Humulin R: Uses, Dosage, Side effects, Interactions and Alternatives

Research Based
Medically reviewed by - Dr Lara Mokhtar, MD Written by - Dr. Shaheen Shah


What is Humulin R?

Humulin R is the trade name for diabetic medication. Doctors prescribe Humulin R for regulating blood sugar levels in people viz; children and adults with type 1 and type 2 diabetes.

Humulin R is available in liquid solution and comes in vials or prefilled injectable pens. One can avail of Humulin R from health stores with or without a prescription. Doctors give Humulin R as an injection under the skin.

Humulin R is the trade name for diabetic medication. Doctors prescribe Humulin R for regulating blood sugar levels in people viz; children and adults with type 1 and type 2 diabetes.

Here are some quick facts about Humulin R

  • Humulin R is not available in its generic form.
  • The American Diabetic Association called Humulin R by names such as human regular insulin, human insulin, and regular insulin 1Overview| Researched based study from

Category of drug

  • Humulin R is a kind of regular insulin that contains insulin human as the active ingredient. It is a biological drug made from living cells.
  • Humulin R is of the drug class called short-acting insulins. It helps maintain the blood sugar level in diabetic individuals for three to six hours 2Overview| Researched based study from

Mode of action

Humulin R is a copy of our body’s natural insulin and works by doing the same function as our body’s insulin, such as:

  • Inhibiting the liver from making excess blood glucose
  • Assist the fat and muscle cells to take up the blood glucose
  • Inhibit the body from breaking fats and proteins, disintegrating blood glucose, and maintaining sugar levels 3Overview| Researched based study from


Uses of Humulin R

  • The Food and Drug Administration, United States has approved Humulin R to treat diabetes viz; type 1 and type 2 diabetes
  • Humulin R takes up natural insulin’s function and controls the blood sugar in the body 2Uses| Researched based study from


Dosage of Humulin R

The doctor recommends dosage for Humulin R based on several factors such as the type of diabetes (type 1 or type 2), medications one already uses, and other health issues.

Initially, the doctor will start with a lower dose, and then over time, he will gradually adjust the amount appropriate for the patient.

Some of the commonly recommended dosages of Humulin R for diabetes are as follows:

Type 1 diabetes

  • Starting dose-0.5 units of Humulin R per kg (kilogram) of body weight per day
  • One has to take the daily dose as two or three injections given half an hour before mealtime.

Type 2 diabetes

  • Starting dose-0.1 to 0.2 units of Humulin R per kg (kilogram) of body weight per day
  • The daily dose is two or three injections; one must take it half an hour before mealtime 4Dosage| Researched based study from

Taking Humulin R

  • Doctors administer Humulin R injections intravenously, i.e., in a vein over time.
  • The doctor will guide the patient on self-administering of Humulin R.
  • Always inject at a new site each time while injecting Humulin R to avoid the risk of injection site reaction.
  • One can inject Humulin R at the upper arm, upper thigh, belly,and buttock.

Missed dose of Humulin R

  • In case of missed doses, take the quantity instantly when you remember.
  • However, never take two injections simultaneously, which can have rigorous side effects such as hypoglycemia, i.e., low blood sugar.
  • One who wants to be sure of taking or skipping the dose must consult the healthcare provider.

Overdose of Humulin R

  • One must take Humulin R as the physician directs, as high doses can lead to serious side effects such as low potassium and sugar levels.
  • However, in case of accidental excessive drug intake, one must dial the emergency medical number based on the geographical site or rush to the nearby emergency medical room 7Dosage| Researched based study from


Formulation of Humulin R

Humulin R, available as a liquid solution, has two strengths (power):

  • Humulin R U-100(Strength-100 units of insulin in 1 milliliter of solution)
  • Humulin R U-500 (Strength-500 units of insulin in 1 milliliter of solution)

Humulin R U-100comes in two vials:

  • 3 mL vial-Strength is 300 units of insulin
  • 10 mL vial-Strength is 1000 units of insulin

Humulin R U-500 comes in:

  • A single 20 mL vial-Strength is 10,000 units of insulin.
  • Humulin R U-500 is also available as a 3 mL prefilled pen (KwikPen) for use by a single person more than once. One has to use new needles to inject each dose with the pen.
  • 3 mL KwikPen-Strength is 1500 units of insulin 6Forms| Researched based study from

Side effects

Side effects of Humulin R.

Side effects of Humulin R

Common side effects

Some common side effects are:

Injection site reaction :

with symptoms like

  • Pain at the injection site
  • Skin reddening
  • Bleeding
  • Thickened skin
  • Skin lumps
  • Itching

Hypoglycemia (low blood sugar)

Symptoms are:

  • Weakness
  • Hunger
  • Headache
  • Confusion
  • Lightheadedness

Mild side effects

  • Weight gain
  • Stomach gas (bloating)
  • Swelling in the legs and arms
  • Proteins build up in the injected site
  • Skin lesions at the injected site

Serious side effects

Serious side effects are:

Allergic reaction

With symptoms like

  • Hives
  • Itching
  • Swelling in the mouth, lips, tongue and throat
  • Swelling of eyelids, hands, and feet
  • Difficult breathing

Low potassium in the blood (Hypokalemia)

Symptoms are

  • Extreme tiredness
  • Abnormal heartbeat
  • Weakness
  • Muscle pain
  • Difficulty in clearing bowels

Severe low blood sugar

Symptoms are

  • Body shaking
  • Fainting
  • Coma (prolonged loss of body consciousness)
  • Death(in extreme cases) 5Side effects| Researched based study from



Humulin R might not be suitable for people with the following health conditions:

  • If allergic to Humulin R or any of the ingredients of the drug
  • With low potassium levels
  • People on diabetic medication such as thiazolidinediones
  • Moreover, one must not use Humulin R during episodes of hypoglycemia (low blood sugar) 8Contraindications| Researched based study from
  • Alcohol might affect the efficiency of Humulin R. So; it is best to avoid alcohol intake while taking Humulin R.
  • There is no issue with taking Humulin R during pregnancy and breastfeeding. However, it is best to consult with the healthcare provider regarding the risk and benefits of taking Humulin R during those times.


Interactions of Humulin R

Humulin R can interact with several medicines.

Some of the drugs that Humulin R can interact with are as follows:

  • Avantia, Actos(diabetic medication)
  • Haloperidol(Antipsychotic drug)
  • Beta-blockers viz; metoprolol ( Antihypertensive drugs)
  • Levothyroxine (Thyroid medication)
  • Isoniazid, sulfonamides(Antibiotics)
  • Niacin (cholesterol-lowering medication)
  • Protease inhibitors (Human immunodeficiency virus (HIV) medication)
  • Fluoxetine (antidepressants)
  • Pentoxifylline (Peripheral artery disease drug) 9Interactions| Researched based study from

However, it has every chance that interactions might occur with other drugs not listed above. So, patients with medical conditions must always notify the physician about it before taking the medication.


Storage of Humulin R

Store Humulin R away from direct sunlight and heat and avoid keeping it in the freezer

Storage of unopened Humulin R

  • Store Humulin R in the refrigerator at 2 to 8 degrees centigrade.
  • One can also store unopened Humulin R at room temperatures below 30 degrees centigrade for around four weeks.

Storage of opened Humulin R

  • Store Humulin RU-100 and Humulin R-U 500 in the refrigerator at temperatures ranging from 2 to 8 degrees centigrades or at room temperature below 30 degrees Celsius. One can use up to 31 days and 40 days, respectively.
  • One can store opened KwikPens at room temperature and use it for up to four weeks. Once opened, avoid refrigerating it 10Storgae| Researched based study from


  • Dispose of unused medicine in a disposal container, viz; sharps container, to prevent accidental overdose or death of animals or pets.
  • Discard the medication whose expiry date has crossed.


Alternatives to Humulin R

Other drugs are also available to treat diabetes, similar to Humulin R. Some may suit better. One opting for alternative insulin or medicine must discuss it with the doctor to get the best suit.

Alternative insulins for Type 1 or Type 2 diabetes

  • Novolin R
  • Novolin N
  • Humulin N

Alternative drugs other than insulin for Type 2 diabetes

  • Metformin
  • Januvia
  • Nesina
  • Amaryl
  • Ozempic 11Alternatives| Researched based study from


Key Takeaways

  • Humulin R is an FDA-approved medication for treating type 1 and type 2 diabetes
  • People with a medical condition must inform the doctor before taking Humulin R to avoid unwanted side effects.
  • Humulin R has probable side effects. So, one must follow the specific doses as approved by the physician.
Disclaimer: The user acknowledges that this article's information is being offered for informational purposes only. Every attempt has been made to guarantee that the article is informational and correct. If they have any doubts or questions about their health, we firmly advise our readers to visit a doctor or other healthcare professional.

Related Articles

subscribe drcure
subscribe drcure
Thanks for subscribing
Look out for our email. Follow our social pages