How do you take Isophane (NPH) insulin?

This is injected under the skin (not into a vein), usually once or twice daily. Your doctor will tell you exactly how many units to inject based on your blood sugar levels. Most people inject it in the thigh, belly, or upper arm. Gently roll the vial or pen between your palms before use; do not shake it, and the liquid should look evenly cloudy. Always eat after injecting to prevent your blood sugar from dropping too low.

What are the side effects of Isophane (NPH) insulin?

Low blood sugar (you may feel shaky, sweaty, dizzy, confused, or very hungry), weight gain, swelling or redness at the injection site, mild skin thickening or lumps where you inject frequently

Who should not take Isophane (NPH) insulin?

Do not use if you are allergic to isophane insulin or any of its ingredients. Do not inject when your blood sugar is already low (hypoglycemia). Do not inject into a vein; it is only for injection under the skin. People with liver or kidney problems may need dose adjustments.

Prescription

Intermediate-acting insulin (Antidiabetic)

Isophane insulin

Last reviewed July 2026

Who is this for?

For adults (18+). Standard adult dosing applies: see the How to Take tab for full instructions.

What is this drug?

Isophane insulin (also called NPH insulin) is a man-made version of the insulin your body naturally produces. It is an intermediate-acting insulin, meaning it works slowly over several hours to lower your blood sugar by helping your body's cells absorb sugar from your blood.

How it works

Binds to insulin receptors on muscle, adipose, and hepatic cells, activating intracellular signalling pathways that promote glucose uptake and utilisation while inhibiting hepatic glucose production and lipolysis.

What is it used for?

Diabetes (sugar disease) is used to control high blood sugar in both Type 1 diabetes (where your body makes no insulin) and Type 2 diabetes (where your body does not use insulin well enough)

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Diabetes

Prescription Required

You need a doctor's prescription to buy this drug.

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What to watch out for

Always buy your insulin from a licensed pharmacy with proper cold storage; insulin sold by roadside vendors or kept in the heat may be spoiled and dangerous. Never share your insulin pen or needles with another person, even a family member with diabetes, as this can spread infections. Learn to recognize the signs of low blood sugar (shakiness, sweating, confusion) and always carry a sugary snack or glucose tablet with you.

Common Side Effects

Low blood sugar (you may feel shaky, sweaty, dizzy, confused, or very hungry)
weight gain
swelling or redness at the injection site
mild skin thickening or lumps where you inject frequently

Serious Side Effects

Severe low blood sugar (hypoglycemia) includes signs such as fainting
seizures
or inability to wake up; this is a medical emergency. Severe allergic reaction involves sudden rash all over the body
difficulty breathing
fast heartbeat
or swelling of the face and throat. Seek immediate medical help if any of these occur.

Drug Interactions

Some drugs can lower your blood sugar further when combined with insulin, such as diabetes tablets like glimepiride or metformin, so your doctor needs to adjust doses carefully. Alcohol can dangerously drop your blood sugar, especially if you drink on an empty stomach, so limit alcohol and never drink without eating. Steroids (like prednisolone) and some blood pressure drugs (like propranolol) can affect your blood sugar levels; always tell your doctor about all medicines you are taking.

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Pregnancy & Breastfeeding Warning

Insulin is generally considered safe during pregnancy and breastfeeding, but your doctor must closely monitor and adjust your dose because blood sugar needs change during pregnancy, so never adjust doses on your own.

Who Should NOT Take This

Do not use if you are allergic to isophane insulin or any of its ingredients. Do not inject when your blood sugar is already low (hypoglycemia). Do not inject into a vein; it is only for injection under the skin. People with liver or kidney problems may need dose adjustments.

How to Store

Unopened insulin should be stored in a refrigerator (2°C to 8°C), not in the freezer. In Nigeria's hot weather, never leave insulin in a car, near a window, or in direct sunlight as heat destroys it. Once opened, you can keep it at room temperature (below 25°C–30°C depending on the brand) for up to 4–6 weeks; check the leaflet. Keep away from children and dispose of used needles safely.

For information only: not medical advice. Always talk to a doctor or pharmacist before changing your medication.