Humalog KwikPen prefilled pens contain insulin lispro. They are used to treat diabetes.

What is it used for?

  • Diabetes.

How does it work?

  • Humalog vials, Humalog cartridges (for use with Autopen Classic or HumaPen pens) and Humalog KwikPen prefilled pens all contain insulin lispro. They are used to treat diabetes.
  • People with diabetes have a deficiency or absence of a hormone made by the pancreas called insulin. Insulin is the main hormone responsible for controlling levels of sugar (glucose) in the blood.
  • People with type one diabetes need to have injections of insulin to control the amount of glucose in their bloodstream. Insulin injections act as a replacement for natural insulin, and allow people with diabetes to achieve normal blood glucose levels.

The insulin works in the same way as natural insulin, by binding to insulin receptors on cells in the body. Insulin causes cells in the liver, muscle and fat tissue to increase their uptake of glucose form the bloodstream.

It also decreases the production of glucose by the liver, and has various other effects that lower the amount of glucose in the blood.

Humalog injections contain a type of insulin called insulin lispro. This is known as a fast-acting insulin. It works faster but for a shorter length of time than soluble insulin. When it is injected under the skin it starts to lower blood sugar within approximately 15 minutes, and its effects last for two to five hours. This type of insulin should be injected shortly before, or if necessary shortly after a meal, to control increasing blood glucose levels after eating.

Insulin lispro is usually used in combination with intermediate or longer-acting types of insulin, which provide control over blood glucose throughout the day.

It is important to monitor your blood glucose regularly and adjust your insulin dose as required. Your doctor or diabetic team will explain how to do this. Keeping your blood glucose level as close to normal as possible, and not too high or too low, significantly reduces the risk of developing late-stage diabetic complications, such as problems with your nerves, eyesight or kidneys.

How do I use it?

  • Your doctor or diabetes specialist will teach you how to administer your insulin injections correctly. Make sure you understand what to do and ask questions if you don't.
  • Humalog injections are usually given under the skin of the upper arms, thighs, buttocks, or abdomen. You should take care to make sure that the injection does not enter a blood vessel. The injection may start to start to work at different speeds depending on the site you use and various other factors, such as if you have been doing exercise. In general, injections into the abdomen start to work quicker than those given in other areas. You shouldn't massage the injection area after administering an injection. Humalog can also be injected into a vein (intravenously), but only under medical supervision.
  • Each time you inject your insulin make sure you use a different site. This helps to prevent the skin thickening and pitting, which can occur if the injection is repeatedly given in the same site.
  • You should measure your blood sugar levels every day when using insulin injections. The dose you need to inject each time will depend on your blood sugar levels, what you are going to eat and if you have been doing or will be doing exercise. Control of blood sugar is an individual process and your diabetes specialist will help you to understand what is required.
  • Your insulin requirements may increase when you are ill, especially if you have an infection or fever. Your insulin dose may also need adjusting during periods of emotional disturbance, or if you increase your physical activity or change your usual diet. Insulin requirements may be reduced if you have impaired kidney or liver function. Discuss this with your doctor or diabetes nurse to make sure you optimise control of your blood sugar.


  • Low blood sugar (hypoglycaemia) is a potential side effect of insulin therapy. Your diabetes team should give you instructions on how to avoid it. Symptoms of hypoglycaemia usually occur suddenly and may include cold sweats, cool pale skin, tremor, anxious feeling, unusual tiredness or weakness, confusion, difficulty in concentration, excessive hunger, temporary vision changes, headache, nausea and palpitations. You should make sure you know what to do if you experience these symptoms - ask your doctor or diabetes nurse for advice if you are unsure about anything.
  • Your ability to concentrate or react may be reduced if you have low blood sugar, and this can cause problems driving or operating machinery. You should take precautions to avoid low blood sugar when driving - discuss this with your doctor.
  • You should only change your insulin on your doctor's advice. If you do transfer to a different insulin, eg different type (short, intermediate or long acting), different species (human or animal), different brand, or different strength of insulin, your doctor may need to alter your dose, and your warning symptoms of low blood sugar may be slightly different.
  • People with diabetes who are on insulin should only drink alcohol in moderation and accompanied by food. This is because alcohol can make your warning signs of low blood sugar less clear, and can cause delayed low blood sugar, even several hours after drinking.
  • People with diabetes who smoke normally need more insulin, as smoking reduces the amount of insulin that is absorbed into the blood from an injection under the skin. If you give up smoking, you may subsequently need a reduction in your insulin dose. Discuss this with your doctor. (If you are diabetic giving up smoking is one of the most important things you can do, because it will vastly reduce your risk of complications like heart disease and circulatory problems.)

Not to be used in

  • Low blood sugar levels (hypoglycaemia).
  • This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • Insulin lispro has been used by a large number of pregnant women and has not been shown to have any harmful effects on the pregnancy or the health of the newborn baby. Blood sugar levels need to be maintained as stable as possible during pregnancy, and you should consult your diabetic specialist to discuss how to achieve this. Your insulin requirements are likely to decrease in the first trimester and subsequently increase in the second and third trimesters. Discuss this with your doctor.

There is no risk to nursing infants from insulin taken by the mother. However, your insulin dose may need to be adjusted while you are breastfeeding. Discuss this with your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.

Unknown frequency

  • Low blood glucose level (hypoglycaemia).
  • Fluid retention (oedema).

Common (affect between 1 in 10 and 1 in 100 people)

  • Redness, swelling or itching at the injection site.

Uncommon (affect between 1 in 100 and 1 in 1000 people)

  • Skin thickening or pitting (lipodystrophy) if injection given too frequently into the same site.

Rare (affect between 1 in 1000 and 1 in 10,000 people)

  • Allergic reaction (hypersensitivity), such as skin rash or itching, hives, chest tightness, shortness of breath or severe allergic reactions such as anaphylaxis.

The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.

For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

Insulin itself doesn't affect other medicines. However, it is important to be aware that many medicines can affect blood glucose levels and can therefore change your insulin requirements. For this reason, people with diabetes should always seek advice from their doctor or pharmacist before taking any new medicines or stopping existing ones.

The following medicines may decrease blood sugar levels. If you start treatment with any of these your insulin dose may therefore need decreasing:

  • ACE inhibitors, eg captopril (these can sometimes cause unpredictable drops in blood sugar)
  • anabolic steroids, eg testosterone, nandrolone, stanozolol
  • antidiabetic medicines taken by mouth
  • disopyramide
  • fibrates, eg gemfibrozil
  • fluoxetine
  • MAOI antidepressants, eg phenelzine
  • octreotide
  • large doses of salicylates, eg aspirin (small pain relieving doses do not normally have this effect).
  • Beta-blockers, eg propranolol (including eye drops containing beta-blockers) can mask some of the signs of low blood sugar, such as increased heart rate and tremor. They also prolong episodes of low blood sugar and impair recovery back to normal glucose levels.

The following medicines may increase blood glucose levels. If you start treatment with any of these your insulin dose may therefore need increasing:

  • some antipsychotic medicines, eg chlorpromazine, olanzapine
  • corticosteroids, eg hydrocortisone, prednisolone
  • danazol
  • diuretics, especially thiazide diuretics, eg bendroflumethiazide
  • isoniazid
  • lithium
  • protease inhibitors, eg ritonavir
  • somatropin (human growth hormone).

Oestrogens and progestogens, such as those contained in oral contraceptives, may affect blood sugar levels, and women taking these may need small adjustments up or down in their insulin dose.

Where do I store Humalog?

Pre-filled pens: Unused pre-filled pens should be stored in a refrigerator at 2-8°C. Do not freeze. Once in use, the pens should be kept out of the fridge, below 30°C. They can be used for up to 28 days. The pen cap must be put back on the pen after each injection in order to protect from light. The pens should not be stored with the needle attached.

Make sure all medicines are kept out of the reach of children and avoid exposing them to excessive heat or direct sunlight.