Fybogel (ispaghula husk)

NHS Choices

About Fybogel

Fybogel is a laxative taken to treat constipation (difficulty pooing).

It comes as plain or fruit-flavoured granules that you mix with water to make a high-fibre drink.

Fybogel is available on prescription and to buy from pharmacies and supermarkets.

Key facts

Fybogel is a high-fibre drink that you take in the morning and evening, preferably after a meal.
Fybogel takes 2 or 3 days to work.
When taking this type of laxative make sure you drink plenty of fluids.
The main side effects are wind and bloating.
Fybogel is also called ispaghula husk and Ispage.

Who can and can't take Fybogel

Fybogel can be taken by adults including pregnant and breastfeeding women.

Fybogel can be taken by children aged 6 years and older. Do not give Fybogel to a child under 6 years unless your doctor has said it's ok.

Fybogel isn't suitable for everyone. To make sure Fybogel is safe for you, tell your doctor or pharmacist if you have:

had an allergic reaction to Fybogel or any other medicines in the past
a bowel obstruction
muscle weakness of the bowel (colonic atony)
a rare genetic illness called phenylketonuria

How and when to take it

Fybogel comes as sachets of plain, orange or lemon-flavoured granules. It's best to take Fybogel after a meal or snack.

How much should I take?

The normal dose for constipation in:

adults and children aged 13 years and over is 1 sachet of Fybogel granules twice a day
children aged 6 to 12 years is ½ to 1 level 5ml spoonful of Fybogel granules twice a day
children under the age of 6 years (only under medical supervision) is ½ to 1 level 5ml spoonful of Fybogel granules twice a day

How to take it

To make up the medicine, open the sachet and empty the granules into a glass. Add at least 150mls (1/4 pint) of cold water to the glass. Stir well until all the granules have dissolved and the Fybogel solution is clear or slightly hazy, and then drink it straight away.

Try not to breathe in the powder when you make up the Fybogel drink as it can occasionally trigger a mild allergic reaction.

Have your evening drink of Fybogel at least an hour before going to bed. Drinking Fybogel just before you go to sleep increases the chances of it causing a blockage in the gut.

Aim to drink 6 to 8 glasses of fluid during the day while you are taking Fybogel or the constipation may get worse.

What if I forget to take it?

If you forget a dose of Fybogel, don't worry, just take the next dose at the usual time.

Never take 2 doses at the same time. Never take an extra dose to make up for a forgotten one.

What if I take too much?

Taking too much Fybogel by accident is unlikely to harm you. If this happens, drink plenty of water.

If you're worried, talk to your doctor or pharmacist for advice.

Side effects

Like all medicines, Fybogel may cause side effects in some people, but many people have no side effects or only minor ones.

Common side effects

The most common side effects, which happen in more than 1 in 100 people, are wind and bloating. This sometimes happens because of the sudden increase of fibre in your diet. It should get better after a few days.

If the side effects carry on, or if you are worried, talk to your doctor or pharmacist.

Mild allergic reaction

It's possible to have a mild allergic reaction such as itchy eyes, nose or skin.

You're more likely to have a mild allergic reaction to Fybogel if you've had an allergic reaction before and if you're exposed to the powder regularly, for example if you're a carer.

If you think you are having a mild allergic reaction to Fybogel, stop taking it and ask your pharmacist or doctor for advice.

Serious allergic reaction

In rare cases, it’s possible to have a serious allergic reaction to Fybogel.

A serious allergic reaction is an emergency. Contact a doctor straight away if you think you or someone around you is having a serious allergic reaction.

The warning signs of a serious allergic reaction are:

getting a skin rash that may include itchy, red, swollen, blistered or peeling skin
wheezing
tightness in the chest or throat
having trouble breathing or talking
swelling of the mouth, face, lips, tongue, or throat

These are not all the side effects of Fybogel. For a full list see the leaflet inside your medicines packet.

You can report any suspected side effect to the UK safety scheme.

Pregnancy and breastfeeding

Fybogel is generally safe to take during pregnancy and while breastfeeding.

For safety, tell your pharmacist or doctor if you're trying to get pregnant, are already pregnant or if you're breastfeeding.

Cautions with other medicines

Fybogel can change the way some medicines work. Tell your doctor if you are taking these medicines before starting Fybogel:

carbamazepine (a medicine for epilepsy and mood problems)
digoxin (a heart medicine)
mesalazine (a medicine to treat gut problems)

There is some evidence that Fybogel stops iron being taken in properly by the body. If you need iron supplements, it's best to take them at least 1 hour before, or 4 hours after, you take Fybogel.

Mixing Fybogel with herbal remedies and supplements

There are no known problems with taking herbal remedies and supplements with Fybogel.

However, for safety, tell your doctor or pharmacist if you're taking any other medicines, including herbal remedies, vitamins or supplements.

Common questions

How does Fybogel work?

Fybogel is called a bulk laxative. It helps to bulk up poo with fluid so it's softer and easier to pass.

When will I feel better?

It takes 2 to 3 days for Fybogel to work.

Talk to your doctor if you are still constipated after 3 days.

How long will I take Fybogel for?

You can take Fybogel for as long as the constipation lasts, or for as long as your doctor has recommended. This will usually be for up to a week.

For more serious constipation, and if you are taking Fybogel to increase the fibre in your diet, your doctor may recommend that you take it for many months.

Is it safe to take Fybogel for a long time?

Ideally, you should only use Fybogel occasionally and for a few days at a time.

Using laxatives like Fybogel for longer can lead to prolonged diarrhoea. It can also cause an electrolyte imbalance. This is where levels of substances like sodium, potassium and magnesium in your body get too high or too low. A severe electrolyte imbalance can cause serious health problems such as muscle spasm and twitching and even convulsions.

However, there are some situations where you may need to take Fybogel for many months, for instance if you need to increase the fibre in your diet. Your doctor will decide exactly how long and how much Fybogel you need to take.

Can I take different laxatives together?

For most people, one laxative will be enough to relieve constipation.

Occasionally, you may need to take 2 different types of laxatives at the same time to get your bowels moving again. Only take 2 laxatives together on the advice of your doctor or pharmacist as there's an increased risk of side effects.

Are other laxatives any better?

There are other types of laxatives. They work in a different way to Fybogel but are equally good at treating constipation. Some may work more quickly than Fybogel.

Osmotic laxatives, for example lactulose. These draw water from the rest of the body into your bowel to soften poo and make it easier to pass. They take 2 or 3 days to work.
Stimulant laxatives, for example senna and bisacodyl. These speed up your bowels by stimulating the nerves that control the muscles lining your gut. They work more quickly than other laxatives. If you take them at bedtime, they work overnight.
Surface-wetting laxatives, for example arachis oil and docusate sodium. These allow water to get into poo to soften it and make it easier to pass.

Can I take it with IBS remedies?

You can take Fybogel alongside IBS remedies such as Buscopan.

Can I take Fybogel after an operation?

Yes, you can take Fybogel to relieve constipation after surgery.

Is there any food or drink I need to avoid?

You can eat and drink normally while taking Fybogel.

It might help to stop eating pastries, puddings, sweets, cheese and cake for a while as these foods can make constipation worse.

Can I drink alcohol with it?

Yes, you can drink alcohol with Fybogel.

Can lifestyle changes help constipation?

It's often possible to relieve constipation without having to use laxatives. Before trying Fybogel - or to stop constipation coming back - it may help to:

eat more fibre - aim for about 30g of fibre a day. High-fibre foods include fruit, vegetables and cereals. If you are not used to a high-fibre diet, it may be best to increase the amount of fibre you eat gradually
add bulking agents, such as wheat bran, to your diet - these will help make your poo softer and easier to pass (although bran and fibre can sometimes make bloating worse)
drink plenty of water - to keep poo soft
exercise regularly - keeping your body active will help to keep your gut moving