Insulin Regular Human

Reviewed on 7/20/2022

What Is Insulin and How Does It Work?

Insulin Regular Human is used with a proper diet and exercise program to control high blood sugar in people with diabetes. Controlling high blood sugar helps prevent kidney damage, blindness, nerve problems, loss of limbs, and sexual function problems. Proper control of diabetes may also lessen your risk of a heart attack or stroke.

This man-made insulin product is the same as human insulin. It replaces the insulin that your body would normally make. It is a short-acting insulin. It works by helping blood sugar (glucose) get into cells so your body can use it for energy.

  • This medication is usually used in combination with a medium- or long-acting insulin product.
  • This medication may also be used alone or with other oral diabetes drugs (such as metformin).

Insulin Regular Human is available under the following different brand names: Humulin R, Novolin R, Humulin R U-500, and Myxredlin

What Are Side Effects Associated with Using Insulin?

Common side effects associated with the use of Insulin, include the following:

Serious side effects of insulin for regular human include:

  • Low blood potassium symptoms (hypokalemia) including muscle cramps, weakness, irregular heartbeat
  • hives, 
  • difficulty breathing, 
  • swelling of the face, lips, tongue, or throat, and
  • redness, 
  • swelling, 
  • sweating, 
  • itchy skin rash over the entire body, 
  • fast heartbeats, 
  • lightheadedness
  • leg cramps, 
  • constipation, 
  • irregular heartbeats, 
  • fluttering in the chest, 
  • increased thirst or urination, 
  • numbness or tingling, and
  • muscle weakness or limp feeling

Seek medical care or call 911 at once if you have the following serious side effects:

  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheartedness, or passing out.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.


Diabetes is defined best as... See Answer

Dosages of Insulin

Adult and pediatric dosage

Injectable solution


  • 100 units/mL (3mL vial)
  • 100 units/mL (10mL vial)


  • 500 units/mL (20mL vial); prescribe with U-500 syringes to avoid conversion for U-100 tuberculin syringe
  • 500 units/mL (3mL pen)
  • 100 units/100 mL 0.9% NaCl (Myxredlin)

Type 1 Diabetes Mellitus

  • Adult dosage
    • Initial: 0.2-0.4 units/kg/day SC divided every 8 hours or more frequently
    • Maintenance: 0.5-1 unit/kg/day SC divided every 8 hours or more frequently; in insulin-resistant patients (eg, due to obesity), substantially higher daily insulin may be required
    • Adolescents: May require up to 1.5 mg/kg/day during puberty
    • The average total daily insulin requirement for prepubertal children varies from 0.7-1 unit/kg/day but may be much lower
  • Insulin pump (continuous SC insulin infusion)/Adult and pediatric dosage
    • Use appropriate rapid-acting insulin formulation consisting of a combination of basal continuous insulin infusion rate with preprogrammed, premeal bolus doses controlled by the patient. 
    • Conversion from multiple daily SC doses of maintenance insulin: consider reducing the basal rate to less than the equivalent of total daily units of longer-acting insulin (eg, NPH); divide the total number of units by 24 to get basal rate in units/hr; total units of regular insulin or other rapid-acting insulin formulations should not be included in this calculation
  • IV Infusion/Adult and pediatric dosage
    • Individualize and adjust dosage based on the individual’s metabolic needs, blood glucose monitoring results, and glycemic control goal
    • Dosage adjustments may be needed with changes in nutrition, changes in renal or hepatic function, or during acute illness

Type 2 Diabetes Mellitus

Adult dosage

  • SC injection
  • The suggested beginning dose of 10 units/day SC (or 0.1-0.2 unit/kg/day) in the evening or divided every 12 hours
  • Morning: 
    • Give two-thirds of the daily insulin requirement
    • The ratio of regular insulin to NPH insulin is 1:2
  • Evening
    • Give one-third of the daily insulin requirement
    • The ratio of regular insulin to NPH insulin is 1:1
  • IV infusion
    • Individualize and adjust dosage based on the individual’s metabolic needs, blood glucose monitoring results, and glycemic control goal
    • Dosage adjustments may be needed with changes in nutrition, changes in renal or hepatic function, or during acute illness 

Pediatric dosage

  • Children younger than 10 years: Safety and efficacy not established
  • Children 10 years or older: 
    • The goal is to achieve hbA1C of less than 6.5% as quickly as possible by titrating the medications
    • Therapy may include once-daily intermediate-acting insulin or basal insulin in combination with lifestyle changes and metformin
    • Initial treatment with prandial insulin (rapid-acting insulin or regular insulin) may be considered in patients failing to achieve glycemic goals with metformin and basal insulin
    • Taper once the initial goal is reached; transition to the lowest effective dose or metformin monotherapy, if possible
  • IV Infusion
    • Individualize and adjust dosage based on the individual’s metabolic needs, blood glucose monitoring results, and glycemic control goal
    • Dosage adjustments may be needed with changes in nutrition, changes in renal or hepatic function, or during acute illness

What Other Drugs Interact with Insulin?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

Severe Interactions of insulin include:

Serious Interactions of insulin include:

Insulin Regular Human has moderate interactions with at least 126 different drugs.

Insulin Regular Human has mild interactions with at least 78 different drugs.

This information does not contain all possible interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist about all the products you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions, concerns, or more information about this medicine.


Diabetes: What Raises and Lowers Your Blood Sugar Level? See Slideshow

What Are Warnings and Precautions for Insulin?


  • This medication contains insulin for a regular human. Do not take Humulin R, Novolin R, or Humulin R U-500 if you are allergic to insulin regular human or any ingredients contained in this drug.
  • Keep out of reach of children. In case of overdose, get medical help or contact a Poison Control Center immediately


  • Hypersensitivity
  • Low blood sugar (hypoglycemia)

Effects of Drug Abuse

  • No information provided

Short-Term Effects

  • See "What Are Side Effects Associated with Using Insulin?"

Long-Term Effects

  • See "What Are Side Effects Associated with Using Insulin?"


  • Never share pens, needles, or syringes between patients
  • Use with caution in patients with decreased insulin requirements: Diarrhea, nausea/vomiting, malabsorptionhypothyroidism, renal impairment, and hepatic impairment
  • Use with caution in patients with increased insulin requirements: Fever, hyperthyroidismtrauma, infection, and surgery
  • Severe, life-threatening, generalized allergy, including anaphylaxis, can occur; discontinue therapy if indicated
  • Not for mixing with any insulin for intravenous use or with insulins other than NPH insulin for subcutaneous use
  • Use caution in pregnancy
  • Hyperglycemia or hypoglycemia with changes in insulin regimen
    • Rapid changes in serum glucose may induce symptoms of hypoglycemia; increase monitoring with changes to insulin dosage, co-administered glucose lowering medications, meal pattern, and physical activity; and in patients with renal impairment or hepatic impairment, or hypoglycemia unawareness
    • Changes in insulin strength, manufacturer, type, or method of administration may affect glycemic control and predispose to hypoglycemia or hyperglycemia; changes should be made cautiously and under close medical supervision, and the frequency of blood glucose monitoring should be increased; for patients with type 2 diabetes, dosage adjustments of concomitant anti-diabetic products may be needed
    • Hypoglycemia is the most common cause of adverse reactions (headache, tachycardia, etc)
    • Severe hypoglycemia can cause seizures, may lead to unconsciousness, may be life-threatening or cause death; can impair concentration ability and reaction time; this may place an individual and others at risk in situations where these abilities are important (e.g. driving or operating other machinery)
    • Hypoglycemia can happen suddenly and symptoms may differ in each and change over time in the same individual; symptomatic awareness may be less pronounced in patients with longstanding diabetes, in patients with diabetic nerve disease, in patients using medications that block the sympathetic nervous system (e.g., beta-blockers), or in patients who experience recurrent hypoglycemia
    • The risk of hypoglycemia after injection is related to the duration of action of insulin and, in general, is highest when the glucose-lowering effect of insulin is maximal; as with all insulin preparations, the glucose-lowering effect time course may vary in different individuals or at different times in the same individual and depends on many conditions, including the area of injection as well as injection site blood supply and temperature
    • Patients and caregivers must be educated to recognize and manage hypoglycemia; self-monitoring of blood glucose plays an essential role in the prevention and management of hypoglycemia; in patients at higher risk for hypoglycemia and patients who have reduced symptomatic awareness of hypoglycemia, increased frequency of blood glucose monitoring recommended
    • Repeated insulin injections into areas of lipodystrophy or localized cutaneous amyloidosis are reported to result in hyperglycemia; a sudden change in the injection site (to an unaffected area) has been reported to result in hypoglycemia
    • Make any changes to a patient’s insulin regimen under close medical supervision with increased frequency of blood glucose monitoring
    • Advise patients who have repeatedly injected into areas of lipodystrophy or localized cutaneous amyloidosis to change injection site to unaffected areas and closely monitor for hypoglycemia
    • For patients with type 2 diabetes, dosage adjustments in concomitant oral antidiabetic treatment may be needed

Medication errors associated with U-500

  • The prescribed dose should always be expressed in actual units of insulin and NOT volume
  • Reports of errors resulting in hyperglycemia, hypoglycemia, or death
  • The majority of errors occurred due to errors in dispensing, prescribing, or administration; confusion with corresponding markings on the syringe the patient is using (ie, a U-100 insulin syringe or tuberculin syringe)
  • To avoid medication errors between insulin types, instruct patients to always check the insulin label before each injection

Drug interactions overview

  • May cause a shift in potassium from extracellular to intracellular space, possibly leading to hypokalemia; caution when coadministered with potassium-lowering drugs or when administered to patients with a condition that may decrease potassium; untreated hypokalemia may cause respiratory paralysisventricular arrhythmia, and death; monitor potassium levels in patients at risk for hypokalemia if indicated
  • Thiazolidinediones are peroxisome proliferator-activated receptor (PPAR)-gamma agonists and can cause dose-related fluid retention, particularly when used in combination with insulin; fluid retention may lead to or exacerbate heart failure; monitor for signs and symptoms of heart failure, treat the patient accordingly, and consider discontinuing thiazolidinediones
  • Coadministration with drugs that may decrease the blood-glucose-lowering effect (eg, atypical antipsychotics): Adjust dose and increase the frequency of monitoring
  • Coadministration with drugs that may decrease or increase the blood-glucose-lowering effect (eg, alcohol): Adjust dose and increase the frequency of monitoring
  • Increased frequency of glucose monitoring when concomitantly insulin regular human with drugs that may blunt signs and symptoms of hypoglycemia (eg, beta-blockers)

Pregnancy and Lactation

  • Available data from published studies over decades have not established an association between human insulin use during pregnancy and major birth defectsmiscarriage, or adverse maternal or fetal outcomes
  • There are risks to mother and fetus associated with poorly controlled diabetes in pregnancy; animal reproduction studies were not performed

Clinical considerations

  • Poorly controlled diabetes in pregnancy increases the maternal risk for diabetic ketoacidosispreeclampsia, spontaneous abortions, preterm delivery, stillbirth, and delivery complications; poorly controlled diabetes increases the fetal risk for major birth defects, stillbirth, and macrosomia-related morbidity
  • Available data from published literature suggests that exogenous human insulin products are transferred into human milk; there are no adverse reactions reported in breastfed infants in the literature; there are no data on the effects of exogenous human insulin products, on milk production
  • Consider developmental and health benefits of breastfeeding along with the mother’s clinical need for therapy, and any potential adverse effects on the breastfed infant from drugs, or underlying maternal condition
Medscape. Insulin, Regular Human.
RxList. Humulin R. Side Effects Center.

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