Most over the counter laxatives in the UK are available without a prescription. There are four main classes of laxatives that patients can use to manage constipation. Over the counter laxatives (UK) are licensed as General Sale List Products (GSL), available in any retail outlet including pharmacies, and Pharmacy Only medicines (P), which can only be purchased from registered pharmacies, including online chemists. Within each class, over the counter laxatives have specific licensed age restrictions with some available for children only on prescription.
In this post, I will discuss over the counter laxatives commonly used in the UK. In relation to each class, the following will be discussed:
- Classification of over the counter laxatives
- Age restrictions
- Mechanism of action
- Times it takes to work
- Possible side effect
Always read the product information leaflet for detailed use or follow prescriber instructions on use and dosage.
What causes constipation (video)?
Over the counter laxatives UK classification
The most common laxatives belong to one of the following groups:
- Osmotic laxatives
- Bulk-forming laxatives
- Stimulant (Irritant)
- Faecal softeners
Which laxative works the fastest?
Stimulant laxatives and enemas are the fastest in relieving symptoms of constipation. When stimulant laxative is used in the form of suppositories (glycerin suppositories or bisacodyl suppositories), the onset of action (the time it takes to work) is between 10-30 minutes. Bisacodyl or senna tablets can be taken at night to give relief in the morning.
Enemas can start to work in just 5 minutes after the administration.
Which over the counter laxative to choose first?
There is no set rule on which laxative to use first. In many cases changing a diet, particularly increasing fluid intake and increasing fibre (fruit and vegetables) in diet, can have the desired effect. An adult should aim to have around 30g of fibre per day (NICE, 2019). If one produces a hard poo, an osmotic laxative may be a good option. If the poo is soft, a stimulant laxative may be preferred. Another option to consider is the likelihood of side effects (for example, stimulant laxatives are harsher on the stomach than osmotic or bulk-forming laxatives).
Over the counter laxatives: Osmotic laxatives
Mechanism of action
Osmotic laxatives work by introducing more water into the bowel from the body, which in turn has a ‘softening’ effect on the stool, which is easier to pass.
How long do osmotic laxatives take to work?
Osmotic laxatives generally take 1+ days to work. The exact times may vary between different osmotic laxatives and the initial dose taken. It may take 2-3 days for a full laxative effect to take place.
Osmotic laxatives: common side effects
Osmotic laxatives can cause side effects; however, frequency is not determined. Some side effects may include:
- Gastrointestinal side effects such as diarrhoea, vomiting, nausea, abdominal pain
- Allergic reactions including skin reactions or even anaphylactic reactions are also possible
What are the most popular osmotic laxatives?
Most common osmotic laxatives prescribed and purchased over the counter are:
- Macrogols containing products (such as macrogol 3350), for example, Movicol, CosmoCol, and Laxido.
Lactulose is licensed as P medicine, available only from a pharmacy. Lactulose is a form of sugar, which is not absorbed when ingested. Lactulose comes in the form of liquid, which tastes sweet. Lactulose is a popular laxative choice as it is a ‘gentle‘ type of laxative. Lactulose is licensed in infants under one year of age. Although available on Amazon.co.uk, lactulose is available in most pharmacies.
Can lactulose be used in pregnancy?
Lactulose can be used in pregnancy.
Lactulose: main side effects
A very common side effect associated with lactulose use is diarrhoea. Common side effects include:
- Nausea, vomiting
- Abdominal pain (usually with higher doses)
- Flatulence/wind (production of excessive gas), bloating. Flatulence often goes away after a few days of treatment.
How long does it take for lactulose to work?
It usually takes around 2-3 days before a full laxative effect is achieved. Some patients may experience the result within 24 hours of the first use. Stool frequency with lactulose use is dose-dependent. Higher doses of lactulose increase stool frequency (Portalatin & Winstead, 2012).
Osmotic laxatives: MACROGOLS
Macrogol produces a laxative effect through osmotic effects. Macrogols containing osmotic laxatives are used to relieve constipation and additionally to help in resolving faecal impaction. Macrogol laxatives are most commonly used in the form of a powder (sachets), which patients need to mix with water. Macrogols are also available as ready-made oral solutions. Once mixed with water, the reconstituted solution should be refrigerated (2°C-8°C) and used within 6 hours.
Macrogol containing laxatives: age restrictions (adult vs. children range)
Macrogol laxatives are licensed as P medicines (available to buy from a pharmacy) to treat constipation in adults and children from 12 years of age.
Children’s range of macrogol laxatives can only be obtained on prescription with licensed use for children aged 2-11.
An adult version of macrogol laxatives usually contains 13.125g of macrogol 3350 per sachet, whereas the children’s version contains a half amount of macrogol 3350, 6.563 g per dose.
Osmotic laxatives containing macrogols:
Laxido is available as an orange powder for making an oral solution (sachets) containing Macrogol 3350 13.125g per sachet. Laxido is licensed for adults and children from 12 years of age. Laxido is a pharmacy-only medicine. Lear more about Laxido and Laxido alternative laxatives.
Can Laxido be used in pregnancy?
Laxido Orange can be used during pregnancy (eMC, 2019).
The same age restrictions apply to Movicol products as to Laxido. In addition to the management of constipation, Movicol is also licensed for helping with faecal impaction. For the management of chronic constipation, prolonged use of Movicol lasting longer than two weeks in a row is not recommended.
What is the difference between Movicol and Laxido?
Find more in a related post: Laxido vs Movicol for constipation.
Movicol contains 13.125g of macrogol 3350 per sachet.
Over the counter, Movicol is available as:
- Movicol (standard): lime and lemon flavour sachets
- Movicol Chocolate sachets
- Movicol Plain sachets
- Movicol-Half sachets
- Movicol Liquid
Can Movicol be used in pregnancy?
Movicol can be used during pregnancy (eMC, 2019).
4. CosmoCol range
CosmoCol range of macrogol-containing osmotic laxatives includes:
- CosmoCol Orange Flavour oral powder sachets
- CosmoCol Lemon and Lime Flavour oral powder sachets
- CosmoCol Orange Lemon and Lime oral powder sachets
- CosmoCol Plain oral powder sachet
- CosmoCol Half oral powder 6.9g sachets
Can CosmoCol be used during pregnancy?
CosmoCol should only be used in pregnancy if treatment is considered essential by a doctor.
Less popular Molaxole is only licensed for adults and children over 12 years of age. It contains the same amount of macrogol 3350 as Laxido and Movicol. Lemon flavour Molaxole is licensed as a pharmacy-only medication for the management of constipation and faecal impaction.
Can Molaxole be used in pregnancy?
Molaxole should only be used in pregnancy if treatment is considered essential by a doctor.
Best over the counter laxatives UK – Bulk-forming laxatives
As the name suggests, bulk-forming laxatives add ‘bulk’ and increase faecal mass. Stools become softer and easier to pass. Bulk-forming laxatives are a gentle form of laxatives. Common over the counter bulk-forming laxatives include products containing dietary fibre, such as:
- ispaghula husk,
- methylcellulose and
How long does it take for bulk-forming laxatives to work?
Bulk-forming laxatives usually take from 24 to 72 hours (full effect) to work.
Side effects associated with the use of bulk-forming laxatives
Bulk-forming laxatives are generally well tolerated. Some side effects related to their use include (frequency not known):
- Flatulence (excess of wind)
- Abdominal distention (enlargement of the abdominal).
- Bulk-forming can cause intestinal obstruction, oesophageal obstruction, faecal impaction (blockage of colon/rectum)
6. Bulk-forming laxatives: FYBOGEL (ispaghula husk)
The Fybogel range of bulk-forming laxatives contains ispaghula husk as the main ingredient. Fybogel comes in the form of granules that are mixed with water. Mixed suspension should be ingested as soon as possible after mixing.
Fybogel is licensed for adults and children over 6 years of age. Fybogel can be purchased in any retail outlet (GSL license), and most pharmacies should stock it as well. Fybogel range includes:
- Fybogel Orange Granules
- Fybogel Plain Granules
- Fybogel Hi-Fibre Lemon Granules
- Fybogel Hi-Fibre Orange Granules
- Fybrogel Fibre Chews
Important points to consider:
- Fybogel (Ispaghula husk) should not be used by patients with suspected faecal impaction unless advised by a doctor.
- Ispaghula husk should always be mixed with water.
- Patients need to ensure adequate water intake to avoid potential obstruction of the throat (risk of choking) or oesophagus (risk of intestinal obstruction).
- Bulk-forming laxatives, including Fybogel, should not be used to relieve constipation caused by drugs, which reduces the movement of the gut, such as opioids, for example, codeine or co-codamol.
- Fybogel (or any other bulk-forming laxative) should not be taken before going to bed.
Can you use Fybogel during pregnancy?
Fybogel can be used in pregnancy.
7. Bulk-forming laxatives: Methylcellulose
Methylcellulose is available in the form of tablets under the brand name Celevac. Each Celevac tablet contains 500 mg of methylcellulose. Celevac tablets have few licensed uses. Celevac tablets can be used in the management of simple constipation, and interestingly as an aid to appetite control and the treatment of obesity. Celevac tablets are now discontinued and no longer available in the UK.
Although Celevac is licensed as a general sale product, most shops and even pharmacies do not stock it. Some pharmacies may stock Celevac as part of their dispensary stock, so one would need to ask the pharmacy team about the availability of this product. Alternatively, Celevac can be purchased online.
As with bulk-forming laxatives, patients are advised to drink plenty of water to avoid the possibility of faecal impaction or oesophageal obstruction due. When in contact with water, methylcellulose tablets absorb (take in) the water swell and create bulk in the stomach helping to restore regular bowel movements.
Can Celevac be used during pregnancy?
The manufacturer of Celevac advises not to use Celevac (especially in the first trimester of the pregnancy) unless the benefit outweighs the risks to the foetus.
Stimulant laxatives: start to work fast
Stimulant laxatives increase the movement of intestines by stimulating colonic nerves, which start to contract and promote bowel movement. The most common stimulant laxatives (UK) in this category include senna tablets and bisacodyl tablets and suppositories.
How long does it take for stimulant laxatives to work?
Stimulant laxatives are usually taken at night before going to bed to produce the effect in the morning (time to effect: 6-12 hours). Stimulant suppositories can produce laxative effect just in 15minutes after the insertion.
Stimulant laxatives: side effects
Common side effects associated with stimulant laxative use include:
- Gastrointestinal discomfort including pain, cramps
Can you use stimulant laxatives during pregnancy?
The use of senna is not recommended during pregnancy. It is advised not to use bisacodyl during pregnancy, especially in the first trimester. The use of bisacodyl in pregnancy should only be considered if the benefits outweigh the risks associated with the treatment.
Who cannot use stimulant laxatives?
Patients with specific conditions such:
- ileus (obstruction),
- intestinal obstruction,
- stenosis (narrowing of a passage in the body)
- inflammatory colon diseases (Crohn’s disease, ulcerative colitis)
- severe dehydration
- electrolyte depletion
- should not use stimulant laxatives.
For more details, refer to the patient information leaflet.
8. Stimulant laxatives: SENNA over the counter
Senna can be purchased in any retail outlet, including pharmacies. Senna should only be used in the short-term to treat constipation. Long-term use of a stimulant laxative may cause dysfunction of the intestine and dependence on this laxative for normal functioning.
Senna tablets are marketed under different brands, with the cheapest options being supermarket brands of senna tablets, including:
- Tesco Senna Tablets (Senna Pods)
- Boots Natural Senna Laxative
- LloydsPharmacy Senna Tablets
- Sainsbury’s Senna Tablets
Senokot is a common brand of senna tablets stocked by most supermarkets and pharmacies. There is not much difference between each product. Each product contains the same active ingredient, which is 7.5mg of Sennoside B.
Senokot vs Senokot Max
Each Max strength senna product, for example, Senokot Max Strength, contains 15mg of Sennoside B, per tablet instead of 7.5mg *standard Senna tablets). Taking two standard Senna tablets would give the same effect as taking one Senna Max tablet.
Both Senna and Senna Max tablets are licensed for adults and children from 12 years of age.
Senna drug interactions
Senna products can interact with some drugs (mainly some ‘heart’ drugs and some types of steroids), check the product information leaflet for more details or speak to a pharmacist.
Senna age restrictions
Senna tablets are licensed for adults and children who are 6 years of age or over. Senna is available in liquid form under the brand name of Senokot 7.5 mg/5 ml Syrup.
Senokot syrup can be used in children from two years of age with recommended limited time for the use of 1-2 weeks.
The use of senna products for longer than one week requires medical supervision.
9. Stimulant laxatives: BISACODYL
Similarly to senna tablets, bisacodyl tablets can be purchased in most supermarkets and pharmacies. Bisacodyl Suppositories can only be purchased from the pharmacy.
Bisacodyl tablets are sold under many different brand names, including:
- Asda Constipation Relief Tablets
- Tesco Constipation Relief
- Morrisons Laxative Tablets
- Superdrug Constipation Relief Tablets
- Sainsbury’s Constipation Relief
- Boots Constipation Relief Tablets
Bisacodyl: age restrictions
Bisacodyl tablets are licensed for adults and children from 10 years of age. Children between 4 and 10 years of age can use bisacodyl tablets only if recommended by a doctor.
Bisacodyl 10mg suppositories can be used by adults and children over 10 years of age, whereas bisacodyl 5mg suppositories by children over 4 years of age.
How long does it take for bisacodyl laxative to work?
Bisacodyl tablets are usually taken at night before going to bed, to give relief in the morning.
Bisacodyl suppositories take around 20 minutes to work; one would expect the laxative effect from 10-30 minutes after the insertion.
10. Stimulant laxatives: SODIUM PICOSULFATE
Less commonly known sodium picosulfate is available as pharmacy medicine as a branded product called Dulcolax Pico Liquid.
Dulcolax Pico Liquid is licensed for adults and children over 10 years of age.
Children under 10 years of age, including toddlers, can use Dulcolax Pico Liquid only if recommended by a doctor.
11. Stimulant laxatives: GLYCERIN SUPPOSITORIES
Glycerin suppositories can be purchased from supermarkets or pharmacies. Pharmacies are more likely to keep all size suppositories in stock. Glycerin suppositories come in three different sizes designed for three age groups:
- Glycerin Suppositories 4g adult size
- Glycerin Suppositories 2g children’s size
- Glycerin Suppositories 1g infants’ size
How long does it take for glycerine suppositories to work?
Glycerin suppositories usually take between 15 to 60 minutes to work.
Can you use glycerine suppositories during pregnancy?
Glycerin suppositories should be avoided during pregnancy. A doctor may advise using suppositories during the pregnancy.
Glycerin suppositories – possible side effects
Glycerin suppositories are well tolerated. Possible side effects may include:
- Burning/irritation after the insertion
- Abdominal pain
12. Over the counter laxatives UK: ENEMAS
Enemas are medicines which are inserted into the rectum with content administered from a nozzle. Enemas are used in the treatment of constipation, but also n preparation for X-ray examination, proctoscopy, and sigmoidoscopy.
How long does it take for an enema to work?
Enemas are very quick in relieving the symptoms of constipation. Enemas may start to work 5 minutes after the administration. Patients are advised to use an enema close to the toilet.
Where can you buy an enema for constipation?
Enemas are usually licensed as pharmacy-only medicines. Generally one needs to as a member of a pharmacy team about the availability of enemas, since enemas are usually kept in the dispensaries, away from customer view. Micralax is available on Amazon.co.uk, however at much higher price than from high street pharmacies.
Two common brands of enemas dispensed in pharmacies are:
- Micralax Micro-enema (contains sodium citrate and sodium alkylsulfoacetate)
- Cleen Ready-to-Use Enema (contains sodium dihydrogen phosphate dihydrate and disodium phosphate dodecahydrate)
Who can use enemas?
Enemas can be used by adults and children.
Can Enemase be used during pregnancy?
Enemas are not contraindicated in pregnancy, however, speak to your GP before using enemas.
Enemas: side effects
The risk of side effects associated with the use of enemas is none to very rare. Product information for Micralax Miro-enema state no reported side effects associated with its use.
The product information leaflet for Cleen Ready-to-Use Enama lists the possibility of a few very rare side effects.
The risk of side effects usually increases when enemas are misused.
13. Over the counter laxatives: Faecal softeners
Faecal softeners increase the penetration of water and fats into the stool, making the stool softer and easier to pass. Docusate sodium is the main faecal softener available as:
- Dulcoease and Dioctyl 100mg capsules
- Docusate Sodium Paediatric 12.5mg/5ml Oral Solution
- Docusate Sodium Adult 50mg/5ml Oral Solution
Docusate Sodium: age restrictions
Docusate Sodium Paediatric is licensed for infants and children from 6 months of age up to 12 years of age. Docusate Paediatric can be mixed with fruit juice or milk.
Docusate capsules and an adult oral solution are licensed for adults and children from 12 years of age.
Docusate Sodium: side effects
Docusate Sodium is generally well tolerated. Abdominal cramps can be experienced by patients taking this medication.
Can you use docusate sodium in pregnancy?
The use of docusate sodium in pregnancy is only recommended if the benefits outweigh the potential risks of the treatment.
eMC (2019). SmPC: Laxido Orange, powder for oral solution. Available at: https://www.medicines.org.uk/emc/product/6399/smpc#PREGNANCY Accessed on 12/01/2023
eMC (2019). SmPC: Movicol 13.8g sachet, powder for oral solution. Available at: https://www.medicines.org.uk/emc/product/1025/smpc#PREGNANCY Accessed on 12/01/2023
NICE (2019). Constipation. Available at: https://cks.nice.org.uk/constipation#!scenario Accessed on 12/01/2023
Portalatin M, Winstead N. (2012). Medical management of constipation. Clin Colon Rectal Surg. 2012;25(1):12–19. doi:10.1055/s-0032-1301754 Available at: https://dx.doi.org/10.1055%2Fs-0032-1301754 Accessed on 12/01/2023