PERT – getting pancreatic enzyme replacement right (a practical guide)

For patients, families, and primary care teams. From the team behind prehabforsurgery.com.

If you have had pancreatic surgery, or if you live with chronic pancreatitis, cystic fibrosis, or pancreatic cancer, there is a good chance you have been prescribed pancreatic enzyme replacement therapy — PERT for short. The most commonly prescribed brand in Ireland and the UK is Creon, but Nutrizym and Pancrex are also in use, and other brands exist in other countries. They all do essentially the same job: replace the digestive enzymes that your pancreas would normally produce but no longer can.

PERT works very well when it is taken properly. When it is not – and many people get one or more of the basics wrong, often through no fault of their own because the instructions are often unclear – it works much less well, or not at all. This article is a practical guide to getting PERT right. It is not a substitute for advice from your pancreatic team or dietitian, but it is a starting point for the conversations that follow.

What PERT does and why you need it

The pancreas has two jobs. The first – making insulin and glucagon to control blood sugar – is the endocrine job, and damage to it leads to diabetes. The second is the exocrine job: making the digestive enzymes that break down food. The three main classes are lipase (breaks down fats), amylase (carbohydrates), and protease (proteins). These enzymes are released into the gut at every meal to mix with food and break it down so the nutrients can be absorbed.

When the pancreas is damaged, removed in part or in full, scarred by chronic inflammation, or invaded by a tumour, exocrine function falls. The result is pancreatic exocrine insufficiency (PEI). Symptoms include weight loss, fatty foul-smelling hard-to-flush stools (steatorrhoea), bloating, abdominal cramps after meals, and fat-soluble vitamin deficiencies (A, D, E, K). Left untreated, PEI causes malnutrition, osteoporosis, and a reduced quality of life – even when the underlying pancreatic condition is otherwise stable.

PERT replaces those missing enzymes by giving you capsules that contain the same digestive enzymes – extracted (in the case of Creon, Nutrizym, and Pancrex) from porcine pancreas. The capsules are designed to release the enzymes in the right part of the gut at the right pH so they can do their job. When the timing and dose are correct, PERT restores most or all of the normal digestion of fats and proteins.

Who needs PERT?

The main conditions in which PERT is routinely prescribed:

• Chronic pancreatitis – most patients eventually develop exocrine insufficiency and benefit from PERT

• Pancreatic cancer – exocrine insufficiency is very common, often present at diagnosis even before any surgery

• After Whipple’s procedure (pancreaticoduodenectomy) – most patients need at least some PERT, often lifelong

• After distal pancreatectomy – variable but commonly needed

• After total pancreatectomy – always required, lifelong, no exceptions

• Cystic fibrosis — universal need from early life

• Acute pancreatitis with significant tissue loss – PERT may be needed temporarily or long-term

• Severe coeliac disease, Crohn’s disease, and some other conditions – PERT is sometimes considered if there is co-existent exocrine dysfunction

If you have any of these conditions and have symptoms suggestive of malabsorption –  particularly unexplained weight loss, ongoing steatorrhoea, bloating, or low fat-soluble vitamin levels on blood tests – ask your team whether PERT should be initiated or whether your dose should be reviewed.

The brands – what’s actually in the capsules

All current first-line PERT products in Ireland and the UK are extracted from porcine (pig) pancreas. The active ingredient is called pancrelipase (also spelled pancreatipase, or just called pancreatic enzymes). Brand names differ; the doses differ; the formulation principles are similar.

• Creon – by far the most commonly prescribed in Ireland and the UK. Available in 10,000, 25,000, and 40,000 lipase-unit capsules. Enteric-coated mini-microspheres designed to release in the duodenum at the right pH.

• Nutrizym 22 – alternative formulation, 22,000 lipase units per capsule. Similar concept.

• Pancrex V – older formulation, available as capsules, powder, or granules. Lower-dose options can be useful for paediatric and small-dose use.

• Other brands available in other countries (Zenpep, Pertzye, Viokace in the US; brand names vary in continental Europe).

If you are switching between brands – sometimes due to supply shortages-— note that dose equivalence is not exactly 1:1. Your team should review the dose conversion. Do not self-substitute one brand for another at the same capsule count.

The single most important rule – timing

If you take only one piece of advice from this article, take this one: PERT capsules need to be in your stomach AT THE SAME TIME as the food they are meant to digest.

Specifically:

• Take the first capsule (or capsules) with the FIRST bite of the meal – not 10 minutes before, not after the meal is finished

• For a meal lasting longer than 20-30 minutes, SPLIT the dose – take some at the start, some halfway through

• If you forget at the start of the meal, take the capsule(s) as soon as you remember during the meal – better late than not at all

• If you remember only after the meal is finished, taking the dose then will not help – the food has already moved through the stomach without enzyme cover

Why does timing matter so much? The capsules are designed to dissolve in the duodenum (the first part of the small intestine, just past the stomach) and release the enzymes there, mixed with the food being passed through. If the enzymes arrive too early, they pass through without food to act on. If they arrive too late, the food has already moved further down the gut where there is nothing to digest with them. Either way, the dose is wasted.

How much to take – general principles

Specific doses must be decided by your pancreatic team or dietitian – they take into account your weight, the severity of your exocrine insufficiency, the typical fat content of your meals, your symptoms, and your response to current dose. The following are general principles drawn from established guidance (UEG, BSG, ESPEN), not personal advice:

• Most adults with exocrine insufficiency from chronic pancreatitis or pancreatic cancer start on 40,000–50,000 lipase units per main meal, with 10,000-25,000 units per snack

• Post-total-pancreatectomy patients often need higher doses – 50,000–75,000 units per main meal is common

• Doses can be titrated up if symptoms persist – there is no fixed upper limit for adults, although the cumulative daily dose should not exceed roughly 10,000 lipase units per kilogram of body weight per day, or 4,000 lipase units per gram of dietary fat (per BSG and US FDA labelling, to reduce theoretical risk of fibrosing colonopathy at very high doses in children – relevant mainly in cystic fibrosis paediatric practice)

• The dose for a snack scales with what the snack contains – small low-fat snack (an apple) may need no PERT; larger snacks containing fat or protein typically need 25,000 units or so

• Liquid meals (smoothies, soups) still need PERT – fat content matters more than texture

If your symptoms are not controlled on the current dose — particularly continued steatorrhoea, weight loss, or fat-soluble vitamin deficiency on blood tests — the answer is usually to increase the dose (or improve the timing), NOT to restrict your diet further. Restricting fat removes calories without solving the underlying problem.

Common mistakes that reduce PERT effectiveness

Most patients, even years into treatment, are getting at least one of the following wrong. Working through this list with your dietitian is often the single biggest yield in symptom control.

1. Wrong timing

Covered above – capsules need to be in the stomach with the food. Taking them all at the end of the meal is a common mistake.

2. Chewing the capsules or breaking them open

Do not chew. The enteric coating on the microspheres is what allows the enzymes to survive stomach acid and reach the duodenum intact. Chewed capsules release enzymes prematurely in the mouth and stomach, where they are destroyed by stomach acid. If swallowing whole is difficult, open the capsule onto a small amount of cold, soft, slightly acidic food (apple sauce works well) – do NOT mix with anything hot, alkaline, or dairy.

3. Hot drinks or alkaline foods

Do not take PERT with very hot drinks. Heat damages the enteric coating before the capsule even reaches the stomach. Do not take with very alkaline food (some dairy, antacids) – alkaline environments also break the coating.

4. Skipping snacks

People remember PERT for main meals but skip snacks. A snack containing fat or protein needs PERT too. Crisps, biscuits, a slice of cheese, a glass of milk – all need at least a small dose. Routine skipping leads to persistent malabsorption even when main meals are well-covered.

5. Stopping when symptoms improve

Some patients stop or reduce PERT when symptoms get better, thinking they no longer need it. The symptoms improved BECAUSE of the PERT – stopping it will bring them back, often weeks later when fat-soluble vitamin stores are also depleted. PERT for most causes (chronic pancreatitis, post-total-pancreatectomy, cystic fibrosis) is lifelong.

6. Sub-optimal dose due to medication shortage substitution

Recent supply disruptions of Creon have meant some patients have been switched to alternative brands or strengths. The dose conversion between brands is not always exact. If you have been switched, your symptoms or stool pattern may change – ask for a dose review.

7. Storing PERT badly

Heat damages PERT. Do not leave capsules in a hot car, on a sunny windowsill, or in checked luggage on a flight. Always carry PERT in hand luggage when travelling. Store at room temperature, away from heat sources. If capsules look discoloured or the coating is sticky, ask your pharmacist for replacement.

8. Travel without backup

Always travel with extra PERT – at least double the days of supply you expect to need. Lost luggage, delayed flights, or a longer trip mean days without PERT, which can take weeks of malabsorption to recover from. Hand luggage only. Consider a doctor’s letter for customs if travelling internationally with large quantities.

Special situations

Snacks and small meals

Carry a smaller-dose pack (10,000 or 25,000 unit capsules) for snacks. A handbag-sized pillbox helps. Aim never to eat anything containing fat or protein without PERT cover.

Long meals (restaurants, family gatherings)

Take half the dose at the start, half halfway through. Three-hour family dinners are real and your enzymes will be exhausted before the dessert if you took them all at the start.

Illness – particularly vomiting or diarrhoea

If you are vomiting and the PERT capsule comes back up, that dose is lost — re-dose when you can keep food down. Severe diarrhoea may reflect malabsorption from inadequate PERT dose, OR an unrelated cause (infection, medication side effect). If diarrhoea is persistent for more than 24 hours, contact your team.

Surgery, procedures, fasting periods

During a fast (no food) you do not need PERT – enzymes have nothing to digest. As soon as food is reintroduced, restart PERT at the same dose as before unless your team advises otherwise.

Pregnancy and breastfeeding

PERT is considered safe in pregnancy and breastfeeding. Doses may need adjusting upwards to meet increased calorie demand. Discuss with your team early in pregnancy.

Signs your PERT dose is not right

• Steatorrhoea – fatty, foul-smelling, oily, hard-to-flush stools

• Unexplained weight loss despite eating normally

• Persistent bloating, cramps, or abdominal pain after meals

• Excessive flatulence or burping after eating

• Low levels of fat-soluble vitamins (A, D, E, K) on annual blood tests

• Low bone density on DEXA scans – long-term untreated PEI causes osteoporosis

• New onset or worsening of diabetes control in patients with type 3c diabetes – poor PERT timing and dosing makes carb absorption unpredictable, which destabilises blood sugar

Any of these is a reason to ask for a PERT review. The fix is usually a higher dose, better timing, or both – rarely a stricter diet.

A practical daily routine that works for most people

• Breakfast – PERT capsules at the first bite. Same with morning coffee/tea if it contains milk.

• Mid-morning snack – small PERT dose with any fat- or protein-containing snack.

• Lunch – PERT capsules at the first bite. Split the dose if lunch will last more than 20 minutes.

• Afternoon snack – small dose if needed.

• Dinner – PERT capsules at the first bite. Split dose for longer meals.

• Evening snack – small dose if needed.

• Travel days – extra supply in hand luggage. Pillbox of mixed doses for unpredictable meal sizes.

Resources and where to find more help

• Your pancreatic surgical team or hepatobiliary clinic – first point of call for dose reviews

• Your dietitian – typically the best person to fine-tune PERT timing and dosing

• Pancreatic Cancer UK – pancreaticcancer.org.uk – has practical guides on PERT and post-surgical nutrition

• National Pancreas Foundation (US) – pancreasfoundation.org – chronic pancreatitis and post-surgical resources

• Mission: Cure – mission-cure.org – particularly active community for chronic pancreatitis patients

• Cystic Fibrosis Trust (UK) / Cystic Fibrosis Foundation (US) – long-established guidance on PERT for CF, much of which translates well to other PEI causes

• Creon, Nutrizym, and Pancrex product information leaflets – useful for brand-specific dosing tables, available on each manufacturer’s website.

A final word

PERT is one of the genuinely successful chronic-condition treatments of the last fifty years. When it is used properly it transforms quality of life for people with pancreatic exocrine insufficiency. When it is used incorrectly – and the most common pitfalls are timing, snacks, and stopping when symptoms improve – much of that benefit is lost.

If you take nothing else from this article, take this: PERT with the first bite of every meal and every snack containing fat or protein, for life. Get a dose review with your team or dietitian if symptoms are not well controlled. Carry extra PERT when travelling. And do not stop, even when you feel well – the feeling well IS the PERT working.

Evidence base

Key sources informing this article:

• Domínguez-Muñoz JE et al. Recommendations from the United European Gastroenterology evidence-based guidelines for the diagnosis and therapy of chronic pancreatitis. United European Gastroenterol J 2017;5(2):153–199.

• Phillips ME et al. Consensus for the management of pancreatic exocrine insufficiency: UK practical guidelines. BMJ Open Gastroenterology 2021;8:e000643.

• Lindkvist B et al. Clinical, anthropometric and laboratory nutritional markers of pancreatic exocrine insufficiency: prevalence and diagnostic use. Pancreatology 2015;15(6):589–597.

• Sikkens ECM, Cahen DL et al. The daily practice of pancreatic enzyme replacement therapy in chronic pancreatitis: a Northern European survey. United European Gastroenterol J 2012.

• NICE Guideline NG104 — Pancreatitis (2018, updated 2024) — UK national guidance including PERT recommendations.

• ESPEN guideline on clinical nutrition in acute and chronic pancreatitis. Clin Nutr 2020;39(3):612–631.

Reviewed by Mr Tom Gallagher, Consultant HPB Surgeon, St Vincent’s Healthcare Group, Dublin. Last updated 26 May 2026.