Liprolog Mix25 KwikPen
Biphasic insulin lispro – pre-filled insulin pen for diabetes management
Quick Facts about Liprolog Mix25 KwikPen
Key Takeaways about Liprolog Mix25 KwikPen
- Biphasic insulin with dual action: Combines 25% rapid-acting insulin lispro with 75% intermediate-acting insulin lispro protamine for both mealtime and basal glucose control
- Inject within 15 minutes before meals: The rapid-acting component starts working within 15 minutes, so inject shortly before eating
- Always re-suspend before use: Roll the pen 10 times and invert 10 times to mix the suspension evenly before each injection
- Hypoglycemia is the main risk: Monitor blood glucose regularly and always carry a fast-acting sugar source such as glucose tablets
- Never share pens between patients: Even with a new needle, shared pens carry a risk of cross-contamination and bloodborne infection
What Is Liprolog Mix25 KwikPen and What Is It Used For?
Liprolog Mix25 KwikPen is a biphasic insulin analogue used to treat diabetes mellitus in patients who require insulin to control their blood sugar levels. It contains a mixture of 25% rapid-acting insulin lispro and 75% intermediate-acting insulin lispro protamine suspension, delivered via a convenient pre-filled disposable pen.
Liprolog Mix25 KwikPen belongs to a class of medicines called biphasic insulin analogues. Insulin is a hormone naturally produced by the pancreas that enables cells throughout the body to absorb glucose (sugar) from the bloodstream and use it for energy. In people with diabetes, the body either does not produce enough insulin (type 1 diabetes) or cannot use insulin effectively (type 2 diabetes), resulting in elevated blood glucose levels that can cause serious long-term health complications if left untreated.
The active ingredient in Liprolog Mix25 KwikPen is insulin lispro, a genetically engineered human insulin analogue produced by recombinant DNA technology using Escherichia coli. Insulin lispro differs from regular human insulin by a reversal of two amino acids (proline and lysine) at positions 28 and 29 of the B-chain. This small structural modification causes insulin lispro to be absorbed more rapidly from the injection site compared with regular human insulin, providing faster onset and shorter duration of action.
The "Mix25" formulation is specifically designed to provide a convenient two-phase insulin profile in a single injection. The 25% rapid-acting insulin lispro component addresses postprandial (after-meal) glucose spikes by working within 15 minutes of injection, while the 75% intermediate-acting insulin lispro protamine suspension provides a sustained basal insulin effect lasting up to 15 hours. This combination reduces the total number of daily injections needed compared with separate rapid-acting and basal insulin regimens.
The "KwikPen" refers to the pre-filled, disposable pen device manufactured by Eli Lilly. Each pen contains 3 mL of insulin suspension at a concentration of 100 units per millilitre (300 units total). The pen is designed for ease of use, with a simple dose dial that allows patients to select their prescribed dose in 1-unit increments. The pen should be used with compatible pen needles (not included), and a new needle must be attached before each injection.
Liprolog Mix25 KwikPen contains a pre-mixed suspension, whereas Liprolog (without "Mix") contains only rapid-acting insulin lispro solution. Never switch between insulin products without medical supervision, as this requires dose adjustment and careful blood glucose monitoring. Always check the label before injecting.
What Should You Know Before Taking Liprolog Mix25 KwikPen?
Before using Liprolog Mix25 KwikPen, tell your doctor about all medical conditions, other medications, and whether you are pregnant or breastfeeding. Do not use this medicine if you are allergic to insulin lispro or if your blood sugar is already too low (hypoglycemia). Your doctor will determine the correct dose based on your individual needs.
Contraindications
You must not use Liprolog Mix25 KwikPen if:
- You are allergic to insulin lispro or any of the other ingredients in this medicine (metacresol, protamine sulfate, phenol, glycerol, dibasic sodium phosphate, zinc oxide, or water for injections)
- You are experiencing hypoglycemia (low blood sugar) — never inject insulin when your blood glucose is already too low
If you are unsure whether any of the above apply to you, consult your doctor or pharmacist before using this medicine. Your doctor may need to prescribe an alternative insulin product or adjust your treatment plan accordingly.
Warnings and Precautions
Talk to your doctor, pharmacist, or diabetes nurse before using Liprolog Mix25 KwikPen if you:
- Have kidney or liver problems — these conditions can alter how your body processes insulin, requiring dose adjustments
- Are exercising more than usual or changing your diet — physical activity and food intake significantly affect blood glucose levels and insulin requirements
- Are ill or under stress — illness, emotional stress, and infections can increase blood glucose levels, potentially requiring temporary dose increases
- Are planning to travel across time zones — changes in meal timing and activity levels may require adjustments to your insulin schedule
- Drink alcohol — alcohol can unpredictably lower or raise blood glucose levels, and the warning signs of hypoglycemia may be masked
- Take thiazolidinediones (such as pioglitazone) in combination with insulin, as this increases the risk of heart failure due to fluid retention
Liprolog Mix25 KwikPen must never be shared between patients, even if the needle is changed. Sharing insulin pens carries a serious risk of cross-contamination and transmission of bloodborne pathogens such as hepatitis B, hepatitis C, and HIV.
Pregnancy and Breastfeeding
If you are pregnant, planning to become pregnant, or breastfeeding, tell your doctor before using Liprolog Mix25 KwikPen. Insulin lispro is considered safe for use during pregnancy, and maintaining good blood glucose control is essential for the health of both mother and baby. However, insulin requirements change significantly throughout pregnancy:
- First trimester: Insulin needs typically decrease due to hormonal changes and reduced caloric intake from morning sickness
- Second and third trimesters: Insulin needs generally increase, sometimes substantially, due to placental hormones that cause insulin resistance
- After delivery: Insulin requirements usually drop rapidly and return to pre-pregnancy levels within days
Insulin lispro is compatible with breastfeeding. Women with diabetes who are breastfeeding may need adjustments to their insulin dose and/or diet. Regular blood glucose monitoring is important during this period.
How Does Liprolog Mix25 KwikPen Interact with Other Drugs?
Several medications can affect how Liprolog Mix25 KwikPen works. Some drugs increase the blood-sugar-lowering effect (raising hypoglycemia risk), while others reduce it (potentially causing hyperglycemia). Always inform your doctor about all medicines, supplements, and herbal products you take.
Drug interactions with insulin are clinically significant because they can push blood glucose dangerously low (hypoglycemia) or dangerously high (hyperglycemia). The following tables summarise the most important interactions. Your prescribing physician or specialist diabetes nurse should review all your medications regularly to ensure safe and effective use of Liprolog Mix25 KwikPen.
| Drug / Class | Effect on Insulin | Clinical Significance | Action Required |
|---|---|---|---|
| Sulfonylureas (e.g. glibenclamide, glimepiride) | Increased blood-sugar-lowering effect | High — additive hypoglycemia risk | Monitor blood glucose more frequently; dose reduction may be needed |
| ACE inhibitors (e.g. enalapril, ramipril) | May enhance insulin sensitivity | Moderate | Monitor blood glucose when starting or adjusting ACE inhibitor |
| Beta-blockers (e.g. atenolol, metoprolol) | May mask hypoglycemia symptoms | High — can hide warning signs | Increased self-monitoring; educate patient on atypical hypoglycemia signs |
| MAO inhibitors | Enhanced blood-sugar-lowering effect | Moderate to high | Close glucose monitoring; potential insulin dose reduction |
| Corticosteroids (e.g. prednisolone, dexamethasone) | Reduced blood-sugar-lowering effect | High — can cause significant hyperglycemia | Insulin dose increase often required; monitor closely |
| Thiazide diuretics (e.g. hydrochlorothiazide) | Reduced blood-sugar-lowering effect | Moderate | Monitor blood glucose; may need insulin dose adjustment |
| Thyroid hormones (e.g. levothyroxine) | Reduced blood-sugar-lowering effect | Moderate | Monitor blood glucose when thyroid dose changes |
| Oral contraceptives | Reduced blood-sugar-lowering effect | Low to moderate | Monitor blood glucose when starting or stopping |
Alcohol can both increase and decrease blood glucose levels unpredictably. Drinking alcohol while using insulin increases the risk of hypoglycemia, especially if you drink on an empty stomach. Additionally, alcohol can impair your ability to recognise the symptoms of hypoglycemia. If you choose to drink, do so in moderation with food, and monitor your blood glucose closely.
What Is the Correct Dosage of Liprolog Mix25 KwikPen?
The dose of Liprolog Mix25 KwikPen is individualised by your doctor based on your blood glucose levels, meal patterns, and overall diabetes management plan. It is typically injected subcutaneously within 15 minutes before a meal, usually two to three times daily. Never adjust your insulin dose without medical guidance.
There is no universal "standard dose" for Liprolog Mix25 KwikPen. Insulin dosing is highly individual and depends on many factors including your body weight, physical activity level, diet, blood glucose targets, other medications, and the type of diabetes you have. Your doctor, endocrinologist, or diabetes specialist nurse will determine the appropriate starting dose and adjust it over time based on your blood glucose readings.
Adults
Type 2 Diabetes — Adults
Liprolog Mix25 KwikPen is most commonly used in type 2 diabetes as part of a step-up from basal insulin alone when additional mealtime coverage is needed. Typical starting approaches include:
- Twice daily: Injected before breakfast and before the evening meal, with the majority of the daily dose often given in the morning
- Three times daily: Injected before each main meal for patients requiring more intensive coverage
Total daily insulin requirements for adults with type 2 diabetes typically range from 0.5 to 1.0 units per kilogram of body weight per day, though some patients with significant insulin resistance may require higher doses. Your doctor will determine the proportion to be given as Liprolog Mix25.
Type 1 Diabetes — Adults
In type 1 diabetes, Liprolog Mix25 KwikPen may be used as part of a multiple daily injection regimen, although many specialists prefer a basal-bolus approach using separate rapid-acting and long-acting insulins for more precise glucose control. When used, it is typically injected two to three times daily before meals, often in combination with a long-acting basal insulin at bedtime.
Children and Adolescents
Liprolog Mix25 KwikPen may be used in children and adolescents with diabetes on the advice of their paediatric endocrinologist. However, biphasic insulin mixtures are less commonly prescribed in children than in adults because the fixed ratio limits dosing flexibility. Most paediatric guidelines recommend a basal-bolus insulin regimen for growing children and adolescents, as it allows more precise dose adjustments around variable meal sizes and activity levels.
When Liprolog Mix25 is used in younger patients, the dose is calculated based on body weight and blood glucose targets, typically starting at a lower total daily dose and titrating upward. Close monitoring by a specialist paediatric diabetes team is essential.
Elderly Patients
Elderly patients (aged 65 and over) may have altered insulin sensitivity and are at increased risk of hypoglycemia, which can have more serious consequences in older adults, including falls, fractures, and cardiovascular events. Blood glucose targets may be set less stringently in elderly patients to reduce hypoglycemia risk. The starting dose should be conservative, and dose adjustments should be made cautiously with frequent blood glucose monitoring.
Missed Dose
If you miss a dose of Liprolog Mix25 KwikPen before a meal, monitor your blood glucose level. If the meal has already passed, do not inject the missed dose and do not double your next dose to compensate. Instead, continue with your normal injection schedule at the next meal. If you are unsure what to do, contact your doctor or diabetes nurse for advice. Repeated missed doses can lead to poor blood glucose control, so speak with your healthcare team if you are having difficulty with your injection schedule.
Overdose
An overdose of insulin causes hypoglycemia, which can be life-threatening if not treated promptly. Symptoms progress from mild (trembling, sweating, hunger, rapid heartbeat) to severe (confusion, seizures, loss of consciousness).
- Mild hypoglycemia: Eat or drink a fast-acting sugar source immediately (glucose tablets, fruit juice, sugary drink), followed by a slow-release carbohydrate (bread, biscuits, a meal)
- Severe hypoglycemia (unable to treat yourself): Another person should administer glucagon injection and call emergency services. Do not attempt to give food or drink to an unconscious person
After recovering from a severe hypoglycemic episode, contact your doctor. You may need adjustment of your insulin dose, meal plan, or physical activity routine.
What Are the Side Effects of Liprolog Mix25 KwikPen?
The most common side effect of Liprolog Mix25 KwikPen is hypoglycemia (low blood sugar). Other side effects include injection site reactions, lipodystrophy (changes in fat tissue at injection sites), and allergic reactions. Most side effects are manageable with proper technique and monitoring. Contact your doctor if side effects concern you.
Like all medicines, Liprolog Mix25 KwikPen can cause side effects, although not everybody gets them. The frequency of side effects is classified according to international convention as follows:
Very Common
May affect more than 1 in 10 people
- Hypoglycemia (low blood sugar) — symptoms include trembling, sweating, rapid heartbeat, dizziness, hunger, tingling in lips or fingers, pallor, headache, blurred vision, confusion. Severe hypoglycemia can cause seizures and loss of consciousness
Common
May affect up to 1 in 10 people
- Injection site reactions — redness, swelling, itching, or pain at the injection site. These are usually mild and resolve within a few days
- Lipodystrophy — lumps or indentations in the skin at frequently used injection sites due to changes in subcutaneous fat tissue. Prevented by rotating injection sites
- Localised skin reactions — mild rash or irritation around injection sites
Uncommon
May affect up to 1 in 100 people
- Local allergic reactions — more extensive redness, swelling, or itching around the injection site
- Oedema (fluid retention) — swelling of ankles or legs, particularly when starting insulin therapy or after a significant dose increase
- Visual disturbances — temporary blurred vision when starting insulin or with rapid changes in blood glucose control; usually resolves as glucose levels stabilise
Rare
May affect up to 1 in 1,000 people
- Systemic allergic reaction (anaphylaxis) — generalised skin rash, swelling of the face/throat, difficulty breathing, rapid heartbeat, sweating, drop in blood pressure. This is a medical emergency — seek immediate medical help
- Peripheral neuropathy — painful nerve tingling, particularly when blood glucose control improves very rapidly after a period of poor control (treatment-induced neuropathy)
If you experience any serious side effects, or if you notice any side effects not listed here, please contact your doctor, pharmacist, or diabetes nurse. You can also report side effects directly to your national medicines regulatory authority (e.g. the Yellow Card Scheme in the UK, MedWatch in the US, or the EudraVigilance system in the EU).
Rotate your injection sites systematically within each injection area (abdomen, thigh, upper arm, buttocks). Avoid injecting into the same spot repeatedly. If you notice lumps, thickening, or indentations in the skin at injection sites, switch to a different area and inform your doctor. Injecting into lipodystrophic areas can result in unpredictable insulin absorption and poor glucose control.
How Should You Use Liprolog Mix25 KwikPen?
Inject Liprolog Mix25 KwikPen subcutaneously within 15 minutes before a meal. Always re-suspend the insulin by rolling and inverting the pen before each injection. Rotate injection sites to prevent lipodystrophy. Use a new needle for every injection and prime the pen before dialling your dose.
Liprolog Mix25 KwikPen is for subcutaneous injection only — it must never be injected into a vein (intravenous) or into a muscle (intramuscular). The suspension formulation is not suitable for use in insulin pumps. Follow these steps each time you use the pen:
Step-by-Step Injection Guide
- Check the pen: Verify the label says "Liprolog Mix25" and check the expiry date. Do not use an expired pen.
- Re-suspend the insulin: Roll the pen gently between your palms 10 times, then invert it (turn upside down and back) 10 times. The insulin should appear uniformly cloudy or milky white. Do not use if particles or clumps remain, or if the suspension appears clear rather than cloudy.
- Attach a new needle: Peel the paper tab from a sterile pen needle. Screw the needle straight onto the pen until snug. Remove the outer needle cap (keep it for later) and the inner needle cap (discard it).
- Prime the pen: Dial 2 units. Hold the pen with the needle pointing up, tap gently to move any air bubbles to the top, then press the injection button firmly. A stream or drop of insulin should appear at the needle tip. Repeat until insulin appears.
- Select your dose: Turn the dose knob to dial your prescribed number of units. Double-check the number in the dose window.
- Choose and clean the injection site: Suitable areas include the abdomen, front of thighs, upper arms, or buttocks. Clean the skin with an alcohol swab if instructed by your healthcare team.
- Inject: Insert the needle into the skin. Press the injection button all the way in. Keep the button pressed and count slowly to 10 before withdrawing the needle, to ensure the full dose is delivered.
- Remove the needle: Replace the outer needle cap, unscrew the used needle, and dispose of it in a sharps container. Replace the pen cap. Never store the pen with a needle attached.
Rotate your injection site within each area — for example, move to a slightly different spot on your abdomen each time. This prevents lipodystrophy (hard lumps or fat loss under the skin), which can affect insulin absorption. Absorption rates vary between body areas: the abdomen generally provides the fastest and most consistent absorption.
How Should You Store Liprolog Mix25 KwikPen?
Store unused Liprolog Mix25 KwikPen pens in the refrigerator at 2–8°C. Once in use, the pen can be kept at room temperature (below 30°C) for up to 28 days. Do not freeze insulin. Do not use if the insulin has been frozen. Protect from direct heat and sunlight. Discard any pen after 28 days, even if insulin remains.
Proper storage is essential to maintain the effectiveness and safety of your insulin. Insulin that has been stored incorrectly may not work properly, leading to poor blood glucose control. Follow these guidelines:
- Before first use: Store in the refrigerator (2–8°C / 36–46°F). Keep in the original carton to protect from light. Do not freeze — frozen insulin is damaged and must be discarded
- In-use pen: Store at room temperature (below 30°C / 86°F) for a maximum of 28 days. Do not refrigerate the pen you are currently using, as cold insulin can be uncomfortable to inject
- Protect from extremes: Do not expose to direct sunlight, heat sources, or temperatures above 30°C. In hot weather, use an insulated cooling case for transport
- Do not store with a needle attached: This can cause air bubbles, contamination, or insulin leakage
- Before each use: Inspect the insulin suspension after re-suspending. It should appear uniformly cloudy or milky white. Discard the pen if the suspension contains visible particles, clumps, or appears unusually clear
Keep all insulin out of the reach and sight of children. Do not use Liprolog Mix25 KwikPen after the expiry date stated on the label and carton. Dispose of used pens according to your local regulations for medical waste — do not throw them in ordinary household waste.
What Does Liprolog Mix25 KwikPen Contain?
Each millilitre of Liprolog Mix25 KwikPen contains 100 units of insulin lispro as the active substance. The other ingredients include protamine sulfate, metacresol, phenol, glycerol, dibasic sodium phosphate, zinc oxide, hydrochloric acid, sodium hydroxide, and water for injections.
The active substance is insulin lispro, present in two forms in the Mix25 formulation:
- 25% insulin lispro (rapid-acting, dissolved in solution) — this is the clear portion
- 75% insulin lispro protamine suspension (intermediate-acting) — this is the cloudy portion, where insulin lispro is bound to protamine to slow its absorption
The other ingredients (excipients) include:
- Protamine sulfate: Binds to insulin lispro to create the intermediate-acting component
- Metacresol and phenol: Preservatives that prevent microbial growth
- Glycerol: Isotonicity agent that makes the injection comfortable
- Dibasic sodium phosphate: Buffer to maintain stable pH
- Zinc oxide: Stabilises the insulin molecule
- Hydrochloric acid and sodium hydroxide: Used to adjust pH during manufacturing
- Water for injections: The solvent
Liprolog Mix25 KwikPen contains no latex. The pre-filled pen delivers insulin through compatible pen needles (sold separately). Each pen contains 3 mL of suspension, equivalent to 300 units of insulin lispro. The pen allows dose selection in 1-unit increments, with a maximum single dose of 60 units per injection.
Frequently Asked Questions about Liprolog Mix25 KwikPen
Liprolog Mix25 KwikPen is used to treat diabetes mellitus in adults (and some adolescents) who need insulin to control their blood glucose levels. It contains a biphasic mixture of rapid-acting and intermediate-acting insulin lispro, which provides coverage for both mealtime glucose spikes and between-meal blood sugar management. It is suitable for use in both type 1 and type 2 diabetes as part of an individualised insulin regimen prescribed by your doctor.
First, re-suspend the insulin by rolling the pen between your palms 10 times and inverting it 10 times until it appears uniformly cloudy. Attach a new sterile pen needle. Prime the pen by dialling 2 units and pressing the button until insulin appears at the needle tip. Dial your prescribed dose, insert the needle into your chosen injection site (abdomen, thigh, upper arm, or buttocks), press the button fully, and count to 10 before withdrawing. Always inject within 15 minutes before a meal.
If you experience symptoms of hypoglycemia (low blood sugar) such as trembling, sweating, dizziness, hunger, or confusion, immediately consume a fast-acting sugar source: glucose tablets, fruit juice (150 mL), or a sugary drink. Follow this with a slower-release carbohydrate such as a sandwich or biscuits. If the person is unconscious or unable to swallow, do not give food or drink — instead, administer a glucagon injection and call emergency services. Always carry glucose tablets or a sugary snack when using insulin.
Yes, insulin lispro can be used during pregnancy. Good blood glucose control is essential for both the mother and the developing baby. However, insulin requirements change throughout pregnancy — typically decreasing in the first trimester and increasing in the second and third trimesters. Your diabetes specialist will monitor you closely and adjust your doses accordingly. After delivery, insulin needs usually return to pre-pregnancy levels quite quickly. Insulin lispro is also compatible with breastfeeding.
Once you start using a Liprolog Mix25 KwikPen, it can be stored at room temperature (below 30°C / 86°F) for up to 28 days. After 28 days, you must discard the pen even if it still contains insulin, as the preservatives may no longer be fully effective. Unused pens should be stored in the refrigerator (2–8°C). Never freeze the pen, and never use insulin that has been frozen.
Liprolog Mix25 contains 25% rapid-acting insulin lispro and 75% intermediate-acting insulin lispro protamine. Other premixed insulins differ in their ratios and insulin types: for example, Liprolog Mix50 has a 50/50 split, NovoMix 30 contains 30% insulin aspart and 70% insulin aspart protamine, and Humalog Mix25 is essentially identical to Liprolog Mix25 (both contain insulin lispro in the same ratio). The choice depends on your individual glucose profile, meal patterns, and your doctor's assessment of which ratio best suits your needs.
References
All medical information in this article is based on the following peer-reviewed sources and international guidelines:
- European Medicines Agency (EMA). Liprolog — Summary of Product Characteristics (SmPC). Last updated 2024. Available from: www.ema.europa.eu
- American Diabetes Association (ADA). Standards of Care in Diabetes — 2025. Diabetes Care. 2025;48(Suppl 1). doi: 10.2337/dc25-SINT
- World Health Organization (WHO). WHO Model List of Essential Medicines, 23rd List, 2023. Geneva: WHO; 2023.
- Davies MJ, et al. Management of hyperglycemia in type 2 diabetes, 2022: a consensus report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetes Care. 2022;45(11):2753-2786. doi: 10.2337/dci22-0034
- National Institute for Health and Care Excellence (NICE). Type 2 diabetes in adults: management. NICE guideline [NG28]. Updated 2022.
- Eli Lilly and Company. Liprolog Mix25 KwikPen — Patient Information Leaflet. Last revised 2024.
- International Diabetes Federation (IDF). IDF Diabetes Atlas, 10th Edition. Brussels: IDF; 2021.
- Buse JB, et al. 2019 update to: Management of hyperglycemia in type 2 diabetes, 2018. A consensus report by the ADA and EASD. Diabetes Care. 2020;43(2):487-493.
Medical Editorial Team
This article has been written and reviewed by the iMedic Medical Editorial Team, comprising licensed specialist physicians in endocrinology, diabetology, and clinical pharmacology with documented academic backgrounds and clinical experience in diabetes management.
All content is reviewed according to international guidelines (WHO, EMA, ADA, NICE) using the GRADE evidence framework. Evidence level: 1A.
iMedic has no commercial funding. All content is independent of pharmaceutical industry sponsorship or advertising.