Humulin R U-500 KwikPen Side Effects
Generic name: insulin regular
Medically reviewed by Drugs.com. Last updated on Feb 18, 2022.
Note: This document contains side effect information about insulin regular. Some of the dosage forms listed on this page may not apply to the brand name Humulin R U-500 KwikPen.
For the Consumer
Applies to insulin regular: solution
Side effects requiring immediate medical attention
Along with its needed effects, insulin regular (the active ingredient contained in Humulin R U-500 KwikPen) 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 while taking insulin regular:
Incidence not known
- blurred vision
- chest tightness
- 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
- unusual tiredness or weakness
- unusually warm skin
Side effects not requiring immediate medical attention
Some side effects of insulin regular 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
For Healthcare Professionals
Applies to insulin regular: injectable solution, intravenous solution, subcutaneous solution
Transitory, reversible ophthalmologic refraction disorder and worsening of diabetic retinopathy has been reported with insulin initiation and glucose control intensification. Over the long-term, improved glycemic control decreases the risk for diabetic neuropathy.[Ref]
Frequency not reported: Transitory, reversible ophthalmologic refraction disorder, worsening diabetic neuropathy[Ref]
Uncommon (0.1% to 1%): Lipodystrophy[Ref]
Long-term use of insulin can cause lipodystrophy at the site of repeated insulin injections. Lipodystrophy includes lipohypertrophy (thickening of adipose tissue) and lipoatrophy (thinning of adipose tissues).[Ref]
Uncommon (0.1% to 1%): Local reactions such as redness, swelling, or itching at the injection site
Very rare (less than 0.01%): Anaphylactic reactions
Hypersensitivity reactions have included both local and systemic reactions. Anaphylaxis has been reported. Local reactions have presented as erythema, local edema, and pruritus at the injection site. Most minor reactions to insulin at the injection site resolve in a few days to a few weeks. In some instances these reactions have been caused by other factors such as irritants in a skin cleansing agent or poor injection technique. Localized reactions have been reported with metacresol, which is an excipient in many insulin products.
Increases in titers of anti-insulin antibodies that react with human insulin have been observed; some data indicates the increase is transient. The clinical significance of these antibodies is unknown; it does not appear to cause deterioration in glycemic control.[Ref]
Frequency not reported: Formation of anti-insulin antibodies[Ref]
Frequency not reported: Sodium retention and edema[Ref]
Insulin may cause sodium retention and edema, especially with intensified insulin therapy. Combination use with thiazolidinediones has resulted in fluid retention which has led to or exacerbated heart failure.[Ref]
Very common (10% or more): Hypoglycemia
Rare (less than 0.1%): Insulin resistance
Postmarketing reports: Weight gain[Ref]
Hypoglycemia is the most common adverse reaction of all insulin therapies. The timing of hypoglycemia generally reflects the time-action profile of the administered insulin, however, the time action profile of any insulin may vary considerably in different individuals or at different times in the same individual depending on dose, site of injection, blood supply, temperature, and physical activity. Other factors such as changes in food intake (timing of meals, amount or type of food) and concomitant medications will also affect the risk of hypoglycemia.
Hypokalemia, which is due to a shift in potassium from the extracellular to the intracellular space, occurs with all insulins. Hypokalemia and hypomagnesemia has been reported, particularly in patients treated for diabetic ketoacidosis (DKA). Insulin increases the intracellular transport of phosphate, which often results in hypophosphatemia during treatment of DKA. In situations in which not enough insulin is available to control blood glucose, hyperglycemia, diabetic ketoacidosis, and hyperosmolar hyperglycemic non-ketotic syndrome may occur.
Weight gain has been reported and has been attributed to the anabolic effects of insulin and the decrease in glucosuria.[Ref]
Common (1% to 10%): Injection site hypertrophy
Frequency not reported: Injection site reactions[Ref]
Injection site reactions including pain, redness, hives, inflammation, bruising, swelling, and itching have occurred. These usually resolve in a few days to a few weeks; rotation of the injection site reduces the risk of these reactions developing.[Ref]
Acute painful peripheral neuropathy has been reported with insulin initiation and glucose control intensification. Over the long-term, improved glycemic control decreases the risk for neuropathy.[Ref]
Frequency not reported: Acute painful peripheral neuropathy[Ref]
Frequency not reported: Weight gain[Ref]
Weight gain can occur with insulin use; it is believed to be due to the anabolic effects of insulin and the decrease in glucosuria.[Ref]
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 Humulin R U-500 KwikPen (insulin regular)
- Drug interactions
- Dosage information
- During pregnancy
- Reviews (3)
- Drug images
- Pricing & coupons
- En español
- Drug class: insulin
Related treatment guides
1. "Product Information. Humulin R (insulin regular)." Lilly, Eli and Company (2002):
2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
3. Cerner Multum, Inc. "Australian Product Information." O 0
4. "Product Information. NovoLIN R (insulin regular)." Novo Nordisk Pharmaceuticals Inc (2015):
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.