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Humulin 70/30 Pen Side Effects

Generic name: insulin isophane / insulin regular

Medically reviewed by Last updated on Apr 12, 2023.

Note: This document contains side effect information about insulin isophane / insulin regular. Some dosage forms listed on this page may not apply to the brand name Humulin 70/30 Pen.

Applies to insulin isophane / insulin regular: subcutaneous suspension.

Serious side effects of Humulin 70/30 Pen

Along with its needed effects, insulin isophane/insulin regular 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 isophane/insulin regular:

Incidence not known

  • Anxiety
  • bloating or swelling of the face, arms, hands, lower legs, or feet
  • blurred vision
  • chest tightness
  • chills
  • cold sweats
  • coma
  • confusion
  • cool, pale skin
  • cough
  • decreased urine
  • depression
  • difficulty swallowing
  • dizziness
  • dry mouth
  • fast heartbeat
  • headache
  • hives, itching, or rash
  • increased hunger
  • increased thirst
  • irregular heartbeat
  • loss of appetite
  • mood changes
  • muscle pain or cramps
  • nausea or vomiting
  • nightmares
  • numbness or tingling in the hands, feet, or lips
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • rapid weight gain
  • seizures
  • shakiness
  • slurred speech
  • tingling of the hands or feet
  • unusual tiredness or weakness
  • unusual weight gain or loss

Other side effects of Humulin 70/30 Pen

Some side effects of insulin isophane / 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

  • Weight gain
  • redness, swelling, or itching at the injection site

For Healthcare Professionals

Applies to insulin isophane / insulin regular: subcutaneous suspension.


Adverse reactions observed with insulin therapy include hypoglycemia, allergic reactions, local injection site reactions, lipodystrophy, rash, pruritus, weight gain, and edema.[Ref]


Uncommon (0.1% to 1%): Local reactions such as redness, swelling, or itching at the injection site

Very rare (less than 0.01%): Systemic reactions[Ref]

Hypersensitivity side effects have included both local and systemic reactions. Local reactions have presented as erythema, swelling, heat, or subcutaneous nodules. They usually occurred within the first two weeks of therapy and then disappear. Systemic allergy is a generalized allergy to insulin which may present as a rash over the whole body, shortness of breath, wheezing, drop in blood pressure, fast pulse, or sweating. Severe cases may be life-threatening.

There have been rare reports of patients with hypersensitivity reactions to human insulins who have tolerated insulins of animal origin.[Ref]


Insulin may cause sodium retention and edema, especially if previously poor metabolic control is improved by intensified insulin therapy.[Ref]

Frequency not reported: Peripheral edema[Ref]


Uncommon (0.1% to 1%): Lipodystrophy

Frequency not reported: Rash, pruritus[Ref]


Very common (10% or more): Hypoglycemia[Ref]


Refraction anomalies may occur upon initiation of insulin; symptoms are usually transient. Intensification of insulin therapy may be associated with temporary worsening of diabetic retinopathy.[Ref]

Frequency not reported: Refraction anomalies, temporary worsening of diabetic retinopathy[Ref]


Injection site reactions including pain, redness, hives, inflammation, bruising, swelling, and itching, may occur. These reactions are usually transitory and may be related to factors other than insulin, such as irritants in the skin cleansing agent or poor injection technique.[Ref]

Frequency not reported: Injection site reactions[Ref]


Weight gain has been attributed to the anabolic effects of insulin and the decrease in glycosuria.[Ref]

Frequency not reported: Weight gain[Ref]


Frequency not reported: Anti-insulin antibodies[Ref]

Nervous system

Frequency not reported: Acute painful neuropathy[Ref]

Fast improvement in blood glucose has been associated with acute painful neuropathy, which is generally reversible.[Ref]

Frequently asked questions


1. Product Information. Humulin 70/30 (insulin isophane-insulin regular). Lilly, Eli and Company. 2002.

2. Cerner Multum, Inc. Australian Product Information.

3. Cerner Multum, Inc. UK Summary of Product Characteristics.

Further information

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.