about the potential side effects of Humulin R. They can also suggest ways to help reduce side effects.
Mild side effects
Here’s a short list of some of the mild side effects that Humulin R can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Humulin R’s prescribing information.
Mild side effects of Humulin R that have been reported include:
- weight gain
- injection site reactions
- swelling in your feet, legs, arms, or hands
For more information about some of these side effects, see the “Side effect focus” section later in this article.
Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.
Serious side effects
Serious side effects from Humulin R can occur, but they aren’t common. If you have serious side effects from Humulin R, call your doctor right away. However, if you think you’re having a medical emergency, you should call 911 or your local emergency number.
Serious side effects of Humulin R that have been reported include:
For more information about some of these side effects, see the “Side effect focus” section next.
Side effect focus
Learn more about some of the side effects Humulin R may cause.
Weight gain
You may gain weight while you’re receiving Humulin R. This was one of the more common side effects in studies of the drug.
You may also gain weight if you have swelling, which is another common side effect of Humulin R. Swelling from Humulin R usually affects your feet, legs, arms, or hands.
What might help
It’s important to tell your doctor if you have weight gain while you’re receiving Humulin R.
They may need to adjust your dosage of Humulin R if your weight changes during treatment. Your doctor can also suggest ways to manage your weight through fitness and nutrition while you’re receiving Humulin R.
Injection site reactions
You may have injection site reactions while you’re using Humulin R. These were common in studies of the drug.
You may have any of the following reactions around areas where you inject Humulin R:
- bruising
- buildup of protein under your skin
- itching
- pain
- rash
- thickened skin or pits in your skin
What might help
It’s important to inject each dose of Humulin R into a new area of the skin. You can inject Humulin R into your abdomen, buttocks, upper arms, or upper thighs. Changing your injection site lowers your risk of these reactions.
If you have any of the reactions listed earlier while you’re using Humulin R, don’t inject the drug into the area until it has healed.
If you continue to have bothersome injection site reactions while using Humulin R, talk with your doctor. They can recommend ways to help lessen this side effect.
Low blood sugar level
You may have low blood sugar levels while you’re using Humulin R. This is the most common side effect of all insulin medications, including Humulin R.
Low blood sugar happens when your blood sugar level drops below a certain healthy level. For most people with diabetes, a normal blood sugar level is above 70 milligrams per deciliter (mg/dL).
With low blood sugar, you may have the following symptoms:
- dizziness
- headache
- skin that is paler than usual
- sweating or shaking
- difficulty concentrating
In severe cases, your blood sugar could be so low that you have seizures. You may also lose consciousness, meaning you’re unable to respond to touch or sound.
What might help
Your doctor will tell you how often you should check your blood sugar level while you’re receiving Humulin R. This can help prevent low blood sugar levels.
If you have low blood sugar, the American Diabetes Association recommends the 15-15 rule: Eat at least 15 grams (g) of fast-acting carbohydrates within 15 minutes of having low blood sugar.
Examples of what to consume for 15 g of fast-acting carbohydrates include:
- glucose liquid, gel, tablets, or powder
- hard candy (read the candy’s label to learn how much contains 15 g of glucose)
- 4 ounces of regular (not diet) soda
- 4 ounces of fruit juice
Tell your doctor if you have a low blood sugar level during Humulin R treatment. They can help you understand what caused it. And they can suggest ways to help you avoid another episode.
If you have severe low blood sugar, your blood sugar level may be so low that you need someone’s help to treat it. Be sure a co-worker, friend, family member, or caregiver knows how to recognize and treat this condition.
Severe low blood sugar is a medical emergency, and it should be treated right away. Call 911 or your local emergency phone number if you have symptoms of this condition.
Allergic reactionSome people may have an allergic reaction to Humulin R.
Symptoms of a mild allergic reaction can include:
- skin rash
- itchiness
- flushing (temporary warmth, redness, or deepening of skin color)
A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, typically in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause you breathing difficulty.
Call your doctor right away if you have an allergic reaction to Humulin R. But if you think you’re having a medical emergency, call 911 or your local emergency number.
Costs of prescription drugs can vary depending on many factors. These factors include what your insurance plan covers and which pharmacy you use.
Humulin R is also available in an over-the-counter (OTC) form that doesn’t require a prescription. The cost of the OTC form may be different from the cost of the prescription form. Talk with your doctor if you’d like to know about using OTC Humulin R.
If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. You can also visit the Humulin R manufacturer’s website to see if they have support options.
Cost information and savings coupons
You can visit Optum Perks to get price estimates of what you’d pay for Humulin R U-500 when using coupons from the site. See the coupon options that follow. (Note: Optum Perks coupons cannot be used with any insurance copays or benefits.)
Your doctor will explain how you (or a caregiver) should inject Humulin R. They’ll also explain how much to use and how often. Be sure to follow your doctor’s instructions.
Receiving Humulin R
Humulin R comes as a solution. You’ll receive it as an injection under your skin. The drug can also be given by your doctor as an intravenous (IV) infusion. (This is an injection given into a vein over a period of time.)
Humulin R comes as a solution inside vials that you’ll use with insulin syringes. Humulin R U-500 also comes in disposable, prefilled injection pens called KwikPens.
Your doctor will show you how to give injections of Humulin R to yourself.
It’s important that you inject each dose of Humulin R in a new area. You can inject the drug into any of the following administration sites:
- abdomen
- buttocks
- upper arms
- upper thighs
Changing (rotating) your injection sites for each dose lowers your risk of having injection site reactions. For details about this side effect, see the “What are Humulin R’s side effects?” section.
Receiving Humulin R with food
You should give yourself Humulin R 30 minutes before eating a meal.
Questions for your doctorYou may have questions about Humulin R and your treatment plan. It’s important to discuss all your concerns with your doctor.
Here are a few tips that might help guide your discussion:
- Before your appointment, write down questions such as:
- How will Humulin R affect my body, mood, or lifestyle?
- Bring someone with you to your appointment if doing so will help you feel more comfortable.
- If you don’t understand something related to your condition or treatment, ask your doctor to explain it to you.
Remember, your doctor and other healthcare professionals are available to help you. And they want you to get the best care possible. So, don’t be afraid to ask questions or offer feedback on your treatment.
If you have diabetes, your doctor may prescribe Humulin R. It’s a prescription drug that’s used in adults and children with either type 1 or type 2 diabetes. It helps manage blood sugar levels.
Diabetes is a condition that causes high blood sugar levels. Blood sugar is the main source of energy for your body’s cells. To help blood sugar get into your body’s cells, your pancreas releases a hormone called insulin.
But with diabetes, your body either can’t use the insulin it makes or doesn’t make enough insulin. Over time, this can cause too much sugar to stay in your blood.
Having a high level of blood sugar over a long period of time can cause serious problems, including kidney disease and heart disease.
Humulin R is a type of regular insulin. It works by replacing or adding to the insulin your body makes naturally.
When considering Humulin R, it’s important to talk with your doctor about your overall health. Also tell them about any medications you take and any medical conditions you have.
These factors and others are described in more detail in the text that follows.
Interactions
Taking medications, vaccines, foods, and other things with a certain drug can affect how the drug works. These effects are called interactions.
Before starting Humulin R, be sure to tell your doctor about all the medications you take. This includes prescription and over-the-counter types. Also describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions Humulin may cause with these items.
Interactions with drugs or supplements
Humulin R can interact with several types of drugs. These drugs include:
- diabetes drugs other than Humulin R, such as the thiazolidinedione drugs rosiglitazone and pioglitazone (Actos)
- acromegaly drugs, such as octreotide (Sandostatin)
- antipsychotic drugs, such as haloperidol
- blood pressure drugs, including:
- angiotensin converting enzyme (ACE) inhibitors, such as benazepril (Lotensin)
- angiotensin II receptor blockers (ARBs), such as valsartan (Diovan)
- beta-blockers, such as metoprolol (Lopressor, Toprol XL)
- diuretics, such as furosemide (Lasix)
- corticosteroid drugs, such as prednisone
- oral contraceptives (birth control pills), such as norethindrone acetate/ethinyl estradiol/ferrous fumarate (Lo Loestrin Fe)
- thyroid disorder drugs, such as levothyroxine (Synthroid)
- certain antibiotics, such as:
- isoniazid
- pentamidine (Nebupent, Pentam)
- sulfonamides, such as sulfamethoxazole/trimethoprim (Bactrim)
- certain cholesterol-lowering drugs, such as:
- fibrates, such as fenofibrate
- niacin
- certain HIV drugs, such as protease inhibitors, including ritonavir (Norvir)
- certain antidepressants, such as:
- fluoxetine (Prozac)
- monoamine oxidase inhibitors (MAOIs), such as phenelzine (Nardil)
- the arrhythmia drug disopyramide (Norpace)
- the peripheral artery disease drug pentoxifylline
- the endometriosis drug danazol
This list does not contain all types of drugs that may interact with Humulin R. Your doctor or pharmacist can tell you more about these interactions and any others that may occur with use of Humulin R.
Warnings
Humulin R may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you start Humulin R. Factors to consider include those in the following list.
- Low blood sugar level: You shouldn’t use Humulin R during an episode of low blood sugar. This is because Humulin R can cause low blood sugar. For details, see the “What are Humulin R’s side effects?” section.
- Low potassium level: Before using Humulin R, tell your doctor if you have a low level of potassium. Humulin R can cause low potassium, which could worsen your condition. Also tell your doctor about all other medications you take. They can advise whether any medications you take may also increase your risk of this side effect.
- Allergic reaction: If you’ve had an allergic reaction to Humulin R or any of its ingredients, you shouldn’t use Humulin R. Ask your doctor what other medications are better options for you.
- Use of thiazolidinediones (TZDs): Before starting Humulin R, tell your doctor if you take diabetes drugs called TZDs. Examples of TZDs include rosiglitazone and pioglitazone (Actos). When used with TZDs, Humulin R can increase your risk of swelling. And this swelling could cause new or worsening heart failure. Your doctor can advise whether it’s safe for you to use Humulin R if you take these medications.
Humulin R and alcohol
Alcohol can affect how well Humulin R works to manage your blood sugar levels. This is because alcohol can change your blood sugar levels. For this reason, it’s best to avoid drinking alcohol while you’re receiving Humulin R.
Keep in mind that some liquid medications, such as liquid Nyquil, contain small amounts of alcohol. If possible, you may want to avoid taking medications that contain alcohol while you’re receiving Humulin R.
Before starting Humulin R, tell your doctor about all medications you’re taking. They can advise if those drugs contain alcohol. If you drink alcohol, talk with your doctor about how much is safe for you to drink during Humulin R treatment.
Pregnancy and breastfeeding
There aren’t any known issues with the safety of receiving Humulin R while pregnant or breastfeeding. The drug is generally considered safe for use during these times.
If you’re pregnant or breastfeeding, talk with your doctor about the benefits and risks of using Humulin R.
You should not use more Humulin R than your doctor prescribes. Using more than this can lead to serious side effects.
Symptoms of overdose
Symptoms caused by an overdose can include:
What to do in case you receive too much Humulin R
Call your doctor if you think you’ve received too much Humulin R. You can also call 800-222-1222 to reach America’s Poison Centers, or use its online resource. However, if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.
If you have diabetes, your doctor may prescribe Humulin R for you.
If you have questions about using this drug, talk with your doctor or pharmacist. Your doctor can tell you about other treatment options for diabetes.
Here are a few articles that you might find helpful.
Some questions to ask your doctor about Humulin R may include:
- How should I store Humulin R while I’m traveling?
- How often should I check my blood sugar level while I’m receiving Humulin R?
- What should I do if I notice thickened skin or pits in my skin after injecting Humulin R?
Q:
Are there certain factors that determine whether I should use Humulin R U-500 instead of Humulin R U-100?
AnonymousA:
Your prescribed dosage of Humulin R will likely determine whether you’ll use Humulin R U-500 or Humulin R U-100.
Humulin R U-500 is five times more concentrated than Humulin R U-100. So, it might be the better option if you need to take a large dose of insulin.
Most people will start by using Humulin R U-100. (This helps to minimize medication errors when you’re measuring out doses of the medication.) Then, they may switch to Humulin R U-500 if needed.
If you’re switching from Humulin R U-100 to Humulin R U-500, be sure to talk with your doctor or pharmacist about it. This way, you’ll understand how to properly measure your insulin doses.
The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.