Get emergency medical help if you have any signs of an allergic reaction to Humulin N: redness or swelling where an injection was given, itchy skin rash over the entire body, trouble breathing, chest tightness, feeling like you might pass out, or swelling in your tongue or throat.
Call your doctor at once if you have:
fluid retention - weight gain, swelling in your hands or feet, feeling short of breath; or
low potassium - leg cramps, constipation, irregular heartbeats, fluttering in your chest, increased thirst or urination, numbness or tingling, muscle weakness or limp feeling.
Common Humulin N side effects may include:
low blood sugar;
weight gain, swelling in your hands or feet;
itching, mild skin rash; or
thickening or hollowing of the skin where you injected the medicine.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 Humulin N side effects (more detail)
Before taking this medicine
You should not use Humulin N if you are allergic to insulin isophane, or if you are having an episode of hypoglycemia (low blood sugar).
Do not give Humulin N to a child without a doctor's advice.
To make sure Humulin N is safe for you, tell your doctor if you have ever had:
liver or kidney disease; or
low levels of potassium in your blood (hypokalemia).
Tell your doctor if you also take pioglitazone or rosiglitazone (sometimes contained in combinations with glimepiride or metformin). Taking certain oral diabetes medicines while you are using insulin may increase your risk of serious heart problems.
Tell your doctor if you are pregnant or breastfeeding.
Follow your doctor's instructions about using Humulin N if you are pregnant or you become pregnant. Controlling diabetes is very important during pregnancy, and having high blood sugar may cause complications in both the mother and the baby.
