Picolax sachets contain two active ingredients, sodium picosulfate and magnesium citrate, which are both laxatives.

What is Picolax used for?

  • Picolax is used to empty and cleanse the bowel before examinations, X-rays or surgical procedures that require the colon to be clean of stools, such as a colonoscopy or barium enema. It is not used to treat constipation.

How does Picolax work?

  • The laxatives in Picolax work in two different ways.
  • Sodium picosulfate is activated by the natural bacteria that are found in the colon (large intestine), so it doesn't start working until it reaches this part of the gut. It works by stimulating the nerve endings in the walls of the colon and rectum. This increases the muscle contractions in this part of the bowel, which moves the contents through the colon to the rectum so that the bowel can be emptied.
  • Magnesium citrate acts as an 'osmotic laxative'. It works by causing water to be drawn into the lower bowel.
This increases the water content and volume of the stools, and helps to 'wash out' the bowel.

How do I take Picolax?

  • Always follow the instructions given by your doctor. The time to take Picolax depends on the time of your procedure. Two doses of Picolax will be needed; the first should be taken 10 to 18 hours before the procedure and the second 4 to 6 hours before the procedure.
  • After the first dose you should have at least five 250ml drinks of clear liquids, spread over several hours. After the second dose you should have at least three 250ml drinks of clear liquids, spread over several hours. You should also drink clear liquids as needed to satisfy your thirst up until two hours before the procedure.
  • The usual dose for adults and children aged 9 years and over is one sachet for each dose. The amount of Picolax to give younger children for each dose varies with age. It is important to follow the instructions given by your doctor or pharmacist.
  • To make up a dose using a whole sachet, the contents of the sachet should be stirred into 150ml of cold water for two to three minutes, until all the powder has dissolved. The solution in the glass may feel hot as the Picolax powder dissolves; wait until it cools before drinking it.
  • If you are using less than a whole sachet to make up a dose (eg for young children) you should use 50ml of water for each spoonful of powder needed. Stir for two to three minutes, until all the powder has dissolved. The solution in the glass may feel warm as the Picolax powder dissolves; wait until it cools before giving it to your child.

What should I know before taking Picolax?

  • It's important to drink clear liquids as described above to avoid the Picolax treatment making you dehydrated. Clear liquids should include a variety of fruit juice (without pulp), soft drinks, clear soup, tea, coffee (without milk, soy or cream) and water. Do not drink only water.
  • You should expect to start having frequent loose bowel movements from any time after you have taken the first dose of Picolax. You should make sure you have access to a toilet until the effects of the medicine have worn off.

Who should not take Picolax?

  • People who are feeling sick or vomiting.
  • People who are very dehydrated.
  • People with an ulcer in the stomach or intestines.
  • People with a known or suspected blockage or perforation in the stomach or intestines.
  • People with active inflammatory bowel disease such as ulcerative colitis or Crohn's disease.
  • People with reduced ability of the stomach to empty (gastric retention).
  • People with reduced muscle activity in the intestines (ileus).
  • People with severe inflammation of the large intestine (toxic colitis).
  • People with a sudden expansion of the large intestine seen in advanced ulcerative colitis or Crohn's disease (toxic megacolon).
  • People with abdominal conditions that need urgent surgery, such as appendicitis.
  • People with congestive heart failure.
  • People with severely decreased kidney function.
  • People who have a high level of magnesium in their blood (hypermagnesaemia).
  • People with a condition called rhabdomyolysis, where there is breakdown of muscle fibres.
  • Picolax sachets contain lactose and should not be used by people with rare hereditary problems of galactose intolerance, the Lapp-lactase deficiency or glucose-galactose malabsorption.

Who may need extra monitoring while taking Picolax?

  • Elderly people.
  • Weak or debilitated people.
  • People with heart disease.
  • People who suffer from inflammatory bowel disease such as ulcerative colitis or Crohn's disease.
  • People who have recently had surgery on the stomach or intestines.
  • People with kidney problems.
  • People taking diuretic medicines, corticosteroids or lithium.
  • People who have disturbances in the normal levels of electrolytes (such as sodium and potassium) in their blood.
  • People on a controlled potassium diet.
  • People with epilepsy.

Can I use Picolax while pregnant or breastfeeding?

  • Picolax should preferably be avoided during pregnancy. Make sure your doctor knows if you are or think you could be pregnant.
  • Picolax may be used by breastfeeding mothers. It is not expected to have any harmful effects on a nursing infant.

What are the possible side effects of Picolax?

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with Picolax. Just because a side effect is stated here, it does not mean that all people using Picolax will experience that or any side effect.


  • Headache.
  • Feeling sick.
  • Pain around the anus (proctalgia).


  • Decrease in the level of potassium or sodium in the blood.
  • Vomiting.
  • Abdominal pain.
  • Confusion.
  • Seizures (convulsions).
  • Allergic reactions.
  • Rash.

Frequency unknown

  • Diarrhoea.
  • Faecal incontinence.

For more information about any other possible risks associated with Picolax, please read the information provided with the medicine or consult your doctor or pharmacist.

Can I take Picolax with other medicines?

Make sure your doctor or pharmacist what medicines you are taking, including those bought without a prescription and herbal medicines, before you start treatment with Picolax.

If you are taking any other medicines by mouth they should be taken at least two hours before and not less than six hours after taking a dose of Picolax. This is to prevent the other medicine from binding to the magnesium in Picolax, and to prevent it being flushed through the gut without it having time to be absorbed. This is particularly important for the following medicines:

  • antibiotics
  • antidiabetics
  • antiepileptics
  • chlorpromazine
  • digoxin
  • iron
  • oral contraceptives
  • penicillamine.

Picolax can sometimes cause an imbalance in the amount of fluid and salts (electrolytes) in your body. This may be more likely if you are also taking one of the medicines listed below. Ask your doctor or pharmacist for further information and advice if you are taking one of these.

  • ACE inhibitors, eg captopril, enalapril
  • antidepressants, eg amitriptyline, citalopram
  • angiotensin-II receptor antagonists, eg losartan, valsartan
  • diuretic medicines, eg furosemide or bendroflumethiazide
  • non-steroidal anti-inflammatory painkillers (NSAIDs) , eg diclofenac, indometacin
  • steroid medicines, eg prednisolone, dexamethasone.