Humulin M3 100 IU/mL suspension for injection in cartridge – human insulin premix for diabetes

Humulin M3 contains human insulin produced by recombinant DNA technology, with the same structure as the natural pancreatic hormone. It is a ready-made, defined mixture of fast-acting and long-acting insulin: 30% insulin dissolved in water and 70% isophane insulin, whose action is prolonged by the addition of protamine sulphate.

The medicine is used to treat diabetes mellitus in patients who need insulin to maintain normal blood sugar and serves for long-term glucose control. In Serbia it is authorised as a 100 IU/mL suspension for injection in 3 mL cartridges (pack of 5), used only in Lilly reusable pens. It is manufactured by Lilly France and Eli Lilly Italia.

What is Humulin M3 used for and how is it used correctly?

Basic information about the medicine

What is Humulin M3 used for?

Humulin M3 is indicated for the treatment of patients with diabetes mellitus who require insulin to maintain normal glucose homeostasis. Diabetes develops when the pancreas does not produce enough insulin to control blood sugar.

Your doctor may also prescribe a fast-acting insulin with Humulin M3 – each type of insulin has its own leaflet.

How is it used and dosed?

• The dose is decided by the doctor according to the patient’s needs – exactly how much, when and how often; follow these instructions strictly and attend regular check-ups.
• The medicine is injected only under the skin (subcutaneously) with a reusable Lilly pen; it must not be given into a vein. The 3 mL cartridge is used only in a 3 mL pen.
• Injection sites are the upper arm, thigh, buttock or abdomen; sites are rotated so that the same site is not used more often than about once a month, and each injection is given at least 1 cm from the previous one.
• Immediately before use, roll the cartridge between your palms 10 times and turn it up and down 10 times until the contents are evenly cloudy or milky white; do not shake vigorously. Do not use it if there are clumps or solid white particles stuck to the cartridge walls.
• Before each injection prime the pen with 1–2 units until a drop of insulin appears; after injecting, leave the needle in the skin for 5 seconds and do not rub the site. Remove the needle immediately after the injection.
• No other insulin may be mixed into a Humulin M3 cartridge.
• When switching from another type of insulin (e.g. of animal origin), the dose may be higher or lower and may change over several weeks or months.

These are the general instructions from the leaflet – your doctor decides your dose and injection schedule.

Special patient groups

• Children and adolescents: there are no specific data for Humulin M3; according to the SmPC, published data indicate that human insulin can be used in children and adolescents – the doctor decides on use.
• Kidney or liver impairment: insulin requirements may change; worsening kidney or liver disease increases the risk of hypoglycaemia – tell your doctor.
• Illness, increased physical activity and alcohol: may change the insulin dose needed.

Contraindications – when the medicine must not be used

• when you think hypoglycaemia (low blood sugar) is starting
• allergy (hypersensitivity) to human insulin or any of the excipients

Precautions and warnings

• If your insulin treatment controls your blood sugar well, warning signs of falling blood sugar may be weaker – so plan meals and physical activity carefully and measure your blood sugar often.
• Some patients who switched from animal to human insulin report that early signs of hypoglycaemia are less obvious or different; if you often have hypoglycaemia or find it hard to recognise, talk to your doctor.
• Tell your doctor if you have recently been ill, have kidney or liver problems or exercise more than usual.
• Before travelling abroad, talk to your doctor – a time difference may change your injection and meal schedule.
• In some patients with long-standing type 2 diabetes and heart disease or previous stroke who received pioglitazone with insulin, heart failure developed – report unusual shortness of breath, rapid weight gain or swelling immediately.
• Injecting into the same area may cause skin changes (lumps); insulin injected into such an area may not work well – talk to your doctor before changing the site, as more frequent blood sugar checks or dose adjustment may be needed.
• The medicine is essentially sodium-free (less than 23 mg per dose).

Interactions with other medicines

Your insulin requirements may change if you take:

• steroid hormones, thyroid hormone replacement, growth hormone, danazol
• oral antidiabetic medicines, acetylsalicylic acid (aspirin)
• octreotide, lanreotide
• beta2-sympathomimetics (e.g. ritodrine, salbutamol, terbutaline), beta-blockers
• thiazide diuretics, some antidepressants (monoamine oxidase inhibitors)
• some ACE inhibitors (e.g. captopril, enalapril) or angiotensin II receptor blockers

Alcohol and some medicines may affect blood sugar. Tell your doctor about all medicines you take, including those without a prescription.

Pregnancy and breastfeeding

Insulin requirements usually fall in the first three months of pregnancy and rise in the remaining six months; it is essential that a pregnant woman on insulin is well controlled throughout pregnancy. During breastfeeding the insulin dose or diet may need to be changed. If you are pregnant, planning a pregnancy or breastfeeding, talk to your doctor.

Driving and using machines

During hypoglycaemia your ability to concentrate and react may be reduced, which is dangerous when driving or using machines. Talk to your doctor about driving if you often have hypoglycaemia or have weak or no warning signs.

Possible side effects

• Hypoglycaemia (low blood sugar) – the most important side effect of insulin; first signs are tiredness, nervousness or shaking, headache, fast heartbeat, nausea and cold sweat.
• Common (up to 1 in 10): local allergy – redness, swelling or itching at the injection site, usually clearing within a few days to a few weeks.
• Uncommon (up to 1 in 100): shrinking or thickening of fatty tissue under the skin (lipodystrophy, lipohypertrophy) with frequent injection into the same site; frequency not known: lumps due to amyloid build-up (cutaneous amyloidosis).
• Very rare (up to 1 in 10,000): generalised allergy – fall in blood pressure, rash all over the body, difficulty breathing, wheezing, fast heartbeat, sweating; tell your doctor immediately.
• Oedema (e.g. swelling of hands, ankles, fluid retention), especially at the start of insulin treatment or when treatment is changed to improve blood sugar control.

Hyperglycaemia (high blood sugar) may occur if insulin is not given or a lower dose is given, with overeating, fever, infection or stress; it may lead to diabetic ketoacidosis (drowsiness, flushed face, thirst, loss of appetite, fruity breath, nausea or vomiting). Report suspected side effects to your doctor, pharmacist or ALIMS.

Overdose, missed dose and stopping treatment

• Overdose: a higher dose may lower your blood sugar – check your blood sugar. In mild hypoglycaemia take glucose tablets, sugar or a sweet drink, then fruit, biscuits or a sandwich as advised by your doctor, and rest. More severe hypoglycaemia can be treated with a glucagon injection, after which glucose or sugar should be taken.
• Missed or lower dose: blood sugar may become high – check your blood sugar. Do not inject a double dose to make up for a missed one.
• Stopping treatment: stopping may lead to high blood sugar; do not change your insulin unless your doctor tells you to.
• During illness, especially with nausea and vomiting, your insulin needs change, but you still need insulin even if you are not eating normally – check your blood sugar and inform your doctor.

Related information

For blood sugar self-monitoring, see also the category Blood sugar measuring devices – products in this category do not replace the medicine prescribed for you.

Composition, packaging and manufacturer

• Active substance: human insulin 100 IU/mL (30% soluble insulin and 70% isophane insulin); one cartridge contains 300 IU in 3 mL.
• Excipients: protamine sulphate; m-cresol; phenol; glycerol; disodium phosphate heptahydrate; zinc oxide; water for injections; sodium hydroxide or hydrochloric acid to adjust acidity.
• Pack: 3 mL cartridge of siliconised type I glass with rubber closures and an aluminium cap; carton of 5 cartridges.
• Marketing authorisation holder: Representative office Eli Lilly (Suisse) SA, Belgrade (Novi Beograd), Vladimira Popovića 38-40, Belgrade. Manufacturers: Lilly France, Fegersheim, France; Eli Lilly Italia S.p.A., Sesto Fiorentino, Italy.

Storage

• Before first use: in a refrigerator at 2–8 °C. Do not freeze.
• After first use: below 30 °C for up to 28 days. Do not keep the pen with the cartridge in use in the fridge and do not expose it to heat or direct sunlight.
• Do not use if there are clumps or solid white particles stuck to the bottom and walls of the cartridge (frosted appearance).
• Keep out of the sight and reach of children; return unused medicine to a pharmacy that collects unused medicines.

Frequently asked questions

What does M3 mean in the name Humulin M3?

Humulin M3 is a ready-made mixture: 30% insulin dissolved in water (fast action) and 70% isophane insulin (prolonged action due to protamine). That is why the suspension is milky white and must be carefully mixed before each use.

How do I prepare the cartridge before injecting?

Roll the cartridge between your palms 10 times and turn it up and down 10 times until the contents are evenly cloudy. Do not shake vigorously, as foam may affect dose accuracy. If you see clumps or white particles stuck to the walls, do not use the cartridge.

How long can I use an opened cartridge?

After first use the cartridge is kept below 30 °C for up to 28 days. The pen with the cartridge in use should not be kept in the fridge.

What should I do if I notice signs of hypoglycaemia?

Take glucose tablets, sugar or a sweet drink, then fruit, biscuits or a sandwich, and rest. If your condition worsens, seek medical help immediately. Do not inject Humulin M3 when you think hypoglycaemia is starting.

Sources

• ALIMS – Summary of Product Characteristics, Humulin® M3, 100 IU/mL, suspension for injection in cartridge (SmPC, Serbian)
• ALIMS – Package leaflet, Humulin® M3, 100 IU/mL, suspension for injection in cartridge (PIL, Serbian)

Sources checked on: 25 October 2026.