Insulin Aspart (NovoRapid, Fiasp, Trurapi)

Insulin aspart is a rapid-acting insulin analogue used to treat diabetes. It is usually taken around mealtimes to control blood sugar spikes, alongside a longer-acting "basal" insulin. In the UK it is available under the brand names NovoRapid, Fiasp and the biosimilar Trurapi.

This article is for information only. It is not medical advice. If you need help with your insulin, speak to your pharmacist, GP or diabetes team. In an emergency, call 999.

Current UK Insulin Aspart Supply Status

What to do if your usual insulin is unavailable

• Do not stop taking insulin. Stopping insulin can cause diabetic ketoacidosis (DKA), which can be life-threatening.
• Do not borrow insulin, ration doses, stretch supplies, reuse old prescriptions, or change devices or brands without speaking to your pharmacist, prescriber or diabetes team.
• Contact your pharmacist, GP or diabetes specialist as soon as possible if your usual pen or cartridge is out of stock.
• If you are running low and cannot obtain insulin, or you have vomiting, ketones, or symptoms of DKA, seek urgent medical help. Use NHS 111 when it is urgent but not life-threatening. Call 999 for severe hypoglycaemia (unconsciousness, convulsions), suspected DKA with severe symptoms, or a severe allergic reaction.
• Pump users: any pump supply interruption or device change should be handled with your diabetes team because delivery changes can be clinically significant.

What Is Insulin Aspart Used For?

Insulin aspart is used to treat diabetes mellitus in adults, adolescents and children aged 1 year and above. It is a rapid-acting "bolus" or "mealtime" insulin, meaning it is taken to control the rise in blood glucose that happens after eating.

It is normally used together with an intermediate-acting or long-acting insulin that provides background coverage through the day and night. Some people also use it in an insulin pump for continuous subcutaneous insulin infusion.

*Source: NovoRapid SmPC section 4.1*

How It Works

Insulin aspart is a man-made insulin that is very similar to the insulin your body makes, but it is absorbed faster after an injection. This means it starts working more quickly than soluble human insulin.

• Onset of action: 10–20 minutes after injection
• Maximum effect: 1–3 hours after injection
• Duration of action: 3–5 hours

Because it acts quickly, it should generally be taken immediately before a meal. If necessary it can also be taken soon after a meal. It helps glucose move from the bloodstream into cells, where it is used for energy, thereby lowering blood sugar levels.

*Sources: NovoRapid SmPC section 4.2, EMA EPAR for NovoRapid*

Forms and Strengths Available in the UK

All rapid-acting insulin aspart products in the UK are 100 units/ml clear, colourless solutions for injection. They come in several device types:

Fiasp is a faster-acting formulation of insulin aspart that also contains niacinamide. According to its SmPC, it can be taken up to 2 minutes before a meal, or up to 20 minutes after starting a meal if needed.

NovoMix 30 is a separate pre-mixed biphasic insulin that contains 30% insulin aspart and 70% insulin aspart protamine. It is a suspension (not a clear solution) and is used differently from rapid-acting insulin aspart alone.

*Sources: eMC search results, NovoRapid SmPC section 2, Fiasp SmPC section 4.2*

Brand and Generic Names

• NovoRapid (Novo Nordisk) — the original brand
• Fiasp (Novo Nordisk) — faster-acting version
• Trurapi (Sanofi) — a biosimilar insulin aspart
• NovoMix 30 (Novo Nordisk) — a pre-mixed biphasic insulin containing insulin aspart and insulin aspart protamine

*Source: eMC search results*

Invention and Approval History

Insulin aspart was developed by Novo Nordisk A/S in Denmark. The European Medicines Agency's Committee for Medicinal Products for Human Use adopted a positive opinion on 20 May 1999, and the European Commission granted a marketing authorisation valid throughout the EU on 7 September 1999.

Since then, further presentations and the faster-acting Fiasp formulation have been introduced. The biosimilar Trurapi received authorisation more recently.

*Source: EMA EPAR for NovoRapid*

How Insulin Aspart Is Made

Insulin aspart is produced using recombinant DNA technology:

• NovoRapid and Fiasp are produced in *Saccharomyces cerevisiae* (baker's yeast).
• Trurapi is produced in *Escherichia coli* (E. coli) bacteria.

In both cases, the insulin gene is modified so the yeast or bacteria produce insulin aspart, which differs from natural human insulin by one amino acid. This single change makes the insulin molecule form hexamers less readily after injection, allowing it to be absorbed faster into the bloodstream.

*Sources: NovoRapid SmPC section 2, Trurapi SmPC section 2*

Common Side Effects

The most common side effect is hypoglycaemia (low blood sugar), which may affect more than 1 in 10 people. Signs include cold sweat, cool pale skin, headache, rapid heartbeat, feeling hungry, tremor, anxiety, confusion, drowsiness and vision changes.

Other side effects include:

• Injection site reactions — pain, redness, itching, bruising or swelling (usually mild and short-lived)
• Lipodystrophy — fatty tissue may shrink (lipoatrophy) or thicken (lipohypertrophy) under the skin if you inject in the same place repeatedly
• Cutaneous amyloidosis — protein build-up causing lumps under the skin (frequency not known)
• Vision changes — usually temporary when starting insulin
• Swelling around joints (oedema) — usually temporary

*Sources: NovoRapid SmPC section 4.8, NovoRapid PIL*

Serious Side Effects and When to Get Urgent Help

Severe hypoglycaemia can lead to unconsciousness, convulsions, temporary or permanent brain damage, and even death if not treated. If someone with diabetes becomes unconscious from low blood sugar, place them in the recovery position and call 999 immediately. Do not give food or drink by mouth.

Diabetic ketoacidosis can occur if insulin doses are missed or stopped, especially in type 1 diabetes. Warning signs include thirst, frequent urination, nausea, vomiting, drowsiness, flushed dry skin, dry mouth, loss of appetite and a smell of acetone on the breath. This is a medical emergency — seek urgent help.

Serious allergic reactions (anaphylaxis) are very rare (less than 1 in 10,000 people) but potentially life-threatening. Call 999 if you experience spreading rash, difficulty breathing, rapid heartbeat, severe dizziness or vomiting after an injection.

*Sources: NovoRapid SmPC sections 4.4, 4.8, 4.9, NovoRapid PIL*

Interactions and Cautions

Some medicines can raise or lower your blood sugar, meaning your insulin dose may need adjusting. Do not start or stop any medicine without discussing it with your clinician.

Medicines that may reduce your insulin need (risk of hypoglycaemia):

• Other diabetes medicines
• MAOIs (for depression)
• Beta-blockers (for blood pressure)
• ACE inhibitors
• Salicylates (e.g. aspirin)
• Anabolic steroids
• Sulphonamides (antibiotics)

Medicines that may increase your insulin need (risk of high blood sugar):

• Oral contraceptives
• Thiazide diuretics
• Glucocorticoids ("steroids")
• Thyroid hormones
• Sympathomimetics (e.g. salbutamol)
• Growth hormone
• Danazol

Other important cautions:

• Beta-blockers can mask the warning symptoms of low blood sugar.
• Alcohol can either raise or lower blood sugar unpredictably.
• Pioglitazone (a type 2 diabetes tablet) combined with insulin has been linked to heart failure in some patients.
• Octreotide/lanreotide may either increase or decrease insulin requirements.

*Source: NovoRapid SmPC sections 4.4, 4.5*

Pregnancy, Breastfeeding, Driving and Alcohol

Pregnancy: Insulin aspart can be used during pregnancy. Data from clinical trials in over 340 pregnancies showed no adverse effects compared with human insulin. Insulin requirements usually fall in the first trimester, rise during the second and third, and return quickly after delivery. Tight blood glucose control is important. If you are pregnant or planning pregnancy, speak to your diabetes or maternity team.

Breastfeeding: There are no restrictions on using insulin aspart while breastfeeding. It presents no risk to the baby, but your dose may need adjustment. Discuss with your clinician.

Driving: Low blood sugar can impair concentration and reaction times. Take precautions to avoid hypoglycaemia before driving. If you have frequent episodes or reduced awareness of warning symptoms, check DVLA and NHS guidance or speak to your diabetes team. Carry fast-acting glucose in the car.

Alcohol: Drinking alcohol can affect blood sugar unpredictably. Careful monitoring is recommended.

*Sources: NovoRapid SmPC sections 4.6, 4.7, Fiasp SmPC sections 4.6, 4.7, Trurapi SmPC sections 4.6, 4.7, NovoRapid PIL*

Missed Doses and Stopping Suddenly

Missed mealtime dose: If you forget a mealtime dose, monitor your blood glucose level. Resume your usual dosing schedule at the next meal. Do not take a double dose unless your clinician has given you a specific sick-day or correction plan.

Do not stop insulin suddenly: Stopping insulin without medical advice can cause very high blood sugar and diabetic ketoacidosis, which can be life-threatening. If you are struggling to obtain your usual insulin, contact your GP, diabetes specialist or pharmacist immediately.

*Sources: Fiasp SmPC section 4.2, NovoRapid PIL*

Monitoring and Check-Ups

Regular monitoring is essential for safe insulin use:

• Blood glucose testing — as advised by your diabetes team, especially when changing dose, during illness, or when starting a new medicine.
• HbA1c — a long-term blood sugar check, usually every 3–6 months.
• Injection sites — check for lumps, thickening or shrinking of fatty tissue. Rotate injection sites within the same body area (abdomen, thigh, upper arm) to reduce lipodystrophy and cutaneous amyloidosis.
• Weight, blood pressure and foot checks — part of routine diabetes reviews.
• More frequent monitoring is needed during pregnancy, if you have kidney or liver problems, during illness, with increased exercise, or when travelling across time zones.

*Sources: NICE NG28, NovoRapid SmPC sections 4.2, 4.4, Fiasp SmPC section 4.4*

What to Ask a Pharmacist or GP During Supply Issues

If your usual insulin aspart pen or cartridge is unavailable, ask:

1. Which presentations are currently in stock? (e.g. FlexPen vs Penfill vs vial)
2. Can I switch to a biosimilar such as Trurapi? NICE guidance supports shared decision-making when switching to a lower-cost biosimilar.
3. Do I need a new prescription or device training? Different pens and cartridges require different needles or reusable pens.
4. Should my dose change? When transferring between insulin types or brands, your clinician may need to adjust the dose and monitor you more closely.
5. What should I do if my pump cartridge is unavailable? Ask about interim options with your diabetes team, such as self-filling pump reservoirs from vials or switching to injections temporarily.

*Sources: CPE MSNs, NICE NG28 sections 1.34.1, 1.35.4*

Related Medicines a Clinician May Discuss

If insulin aspart is unavailable or unsuitable, your clinician may discuss:

• Other rapid-acting insulin analogues — insulin lispro, insulin glulisine
• Human soluble insulin — taken 30 minutes before meals
• Pre-mixed (biphasic) insulins — NovoMix 30, Humalog Mix25, Humulin M3
• Basal (long-acting) insulins — insulin glargine, insulin detemir, insulin degludec
• Non-insulin medicines for type 2 diabetes — metformin, SGLT2 inhibitors, GLP-1 receptor agonists

Your diabetes team will choose the best option based on your type of diabetes, lifestyle, HbA1c targets and any other health conditions.

*Sources: NICE NG28, NovoRapid SmPC section 4.2*

Frequently Asked Questions

Is there an insulin aspart shortage in the UK?

Specific presentations have been discontinued or are in limited supply. Fiasp FlexTouch and NovoRapid FlexTouch pre-filled pens have been discontinued. NovoRapid PumpCart is in limited supply until 2027. Other presentations such as NovoRapid FlexPen, Penfill, vials, Fiasp Penfill and Trurapi were listed by CPE as able to support demand. Confirm local availability with your pharmacist.

What should I do if my pharmacy cannot get NovoRapid or Fiasp?

Do not stop insulin. Ask your pharmacist which presentations are in stock. Speak to your GP or diabetes team about alternatives such as a different pen, cartridge, vial or biosimilar. Do not change brands or devices without guidance.

Can a pharmacist switch my insulin brand?

A pharmacist cannot change your prescription. They can advise you on what is in stock and may contact your prescriber to discuss alternatives. Any switch should be agreed with your prescriber or diabetes team, with monitoring.

Is NovoRapid FlexTouch discontinued?

Yes. NovoRapid FlexTouch 3 ml pre-filled pens were discontinued from March 2025. NovoRapid FlexPen and Penfill remain listed as available.

What should pump users do if PumpCart is unavailable?

Pump users should contact their diabetes team urgently. Options may include self-filling pump reservoirs from vials or temporary switching to injections. Do not make pump changes without clinical guidance.

Official Sources and Correction Route

This article is based on:

• CPE Medicine Supply Notifications — MSN/2024/027U, MSN/2024/103, MSN/2025/034
• eMC Summary of Product Characteristics — NovoRapid, Fiasp, Trurapi
• eMC Patient Information Leaflet — NovoRapid PIL
• EMA European Public Assessment Report — NovoRapid EPAR
• NICE Guideline NG28 — Type 2 diabetes in adults: management (updated February 2026)

If you suspect a side effect, report it via the MHRA Yellow Card scheme: https://yellowcard.mhra.gov.uk or search "MHRA Yellow Card" in your app store.

If you spot an error in this article, please contact MedWatch UK so we can correct it.

*Last reviewed: 13 May 2026. MedWatch editorial review completed. Clinical reviewer pending. This article is not medical advice.*