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Is Humulin fast or long-acting insulin?

Medically reviewed by Carmen Pope, BPharm. Last updated on June 8, 2023.

Official answer

  • Humulin is the brand name for four different types of insulin, each with a different speed of effect and length of time they work for.
  • Humulin N is an intermediate-acting insulin that starts to work within 2 to 4 hours and lasts for 12 to 18 hours.
  • Humulin R is a short-acting insulin that starts to work within 30 minutes and lasts for 8 hours.
  • Humulin 50:50 and Humulin 70:30 are combination insulins that contain both short and intermediate acting insulins. They start to work within 10 to 20 minutes and last for up to 24 hours.
  • All types of Humulin insulins have the same side effects and drug interactions.

Humulin is a brand name for insulin that is made by Eli Lilly and Company. Insulin is a hormone that is produced naturally in our bodies. Its main role is to allow cells throughout the body to uptake glucose (sugar) and convert it into a form that can be used by these cells for energy. Without insulin, we cannot survive, and death from diabetes was a common occurrence until insulin was discovered in the early 1900s by Frederick Banting and Charles Best.

There are several different types of Humulin and each one has been made to last for a specific length of time, for example:

  • Humulin R: Short-acting insulin
  • Humulin N: Intermediate-acting insulin
  • Humulin 50/50: A combination of 50% intermediate-acting insulin and 50% short-acting insulin
  • Humulin 70/30: A combination of 70% intermediate-acting insulin and 30% short-acting insulin
  • Humulin L and Humulin U have been discontinued.

Different insulins that work for different lengths of time are needed so that the natural release of insulin by the body in response to food is better replicated.

Humulin R

A short-acting insulin that:

  • Starts to work within 30 minutes after injection
  • Peaks in 2 to 3 hours
  • Keeps working for up to 8 hours.

Humulin N

An intermediate-acting insulin that:

  • Starts to work within 2 to 4 hours after injection
  • Peaks in 4 to 12 hours
  • Keeps working for 12 to 18 hours.

Humulin 50:50 and Humulin 70:30

Combination insulins that are usually administered 30 minutes before a meal and contain:

  • A short-acting insulin
  • An intermediate-acting insulin.

These pre-mixed insulins simplify dosing in people needing insulin because they already have a short-acting and an intermediate-acting insulin in them. They start to work within 10 to 20 minutes after injection, peak in 2 hours, and keep working for up to 24 hours.

Related Questions

What are the side effects of Humulin?

Humulin N and Humulin R have the same side effects because they are both insulins. Side effects of insulin include:

  • Low blood sugar levels
  • Weight gain, usually only when a person first starts using it
  • Changes in eyesight
  • Low potassium levels – may be felt as muscle pain, cramps or weakness or a funny heartbeat
  • Mood changes
  • A rash – usually just where you inject the insulin although some people may develop one over their whole body
  • Lumps or scars where you inject the insulin.

What drugs interact with Humulin?

Humulin N and Humulin R have the same interactions because they are both insulins. Interacting medicines include:

  • antidepressants, such as fluoxetine or escitalopram or monoamine oxidase inhibitors such as isocarboxazid
  • antipsychotics, such as aripiprazole or clozapine
  • clonidine
  • corticosteroids such as dexamethasone
  • diuretics, such as bendroflumethiazide
  • fluoroquinolones such as ciprofloxacin or levofloxacin
  • HIV medicines, such as atazanavir or ritonavir
  • hormones, such as estrogen, progesterone or testosterone
  • lithium
  • octreotide
  • orlistat
  • other antidiabetic agents, such as glyburide, or glipizide
  • pentamidine
  • pentoxifylline
  • propoxyphene
  • pseudoephedrine
  • salicylates, such as aspirin
  • salmeterol
  • some heart medications, such as beta-blockers (eg, atenolol or bisoprolol) ACE inhibitors (enalapril or captopril), ARBs (eg candesartan or losartan)
  • sulfonamide antibiotics
  • turmeric.

Note this list is not all-inclusive and does not include all medications that interact with Humulin.



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