BMA Concise Guide to Medicine & Drugs


Brand name Celevac

Used in the following combined preparations None


Drug group Laxative and antidiarrhoeal drug

Overdose danger rating Low

Dependence rating Low

Prescription needed No

Available as generic No


Methylcellulose is a laxative used for the treatment of constipation, diverticular disease, and irritable bowel syndrome. Taken by mouth, methylcellulose is not absorbed into the bloodstream but remains in the intestine. It absorbs up to 25 times its volume of water, thereby softening faeces and increasing their volume. It is also used to reduce the frequency and increase the firmness of faeces in chronic watery diarrhoea, and to control the consistency of faeces after colostomies and ileostomies.

Methylcellulose preparations are also used with appropriate dieting in some cases of obesity. The bulking agent swells to give a feeling of fullness, thereby encouraging adherence to a reducing diet.


Follow instructions on the label. Call your doctor if symptoms worsen.

How taken/used Tablets.

Frequency and timing of doses 1–2 x daily. If used as laxative, unless otherwise instructed, break in mouth and swallow with full glass of water; do not take at bedtime.

Adult dosage range 1.5–6g daily.

Onset of effect Within 24 hours.

Duration of action Up to 3 days.

Diet advice If taken as a laxative, drink plenty of fluids, and drink at least 300ml with each dose. If taken for diarrhoea, avoid liquids for 30 minutes before and after each dose.

Storage Keep in original container at room temperature out of the reach of children.

Missed dose Take as soon as you remember. Take the next dose as scheduled.

Stopping the drug Can be safely stopped as soon as you no longer need it.

Exceeding the dose An occasional unintentional extra dose is unlikely to be a cause for concern. But if you notice any unusual symptoms, or if a large overdose has been taken, notify your doctor.


Adverse effects are rare, but when taken by mouth methylcellulose may cause abdominal distension and flatulence. Insufficient fluid intake may cause blockage of the oesophagus (gullet) or intestine. Consult your doctor if you experience severe abdominal pain or if you have had no bowel movement for 2 days after taking the drug.




Be sure to consult your doctor or pharmacist before taking this drug if:

· You have severe constipation and/or abdominal pain.

· You have unexplained rectal bleeding.

· You have difficulty in swallowing.

· You vomit readily.

· You are taking other medicines.

Pregnancy No evidence of risk to developing baby, but discuss with your doctor.

Breast-feeding No evidence of risk.

Infants and children Reduced dose necessary, but discuss with your doctor.

Over 60 No special problems.

Driving and hazardous work No known problems.

Alcohol No known problems.


No problems expected.