Actrapid Penfill: Uses, Dosage & Side Effects
A rapid-acting human insulin used to control blood sugar in people with diabetes mellitus, administered by subcutaneous injection before meals
Actrapid Penfill is a rapid-acting human insulin used to lower high blood sugar in people with diabetes mellitus. It contains soluble human insulin produced by recombinant DNA technology and is designed specifically for use with Novo Nordisk reusable injection pens. Actrapid begins working approximately 30 minutes after injection and its blood sugar-lowering effect lasts for about 8 hours. It is most commonly used in combination with intermediate-acting or long-acting insulin to provide both mealtime and basal glucose control. Human insulin is classified as an essential medicine by the World Health Organization and remains one of the most widely prescribed treatments for diabetes worldwide.
Quick Facts: Actrapid Penfill
Key Takeaways
- Actrapid Penfill is a rapid-acting soluble human insulin that starts working within 30 minutes and lasts approximately 8 hours, making it ideal for mealtime blood sugar control.
- You must eat a meal or snack containing carbohydrates within 30 minutes of injecting Actrapid to prevent dangerously low blood sugar (hypoglycemia).
- Actrapid Penfill must not be used in insulin pumps — it is designed exclusively for subcutaneous injection with Novo Nordisk reusable pens.
- Always rotate injection sites to prevent skin changes (lipodystrophy), and never share needles or pens with another person.
- Store unopened cartridges in the refrigerator (2–8°C); once in use, keep at room temperature (up to 30°C) for a maximum of 6 weeks.
What Is Actrapid Penfill and What Is It Used For?
Actrapid is a rapid-acting (soluble) human insulin manufactured by Novo Nordisk using recombinant DNA technology. The term “Penfill” refers to the cartridge format, which is designed to fit into Novo Nordisk reusable injection pens. Unlike insulin analogues (such as insulin lispro or insulin aspart), Actrapid contains unmodified human insulin — structurally identical to the insulin naturally produced by the pancreas. This makes it one of the most established and widely used insulin formulations in the world.
Diabetes mellitus is a chronic metabolic condition characterised by the body's inability to produce sufficient insulin or to use insulin effectively. In type 1 diabetes, the immune system destroys the insulin-producing beta cells of the pancreas, leading to complete insulin deficiency. These patients require lifelong insulin replacement from the time of diagnosis. In type 2 diabetes, the body becomes resistant to insulin's effects and may eventually lose the ability to produce enough insulin. Many people with advanced type 2 diabetes require insulin therapy when oral medications alone no longer provide adequate blood sugar control.
Actrapid is specifically designed for mealtime (prandial) use. When you eat food containing carbohydrates, your blood sugar rises. Actrapid provides a burst of insulin activity that helps your cells absorb this glucose, preventing dangerous spikes in blood sugar after meals. It begins to lower blood sugar approximately 30 minutes after subcutaneous injection, reaches its peak effect between 1.5 and 3.5 hours, and has a total duration of action of approximately 7 to 8 hours. Because of this 30-minute onset, patients are advised to inject Actrapid approximately half an hour before eating.
Actrapid is most commonly prescribed as part of a basal-bolus insulin regimen. In this approach, a longer-acting insulin (such as insulin glargine, insulin detemir, or isophane insulin/Insulatard) provides a steady background level of insulin throughout the day and night, while Actrapid is injected before each main meal to handle the post-meal blood sugar rise. This combination closely mimics the natural pattern of insulin secretion in people without diabetes, providing both continuous baseline coverage and mealtime bursts of insulin activity.
According to the International Diabetes Federation, approximately 537 million adults worldwide live with diabetes, and this number continues to rise. Insulin therapy — including rapid-acting formulations like Actrapid — remains a cornerstone of diabetes management. Human insulin is included on the WHO Model List of Essential Medicines, reflecting its critical importance in global healthcare. Actrapid has been available for decades and is approved for use in adults, adolescents, and children with diabetes mellitus requiring insulin treatment.
What Should You Know Before Taking Actrapid Penfill?
Contraindications
You should not use Actrapid Penfill in the following circumstances:
- Allergy: If you are allergic (hypersensitive) to human insulin or any of the other ingredients in Actrapid (zinc chloride, glycerol, metacresol, sodium hydroxide, hydrochloric acid, or water for injections).
- Hypoglycemia: If you feel the onset of hypoglycemia (low blood sugar symptoms such as sweating, trembling, rapid heartbeat, confusion, or dizziness), do not inject additional insulin.
- Insulin pumps: Actrapid Penfill must never be used in insulin infusion pumps. The cartridge is designed exclusively for use with compatible Novo Nordisk reusable pens.
- Damaged product: If the cartridge or pen device has been dropped, damaged, or crushed, do not use it.
- Improper storage: If the insulin has not been stored correctly or has been frozen, it must be discarded.
- Appearance: If the solution is not clear and colorless, do not use it.
Warnings and Precautions
Before and during treatment with Actrapid Penfill, discuss the following important considerations with your healthcare provider:
- Kidney, liver, or endocrine problems: If you have impaired kidney or liver function, or conditions affecting the adrenal glands, pituitary gland, or thyroid, your insulin requirements may change significantly. Your doctor may need to adjust your dose and increase the frequency of blood sugar monitoring.
- Physical activity changes: If you exercise more than usual or wish to change your diet significantly, your blood sugar levels can be affected and your insulin dose may need to be adjusted. Increased physical activity generally lowers blood sugar, potentially requiring a reduction in insulin dose or additional carbohydrate intake.
- Illness: If you become unwell with an infection, fever, or other illness, your insulin requirements may increase even if you are eating less. Continue taking your insulin and contact your healthcare provider for guidance on dose adjustments. Never stop insulin therapy without medical supervision.
- Travel: Travelling across time zones can affect your insulin schedule and requirements. Discuss adjustments with your doctor before travelling internationally.
Repeatedly injecting in the same area can cause the fat tissue under the skin to thicken (lipohypertrophy), shrink (lipoatrophy), or develop lumps caused by amyloid protein deposits (cutaneous amyloidosis). Insulin may not work as effectively if injected into an area with these changes. Always rotate your injection site within the same body region to help prevent these skin changes. If you notice any changes at injection sites, inform your doctor before switching to a different area, as your blood sugar monitoring and insulin dose may need adjustment.
Pregnancy and Breastfeeding
If you are pregnant, believe you may be pregnant, or are planning to become pregnant, consult your doctor before using Actrapid. Insulin is the preferred treatment for diabetes during pregnancy because it does not cross the placenta in significant amounts and is considered safe for the developing baby. Maintaining careful blood sugar control during pregnancy is critically important to prevent complications for both mother and child, including pre-eclampsia, macrosomia (large baby), birth defects, and neonatal hypoglycemia.
Insulin requirements typically change throughout pregnancy. They may decrease during the first trimester and then increase significantly during the second and third trimesters as insulin resistance increases. After delivery, insulin needs usually drop rapidly and may require prompt adjustment. Careful monitoring by your healthcare team is essential throughout pregnancy and the postpartum period.
There are no restrictions on using Actrapid during breastfeeding. Insulin does not pass into breast milk in a way that could affect the nursing infant. However, your insulin dose and dietary plan may need to be adjusted during breastfeeding, as lactation can lower blood sugar levels.
Use in Children and Adolescents
Actrapid can be used in children and adolescents of all ages who require insulin therapy for diabetes. Dosing for children must be individually determined by a paediatric endocrinologist based on the child's age, weight, blood sugar levels, physical activity, and growth stage. Parents and caregivers must be thoroughly trained in injection technique, blood sugar monitoring, and recognizing and treating hypoglycemia. Insulin requirements may change during puberty and periods of rapid growth.
Driving and Operating Machinery
Your ability to concentrate and react may be impaired if you experience hypoglycemia (low blood sugar) or hyperglycemia (high blood sugar). This could put you and others at risk when driving or operating machinery. Ask your doctor whether it is safe for you to drive if you frequently experience low blood sugar episodes or if your warning symptoms of hypoglycemia are weakened or absent (hypoglycemia unawareness). Carry a source of fast-acting sugar in your vehicle at all times.
Sodium Content
Actrapid Penfill contains less than 1 mmol sodium (23 mg) per dose, meaning it is essentially sodium-free. This is relevant for patients on a controlled sodium diet.
How Does Actrapid Penfill Interact with Other Drugs?
Drug interactions with insulin are clinically significant because they can either increase or decrease blood sugar levels, sometimes unpredictably. Understanding these interactions is essential for safe diabetes management. Your doctor may need to adjust your Actrapid dose when you start, stop, or change the dose of another medication. Always inform your healthcare team about every medication you are taking.
Drugs That May Lower Blood Sugar (Increase Hypoglycemia Risk)
The following medications can enhance the blood sugar-lowering effect of Actrapid. When these drugs are used in combination with insulin, your risk of hypoglycemia increases and closer blood sugar monitoring is recommended:
| Drug/Class | Primary Indication | Interaction Mechanism |
|---|---|---|
| Other antidiabetic drugs (metformin, sulfonylureas, GLP-1 agonists) | Diabetes | Additive blood sugar-lowering effect |
| MAO inhibitors (e.g. moclobemide, phenelzine) | Depression | May potentiate insulin effect and reduce counter-regulatory response |
| Beta-blockers (e.g. atenolol, metoprolol, propranolol) | High blood pressure, heart conditions | May enhance insulin action; also mask hypoglycemia warning signs |
| ACE inhibitors (e.g. enalapril, ramipril, lisinopril) | High blood pressure, heart failure | May increase insulin sensitivity |
| Salicylates (e.g. aspirin, high doses) | Pain, inflammation, fever | Reduces hepatic glucose production |
| Anabolic steroids (e.g. testosterone) | Hormone replacement, muscle wasting | Increases insulin sensitivity and glucose uptake |
| Sulfonamide antibiotics | Bacterial infections | May enhance insulin secretion and effect |
Drugs That May Raise Blood Sugar (Decrease Insulin Effectiveness)
The following medications can counteract the effects of insulin and raise blood sugar levels. An increase in Actrapid dose may be required when starting these medications:
| Drug/Class | Primary Indication | Interaction Mechanism |
|---|---|---|
| Oral contraceptives (oestrogen/progestogen) | Contraception | Increases insulin resistance |
| Thiazide diuretics (e.g. hydrochlorothiazide) | High blood pressure, fluid retention | Impairs insulin secretion, potassium depletion |
| Glucocorticoids (e.g. prednisolone, dexamethasone) | Inflammation, autoimmune conditions | Increases insulin resistance and hepatic glucose output |
| Thyroid hormones (e.g. levothyroxine) | Hypothyroidism | Increases glucose absorption and production |
| Sympathomimetics (e.g. adrenaline, salbutamol, terbutaline) | Asthma, allergic reactions | Stimulates glycogenolysis and gluconeogenesis |
| Growth hormone (somatropin) | Growth hormone deficiency | Counter-regulatory to insulin; increases blood glucose |
| Danazol | Endometriosis, fibrocystic breast disease | Interferes with glucose metabolism |
Drugs with Variable Effects on Blood Sugar
Octreotide and lanreotide, used for acromegaly (a rare hormonal disorder involving excess growth hormone production), may either raise or lower blood sugar levels depending on the individual circumstances. These medications require particularly careful blood sugar monitoring when used alongside insulin therapy.
Beta-blockers deserve special attention because, in addition to potentially lowering blood sugar, they can mask the typical warning signs of hypoglycemia — particularly the rapid heartbeat and trembling that normally alert patients to falling blood sugar levels. If you take a beta-blocker, you may need to rely on other symptoms (such as sweating or hunger) and more frequent blood glucose testing to detect low blood sugar.
Pioglitazone (an oral diabetes medication) used in combination with insulin has been associated with heart failure in some patients with long-standing type 2 diabetes and pre-existing heart disease or previous stroke. If you take pioglitazone with insulin, inform your doctor immediately if you experience signs of heart failure such as unusual shortness of breath, rapid weight gain, or localised swelling (oedema).
Alcohol
Alcohol can affect your insulin requirements unpredictably. It may initially raise blood sugar (particularly sweet or mixed drinks) but can cause a delayed and prolonged drop in blood sugar levels, especially when consumed without food. The liver prioritises metabolising alcohol over releasing glucose, impairing the body's ability to correct low blood sugar. If you choose to drink alcohol, do so in moderation, always eat food alongside it, monitor your blood sugar more frequently, and be aware that symptoms of hypoglycemia can be mistaken for intoxication by others.
Always tell your doctor or pharmacist about all medications you are taking, including prescription drugs, over-the-counter medicines, herbal supplements, and vitamins. Never start or stop a medication without discussing the potential impact on your blood sugar control with your healthcare provider.
What Is the Correct Dosage of Actrapid Penfill?
The dosage of Actrapid is highly individualised and there is no single dose that works for everyone. Your doctor will determine your starting dose and make adjustments over time based on regular blood sugar monitoring, HbA1c levels, your diet, physical activity, body weight, other medications, and any concurrent illnesses. The overall aim of insulin therapy is to maintain blood sugar levels as close to normal as possible while minimising the risk of hypoglycemia.
Adults
Standard Mealtime Dosing
Actrapid is injected subcutaneously 30 minutes before a meal containing carbohydrates. The dose is determined by your doctor and is based on your individual blood sugar readings and dietary carbohydrate intake. In a typical basal-bolus regimen, mealtime insulin (such as Actrapid) accounts for approximately 50–60% of the total daily insulin dose, divided across main meals, while the remaining 40–50% is provided by a longer-acting basal insulin given once or twice daily.
Combination with Basal Insulin
Actrapid is most often used together with an intermediate-acting insulin such as Insulatard (isophane/NPH insulin) or a long-acting insulin analogue such as insulin glargine (Lantus) or insulin detemir (Levemir). If your doctor changes you from one type of insulin to another, your dose may need to be adjusted. Only switch insulin types under medical supervision.
Children and Adolescents
Paediatric Dosing
Actrapid can be used in children and adolescents of all ages. The dose is individually determined by the child's paediatric endocrinologist based on age, weight, blood sugar levels, physical activity, and growth stage. Insulin requirements may change significantly during puberty and periods of rapid growth. Parents and caregivers must be trained in injection technique, blood sugar monitoring, and hypoglycemia management.
Elderly Patients
Older Adults (65+ years)
In elderly patients, progressive deterioration of kidney function may lead to a gradual decrease in insulin requirements. If you are over 65, you should monitor your blood sugar more regularly and discuss any changes in your insulin dose with your doctor. Blood sugar targets may be less strict in older adults to reduce the risk of hypoglycemia, which can be particularly dangerous in this population due to increased fall risk and cardiovascular vulnerability.
Kidney or Liver Impairment
If you have impaired kidney or liver function, your insulin requirements may be reduced because insulin is metabolised and cleared more slowly. More frequent blood sugar monitoring is essential, and your doctor may need to adjust your dose accordingly.
How and Where to Inject
Actrapid Penfill is injected subcutaneously (under the skin) only. It must never be injected into a vein (intravenously) or a muscle (intramuscularly), as this would dramatically alter its absorption and could cause severe and unpredictable blood sugar changes. Actrapid Penfill cartridges are designed exclusively for use with Novo Nordisk reusable injection pens and NovoFine or NovoTwist injection needles.
The recommended injection sites include:
- Abdomen (front of the waist): Provides the fastest and most consistent absorption. This is the preferred site when rapid onset is desired.
- Buttocks: Good alternative injection site with reliable absorption.
- Front of thighs: Slightly slower absorption compared to the abdomen.
- Upper arms: Suitable but may be difficult to self-inject.
Rotate injection sites within the same body region at each injection to reduce the risk of lipodystrophy (skin thickening, shrinking, or lumps at injection sites). Use a new needle for every injection to prevent contamination. After inserting the needle, hold it under the skin for at least 6 seconds with the injection button fully pressed to ensure the complete dose is delivered. Always remove and safely discard the needle after each injection — never store the pen with a needle attached, as this can cause leakage and inaccurate dosing.
Actrapid Penfill cartridges are designed for single use only and must not be refilled. When the cartridge is empty, discard it properly. If you use both Actrapid Penfill and another insulin in Penfill cartridges, use two separate pen devices — one for each type of insulin — to prevent mix-ups. Always carry a spare cartridge in case the one in use is lost or damaged.
Missed Dose
If you forget to take your Actrapid before a meal, your blood sugar may rise too high (hyperglycemia). Do not take a double dose to make up for a forgotten injection. Check your blood sugar more frequently and contact your doctor or diabetes nurse for guidance if your blood sugar remains elevated. For information on managing hyperglycemia, see the side effects section below.
Overdose
If you inject too much Actrapid, your blood sugar may drop to dangerously low levels (hypoglycemia). For mild symptoms (sweating, trembling, hunger), immediately consume 15–20 grams of fast-acting carbohydrates such as glucose tablets, fruit juice, or sugar-sweetened drinks. Recheck your blood sugar after 15 minutes and repeat if necessary. Severe hypoglycemia — where you are unable to treat yourself or become unconscious — is a medical emergency. Someone nearby should administer a glucagon injection and call emergency services immediately. Do not give food or drink to an unconscious person.
Stopping insulin therapy abruptly, especially in type 1 diabetes, can lead to diabetic ketoacidosis (DKA) — a life-threatening condition where the body breaks down fat instead of sugar for energy, causing a dangerous build-up of acids (ketones) in the blood. Symptoms include excessive thirst, frequent urination, nausea, vomiting, abdominal pain, rapid deep breathing, facial flushing, and drowsiness. DKA requires immediate hospital treatment. Very high blood sugar (severe hyperglycemia) and ketoacidosis can lead to diabetic coma and, if untreated, death. Never stop or reduce your insulin without your doctor's guidance.
What Are the Side Effects of Actrapid Penfill?
Like all medicines, Actrapid can cause side effects, although not everyone experiences them. Understanding the potential side effects and their frequency helps you recognise them early and take appropriate action. The side effects listed below are classified by how commonly they occur according to international pharmacovigilance standards:
Very Common
May affect more than 1 in 10 people
- Hypoglycemia (low blood sugar) — The most frequent and potentially most serious side effect. Can occur if you inject too much insulin, eat too little, skip a meal, exercise more than usual, or drink alcohol. Symptoms include cold sweating, cool pale skin, headache, rapid heartbeat, nausea, intense hunger, temporary visual disturbances, drowsiness, unusual tiredness and weakness, anxiety, trembling, nervousness, confusion, and difficulty concentrating. Severe hypoglycemia can lead to loss of consciousness, seizures, brain damage, and — if prolonged and untreated — death.
Uncommon
May affect up to 1 in 100 people
- Local allergic reactions — Pain, redness, hives (urticaria), inflammation, bruising, swelling, and itching at the injection site. These reactions usually resolve within a few weeks of continued treatment. If they persist or spread beyond the injection site, contact your doctor immediately.
- Visual disturbances — At the start of insulin treatment or when blood sugar control changes rapidly, temporary changes in vision may occur. These are usually transient and resolve as blood sugar levels stabilise.
- Swollen joints — When starting insulin therapy, the body may temporarily retain fluid, causing swelling around the ankles and other joints. This usually resolves on its own; if it persists, consult your doctor.
- Painful neuropathy — If blood sugar levels improve very rapidly, nerve-related pain (acute painful neuropathy) may occur. This is typically temporary and self-limiting.
- Lipodystrophy — Changes in fat tissue at injection sites, including thickening (lipohypertrophy) or shrinking (lipoatrophy). These can affect insulin absorption and are prevented by rotating injection sites.
Very Rare
May affect up to 1 in 10,000 people
- Severe allergic reactions (systemic anaphylaxis) — Life-threatening allergic reactions that can include widespread skin reactions, swelling of the face or throat, difficulty breathing, rapid heartbeat, sweating, nausea, vomiting, and a drop in blood pressure. This is a medical emergency — seek immediate medical help and call emergency services.
- Diabetic retinopathy worsening — In patients with pre-existing diabetic retinopathy (diabetic eye disease), very rapid improvement in blood sugar control can paradoxically cause a temporary worsening of retinopathy. Discuss this risk with your eye doctor if you have diabetic eye disease.
Not Known (Frequency Cannot Be Estimated)
Reported from post-marketing experience
- Cutaneous amyloidosis — Lumps under the skin caused by accumulation of amyloid protein. If you inject into an area with lumps, insulin may not be absorbed effectively. Change injection sites regularly to help prevent this.
Recognising and Managing Hypoglycemia
Because hypoglycemia is the most important side effect of Actrapid, understanding how to recognise and manage it is crucial for every person using insulin:
Step 1: Do not inject more insulin. Immediately consume 15–20 grams of fast-acting sugar: glucose tablets, sugar cubes, fruit juice, or a sugar-sweetened drink. Artificial sweeteners do NOT help.
Step 2: Follow up with a slower-acting carbohydrate (bread, crackers, or a meal) to prevent blood sugar from dropping again.
Step 3: Check your blood sugar after 15 minutes. If it is still low, repeat step 1.
Step 4: When symptoms have resolved and blood sugar has stabilised, resume your normal insulin treatment.
If unconscious: Someone nearby must administer a glucagon injection and call emergency services immediately. Do NOT attempt to give food or drink to an unconscious person. Once consciousness is regained, give glucose or a sugary snack. If there is no response to glucagon, hospital treatment is required.
Inform people around you — family, friends, colleagues — that you have diabetes and what the consequences of hypoglycemia can be. Tell them that if you become unconscious, they should place you on your side (recovery position) and call emergency services immediately. They must not give you food or drink, as there is a risk of choking.
Recognising and Managing Hyperglycemia
Hyperglycemia (high blood sugar) can occur if you have not injected enough insulin, if you forget a dose, if you eat more than usual, or if you exercise less than planned. Warning symptoms develop gradually and include: increased urination, thirst, loss of appetite, nausea or vomiting, drowsiness or fatigue, facial flushing, dry skin, dry mouth, and a fruity-smelling breath (acetone). These symptoms may indicate diabetic ketoacidosis — a serious, life-threatening condition that occurs when the body breaks down fat instead of sugar because of insufficient insulin. If you experience these symptoms, test your blood sugar and urine for ketones immediately and contact your doctor or seek emergency medical care urgently.
How Should You Store Actrapid Penfill?
Proper storage of insulin is critical for maintaining its effectiveness. Insulin that has been stored incorrectly may lose its potency without any visible changes, leading to unexpectedly poor blood sugar control. Follow these guidelines to ensure your Actrapid Penfill remains safe and effective:
Unopened (Not Yet in Use)
- Store in a refrigerator at 2–8°C
- Do not place near the freezer compartment — freezing permanently damages insulin
- Do not freeze — frozen insulin must be discarded and never used
- Keep in the outer carton to protect from light
- Check the expiry date (EXP) before use — the expiry date refers to the last day of the stated month
In Use or Carried as a Spare
- Store at room temperature up to 30°C
- Do not refrigerate or freeze once in use
- Can be kept at room temperature for up to 6 weeks
- Always keep the cartridge in the outer carton to protect from light when not in use
- Discard after 6 weeks of first use, even if insulin remains in the cartridge
Inspect the insulin before use. Actrapid should be a clear, colorless, water-like solution with no visible particles or cloudiness. Do not use if the solution appears cloudy, discoloured, or contains any solid particles. If you notice unexpectedly poor blood sugar control, your insulin may have lost effectiveness due to improper storage — replace it with a fresh cartridge.
Remove and safely discard the injection needle after every use. Keep insulin and all medicines out of the sight and reach of children. Do not dispose of insulin via household waste or sewage. Return unused or expired insulin to your pharmacy for safe, environmentally responsible disposal.
What Does Actrapid Penfill Contain?
Active Ingredient
The active substance is human insulin (insulinum humanum). Each millilitre of solution contains 100 IU (international units) of human insulin. Each Penfill cartridge contains 3 ml, providing a total of 300 IU per cartridge. The human insulin in Actrapid is produced by recombinant DNA technology in Saccharomyces cerevisiae (baker's yeast) and is structurally identical to the insulin produced naturally by the human pancreas. This ensures high purity and consistent quality with minimal risk of immunological reactions compared to older animal-derived insulin preparations.
As a soluble (neutral) insulin, the insulin molecules in Actrapid are fully dissolved in the solution, which is why the preparation appears clear and colorless. This soluble form enables rapid absorption after subcutaneous injection, providing the quick onset of action that characterises mealtime insulin coverage.
Inactive Ingredients (Excipients)
| Ingredient | Purpose |
|---|---|
| Zinc chloride | Stabilises insulin hexamers and assists in prolonging action |
| Glycerol | Tonicity agent (makes the solution isotonic with body fluids) |
| Metacresol | Preservative (antimicrobial agent to prevent bacterial growth) |
| Sodium hydroxide | pH adjustment |
| Hydrochloric acid | pH adjustment |
| Water for injections | Solvent (vehicle for the active ingredient) |
Actrapid Penfill contains less than 1 mmol sodium (23 mg) per dose, meaning it is essentially sodium-free. This is relevant for patients on controlled sodium diets.
Available Forms and Pack Sizes
Actrapid Penfill is available as a clear, colorless solution for injection in 3 ml glass cartridges (Penfill). Each cartridge contains 300 IU of human insulin. The cartridges are packaged in cartons containing 1, 5, or 10 cartridges. Not all pack sizes may be available in all countries. The cartridges are designed for use with Novo Nordisk reusable injection pens and are compatible with NovoFine and NovoTwist injection needles.
Manufacturer
Actrapid Penfill is manufactured by Novo Nordisk A/S, Novo Allé, DK-2880 Bagsværd, Denmark. The manufacturing site can be identified by the batch number printed on the carton and label. Novo Nordisk also operates a manufacturing facility in Chartres, France. Novo Nordisk is one of the world's leading producers of insulin and diabetes care products, with over 100 years of experience in insulin development and manufacturing.
Frequently Asked Questions About Actrapid Penfill
Actrapid is a rapid-acting (soluble) human insulin that starts working within 30 minutes and lasts approximately 8 hours. It is specifically designed to control blood sugar spikes after meals and should be injected about 30 minutes before eating. Long-acting insulins such as insulin glargine (Lantus, Toujeo) and insulin detemir (Levemir) provide a slow, steady baseline of insulin over 18–24 hours and are usually injected once or twice daily regardless of meals. Most people with type 1 diabetes use both types together in a basal-bolus regimen: Actrapid before meals for mealtime coverage and a long-acting insulin for continuous background insulin levels.
No, Actrapid Penfill must not be used in insulin infusion pumps. The Penfill cartridge is designed exclusively for use with Novo Nordisk reusable injection pens and compatible NovoFine or NovoTwist needles. Using Actrapid Penfill in a pump could lead to pump malfunction, incorrect dosing, and potentially dangerous blood sugar fluctuations. If you require continuous subcutaneous insulin infusion via an insulin pump, your doctor will prescribe an insulin formulation that is specifically approved and tested for pump use.
Actrapid begins lowering blood sugar approximately 30 minutes after injection. If you do not eat a meal or snack containing carbohydrates within this timeframe, the insulin will continue to lower your blood sugar without the incoming glucose from food to balance it, leading to hypoglycemia (low blood sugar). The timing of the injection relative to your meal is important for safe and effective blood sugar control. If circumstances prevent you from eating within 30 minutes, contact your healthcare provider for guidance on managing this situation.
If you use both Actrapid Penfill and another insulin in Penfill cartridge format, you must use two separate pen devices — one for each type of insulin. Do not mix different insulins in the same cartridge or pen. Mixing insulins can alter the onset and duration of action, leading to unpredictable blood sugar control. Your doctor will advise you on how to coordinate the timing and dosing of multiple insulin types for optimal blood sugar management.
Once a Penfill cartridge is in use or being carried as a spare, it can be stored at room temperature (up to 30°C) for a maximum of 6 weeks. After 6 weeks, the cartridge should be discarded even if insulin remains inside, as the preservative effectiveness and insulin stability may decline. Unopened cartridges should be stored in the refrigerator at 2–8°C. Never freeze insulin — freezing permanently destroys it and the cartridge must be discarded. Always protect cartridges from direct sunlight and heat.
If your Actrapid Penfill has been frozen, you must discard it immediately and use a fresh cartridge. Freezing permanently damages the insulin protein, rendering it ineffective even though the solution may still appear clear after thawing. Using frozen-and-thawed insulin can lead to unpredictable blood sugar control and potentially dangerous hyperglycemia. To prevent accidental freezing, do not store insulin directly against the back wall of the refrigerator (which is often the coldest area) or in contact with the freezer compartment. When travelling in cold weather, keep insulin close to your body for warmth rather than in outer bags or luggage compartments.
References
- World Health Organization. WHO Model List of Essential Medicines – 23rd List. Geneva: WHO; 2023. Human insulin is classified as an essential medicine for diabetes management worldwide.
- European Medicines Agency. Actrapid (Soluble Human Insulin) – Summary of Product Characteristics. EMA; 2024. Official European prescribing information for soluble human insulin.
- American Diabetes Association. Standards of Care in Diabetes – 2025. Diabetes Care. 2025;48(Suppl 1). Comprehensive evidence-based clinical practice recommendations for diabetes management.
- Davies MJ, Aroda VR, Collins BS, et al. Management of Hyperglycemia in Type 2 Diabetes, 2022. A Consensus Report by the ADA and EASD. Diabetes Care. 2022;45(11):2753-2786. doi:10.2337/dci22-0034
- International Diabetes Federation. IDF Diabetes Atlas, 10th edition. Brussels: IDF; 2021. Global epidemiological data on diabetes prevalence and projections.
- Novo Nordisk A/S. Actrapid Penfill – Patient Information Leaflet. Bagsværd, Denmark: Novo Nordisk; 2020. Official patient information for Actrapid Penfill cartridges.
- Hirsch IB. Insulin analogues. New England Journal of Medicine. 2005;352(2):174-183. doi:10.1056/NEJMra040832. Comprehensive review of insulin pharmacology and clinical applications.
- DeWitt DE, Hirsch IB. Outpatient insulin therapy in type 1 and type 2 diabetes mellitus: scientific review. JAMA. 2003;289(17):2254-2264. doi:10.1001/jama.289.17.2254
- Holman RR, Thorne KI, Farmer AJ, et al. Addition of biphasic, prandial, or basal insulin to oral therapy in type 2 diabetes. New England Journal of Medicine. 2007;357(17):1716-1730. doi:10.1056/NEJMoa075392
- U.S. Food and Drug Administration. Insulin Human Injection – Prescribing Information. FDA; 2024. Official U.S. prescribing information for soluble human insulin products.
Editorial Team
This article has been written and reviewed by the iMedic medical editorial team according to our strict editorial standards. Our team consists of licensed physicians, pharmacists, and medical researchers with expertise in endocrinology, diabetology, and clinical pharmacology.
Content developed by iMedic's medical writing team based on current international guidelines (WHO, EMA, FDA, ADA, EASD) and peer-reviewed endocrinological research.
Independently reviewed and fact-checked by the iMedic Medical Review Board, comprising board-certified specialists in endocrinology, diabetology, and clinical pharmacology.
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