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Pentasa Enema (Mesalazine)

Active Ingredient:
Ferring Pharmaceuticals Ltd See contact details
About Medicine
{healthcare_pro_orange} This information is for use by healthcare professionals
Last updated on emc: 21 Jul 2023
1. Name of the medicinal product

PENTASA® Mesalazine Enema, 1g

2. Qualitative and quantitative composition

Each enema bottle contains mesalazine 1g in 100ml.

For a full list of excipients, see section 6.1.

3. Pharmaceutical form

Rectal suspension.

Each bottle contains 100ml of a white to slightly yellow suspension with a pH value between 4.4 and 5.0.

4. Clinical particulars
4.1 Therapeutic indications

PENTASA Mesalazine Enema is indicated for the treatment of ulcerative colitis affecting the distal colon and rectum.

4.2 Posology and method of administration


Ulcerative Colitis

Adult dose:

The recommended dosage is one enema at bedtime.

Paediatric population:

There is little experience and only limited documentation for an effect in children

Method of administration:

For rectal use.

A visit to the toilet is recommended before administration, see separate instructions for use.

Shake the enema container well before use. The enema is protected by an aluminium foil bag and should be used immediately after opening of the bag

4.3 Contraindications

PENTASA is contraindicated in:

- patients with known hypersensitivity to mesalazine, salicylates or any of the excipients, listed in section 6.1

- patients with severe liver and/or renal impairment

4.4 Special warnings and precautions for use

Caution is recommended when treating patients allergic to sulphasalazine (risk of allergy to salicylates). Severe cutaneous adverse reactions (SCARs), including Drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), have been reported in association with mesalazine treatment. In case of acute symptoms of intolerance, i.e. abdominal cramps, abdominal pain, fever and severe headache, and/or the first appearance of signs and symptoms of severe skin reactions, such as skin rash, mucosal lesions, or any other signs of hypersensitivity, the treatment should be discontinued immediately.

Caution is recommended in patients with impaired liver function. Liver function parameters like ALT or AST should be assessed prior to and during treatment, at the discretion of the treating physician.

The drug is not recommended for use in patients with impaired renal function and in patients with haemorrhagic diathesis. Baseline renal function measurement is required in all patients initiating treatment with mesalazine. Urinary status (dip sticks) should be determined prior to and during treatment at the discretion of the treating physician. The renal function should be regularly monitored (e.g. serum creatinine), especially during the initial phase of treatment based on clinical judgment taking baseline renal function into account. Mesalazine induced nephrotoxicity should be suspected in patients developing renal dysfunction during treatment. The concurrent use of other known nephrotoxic agents, such as NSAIDs and azathioprine, may increase the risk of renal reactions. Treatment should be discontinued if renal function deteriorates.

Patients with pulmonary disease, in particular asthma, should be very carefully monitored during a course of treatment, please refer to section 4.8.

Mesalazine-induced cardiac hypersensitivity reactions (myo- and pericarditis) have been reported rarely. Serious blood dyscrasias have been reported very rarely with mesalazine (see section 4.5). Blood tests for differential blood counts is recommended prior to and during treatment, at the discretion of the treating physician. Treatment should be discontinued on suspicion or evidence of these adverse reactions.

Cases of nephrolithiasis have been reported with the use of mesalazine including stones with a 100% mesalazine content. It is recommended to ensure adequate fluid intake during treatment.

As a guideline, follow-up tests are recommended 14 days after commencement of treatment, then a further two to three tests at intervals of 4 weeks. If the findings are normal, follow-up tests should be carried out every three months. If additional symptoms occur, these tests should be performed immediately.

If a patient develops dehydration while on treatment with mesalazine, normal electrolyte levels and fluid balance should be restored as soon as possible.

Mesalazine may produce red-brown urine discoloration after contact with sodium hypochlorite bleach (e.g. in toilets cleaned with sodium hypochlorite contained in certain bleaches).

4.5 Interaction with other medicinal products and other forms of interaction

No interaction studies have been performed. Combination therapy with PENTASA and azathioprine, or 6-mercaptopurine, or thioguanine, have shown a higher frequency of myelosuppressive effects, and an interaction cannot be ruled out, however, the mechanism behind the interaction is not established. Regular monitoring of white blood cells is recommended and the dosage regimen of thiopurine should be adjusted accordingly.

There is weak evidence that mesalazine might decrease the anticoagulant effect of warfarin.

4.6 Fertility, pregnancy and lactation

PENTASA should not be used during pregnancy and lactation except when the potential benefit of the treatment outweighs the possible hazards in the opinion of the physician. The underlying condition itself (Inflammatory bowel disease (IBD)) may increase risks for adverse pregnancy outcome.


Mesalazine is known to cross the placental barrier. and its concentration in umbilical cord plasma is lower than the concentration in maternal plasma. The metabolite acetyl-mesalazine is found at similar concentrations in umbilical cord and maternal plasma. Animal studies on oral mesalazine do not indicate direct or indirect harmful effects with respect to pregnancy, embryo-foetal development, parturition or postnatal development. There are no adequate and well-controlled studies of PENTASA use in pregnant women. Limited published human data on mesalazine show no increase in the overall rate of congenital malformations. Some data show an increased rate of preterm birth, stillbirth, and low birth weight; however, these adverse pregnancy outcomes are also associated with active inflammatory bowel disease.

Blood disorders (leucopenia, thrombocytopenia, anaemia) have been reported in new-borns of mothers being treated with PENTASA.

In one single case after long-term use of a high dose of mesalazine (2-4 g, orally) during pregnancy, renal failure in a neonate was reported.


Mesalazine is excreted in breast milk. The mesalazine concentration in breast milk is lower than in maternal blood, whereas the metabolite, acetyl mesalazine appears in similar or increased concentrations. No controlled studies with PENTASA during breast-feeding have been carried out. Only limited experience during lactation in women after oral application is available to date. Hypersensitivity reactions like diarrhoea cannot be excluded. If the infant develops diarrhoea, breast-feeding should be discontinued.


Animal data on mesalazine show no effect on male and female fertility

4.7 Effects on ability to drive and use machines

PENTASA has no or negligible influence on the ability to drive and/or use machines .

4.8 Undesirable effects

Summary of the safety profile

The most frequent adverse reactions seen in clinical trials are diarrhoea, nausea, abdominal pain, headache, vomiting, and rash. Hypersensitivity reactions and drug fever may occasionally occur, and severe cutaneous adverse reactions (SCARs), including Drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens- Johnson syndrome (SJS) and Toxic epidermal necrolysis (TEN), have been reported in association with mesalazine treatment (see section 4.4).

Following rectal administration local reactions such as pruritus, rectal discomfort and urge may occur.

Frequency of adverse effects, based on clinical trials and reports from post-marketing surveillance



≥ 1/100 to <1/10


≥ 1/10,000 to ≤ 1/1,000

Very rare

≤ 1/10,000

Not known (cannot be estimated from the available data).

Blood and the lymphatic system disorders

Altered blood counts (anaemia, aplastic anaemia, agranulocytosis, neutropenia, leukopenia (incl. granulocytopenia), pancytopenia, thrombocytopenia, and eosinophilia (as part of an allergic reaction)).

Immune system disorders

Hypersensitivity reaction including anaphylactic reaction,

Nervous system disorders



Peripheral neuropathy

Cardiac disorders



Respiratory, thoracic and mediastinal disorders

Allergic alveolitis, allergic and fibrotic lung reactions (incl. dyspnoea, coughing, bronchospasm, pulmonary eosinophilia, interstitial lung disease, pulmonary infiltration, pneumonitis)

Gastrointestinal disorders


Abdominal pain




Acute pancreatitis*

Increased amylase (blood and/or urine)


Hepato-biliary disorders

Increased liver enzymes, cholestasis parameters and bilirubin, hepatotoxicity (incl. hepatitis*, cholestatic hepatitis, cirrhosis, hepatic failure)

Skin and subcutaneous tissue disorders

Rash (incl. urticaria, erythematous rash)


Alopecia (reversible), dermatitis allergic, erythema multiforme

Stevens-Johnson Syndrome (SJS)/Toxic epidermal necrolysis (TEN), Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)

Musculoskeletal and connective tissue disorders



Lupus erythematosus-like syndrome

Renal and urinary disorders

Renal function impairment**** (incl. interstitial nephritis* (acute and chronic), nephrotic syndrome, renal insufficiency acute/chronic)


Nephrolithiasis ***

Urine discolouration***

Reproductive system and breast disorders

Oligospermia (reversible)

General disorders and administration site conditions

Anal discomfort and irritation at the application site, pruritus (anal), rectal tenesmus

Drug Fever

(*) The mechanism of mesalazine-induced myo- and pericarditis, pancreatitis, nephritis and hepatitis is unknown, but it might be of allergic origin.

(**) Photosensitivity: More severe reactions are reported in patients with pre-existing skin conditions such as atopic dermatitis and atopic eczema.

(***) See section 4.4 for further information.

(****) Renal failure has been reported. Mesalazine-induced nephrotoxicity should be suspected in patients developing renal dysfunction during treatment.

It is important to note that several of these disorders can also be attributed to the inflammatory bowel disease itself.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme, website:, or search for MHRA Yellow Card in the Google Play or Apple App Store.

4.9 Overdose

Acute experience in animals:

A single intravenous dose of mesalazine in rats of 920 mg/kg and single oral doses of mesalazine in pigs up to 5g/kg were not lethal.

Human experience:

There is limited clinical experience with overdose of PENTASA which does not indicate renal or hepatic toxicity. Since PENTASA is an amino salicylate, symptoms of salicylate toxicity may occur. Symptoms of salicylate over dosage are well described in the literature.

There have been reports of patients taking oral daily doses of 8 grams for a month without any adverse events

There is no specific antidote and the treatment is symptomatic and supportive.

The treatment at hospital includes close monitoring of renal function.

5. Pharmacological properties
5.1 Pharmacodynamic properties

Pharmacotherapeutic group: Intestinal anti-inflammatory agents, aminosalicylic acid and similar agents ATC code: A07 EC02

Mesalazine is the active component of sulphasalazine, which has been used for a long time in the treatment of ulcerative colitis and Crohn's disease. The therapeutic value of mesalazine appears to be due to local effect on the inflamed intestinal tissue, rather than to systemic effect. There is information suggesting that severity of colonic inflammation in ulcerative colitis patients treated with mesalazine is inversely correlated with mucosal concentrations of mesalazine.

Increased leucocyte migration, abnormal cytokine production, increased production of arachidonic acid metabolites, particularly leukotriene B4 and increased free radical formation in the inflamed intestinal tissue are all present in patients with inflammatory bowel disease. The mechanism of action of mesalazine is not fully understood although mechanisms such as activation of the γ -form of peroxisome proliferator-activated receptors (PPAR-γ ) and inhibition of nuclear factor-kappa B (NF-κ B) in the intestinal mucosa have been implicated. Mesalazine has in-vitro and in-vivo pharmacological effects that inhibit leucocyte chemotaxis, decrease cytokine and leukotriene production and scavenge for free radicals. It is currently unknown which, if any of these mechanisms play a predominant role in the clinical efficacy of mesalazine.

5.2 Pharmacokinetic properties

General Characteristics of the Active Substance

Disposition and local availability:

The therapeutic activity of mesalazine most likely depends on a local contact of the drug with the diseased area of the intestinal mucosa. PENTASA enemas are designed to provide the distal part of the intestinal tract with high concentrations of mesalazine and a low systemic absorption. The enemas have been shown to reach and cover the descending colon.


The absorption following rectal administration is low, but depends on the dose, the formulation and the extent of spread. Based on urine recoveries in healthy volunteers under steady-state conditions given a daily dose of 2g (1g x 2), about 15-20% of the dose is absorbed after administration of enemas.


Mesalazine and acetyl mesalazine do not cross the blood brain barrier. Protein binding of mesalazine is approximately 50% and of acetyl mesalazine about 80%.


Mesalazine is metabolised both pre-systemically by the intestinal mucosa and systemically in the liver to N-acetyl mesalazine (acetyl mesalazine) principally by NAT-1. Some acetylation also occurs through the action of colonic bacteria. The acetylation seems to be independent of the acetylator phenotype of the patient.


The plasma half-life of pure mesalazine is approximately 40 minutes and for acetyl mesalazine approximately 70 minutes. Both substances are excreted in urine and faeces. The urinary excretion consists mainly of acetyl mesalazine.

Characteristics in patients:

The systematic absorption following administration of PENTASA enemas has been shown to be significantly decreased in patients with active ulcerative colitis compared to those in remission.

5.3 Preclinical safety data

Toxic renal effects have been demonstrated in all species tested. Rat and monkey dosages and plasma concentrations at the No Observed Adverse Effect Levels (NOAELs) exceed those used in humans by a factor of 2-7.2.

In vitro test systems and in-vivo studies showed no evidence of mutagenic effects. Studies on the tumourigenic potential carried out in rats showed no evidence of any substance-related increase in the incidence of tumours.

Animal studies on oral mesalazine do not indicate direct or indirect harmful effects with respect to fertility, pregnancy, embryo-foetal development, parturition or postnatal development.

Mesalazine is deemed not to pose a risk to the environment at the doses prescribed for use in patients

6. Pharmaceutical particulars
6.1 List of excipients

Disodium edetate

Sodium metabisulphite

Sodium acetate

Hydrochloric acid

Purified water

6.2 Incompatibilities

None known.

6.3 Shelf life

36 months.

6.4 Special precautions for storage

Do not store above 25° C. Do not refrigerate or freeze.

Keep bottle in the outer carton to protect from light.

6.5 Nature and contents of container

Polyethylene enema bottles fitted with a tip and valve for rectal application.

The bottles are supplied in nitrogen-filled aluminium-foil bags.

Pack size: Carton containing 7 x 100ml bottles, all individually foil-wrapped.

6.6 Special precautions for disposal and other handling

The enema may colour the linen and toilet.

Any unused product or waste should be disposed of in accordance with local requirements.

7. Marketing authorisation holder

Ferring Pharmaceuticals Ltd.

Drayton Hall

Church Road

West Drayton


United Kingdom

8. Marketing authorisation number(s)

PL 03194/0027

9. Date of first authorisation/renewal of the authorisation

4th February 2004

10. Date of revision of the text

16th May 2023

Ferring Pharmaceuticals Ltd
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Drayton Hall, Church Road, West Drayton, UB7 7PS, UK
+44 (0)844 931 0050
+44 (0)844 931 0051
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[email protected]
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0800 111 4125