Dyspamet Chewtab Tablets 200mg

1. Name Of The Medicinal Product

DYSPAMET* CHEWTAB* TABLETS 200 mg.

2. Qualitative And Quantitative Composition

'Dyspamet' 'Chewtab' Tablets contain 200 mg cimetidine per tablet.

3. Pharmaceutical Form

White, square, chewable tablets with a surface design consisting of a raised portion towards one side of the tablet and a curved depression over the rest of the surface.

4. Clinical Particulars

4.1 Therapeutic Indications

Cimetidine is a histamine H₂-receptor antagonist which rapidly inhibits both basal and stimulated gastric secretion of acid and reduces pepsin output.

'Dyspamet' is indicated in the treatment of duodenal and benign gastric ulceration, recurrent and stomal ulceration, oesophageal reflux disease and other conditions where reduction of gastric acid by cimetidine has been shown to be beneficial: persistent dyspeptic symptoms with or without ulceration, particularly meal-related upper abdominal pain; the prophylaxis of gastrointestinal haemorrhage from stress ulceration in seriously ill patients; before general anaesthesia in patients thought to be at risk of acid aspiration (Mendelson's) syndrome, particularly obstetric patients during labour; to reduce malabsorption and fluid loss in the short bowel syndrome; and in pancreatic insufficiency to reduce degradation of enzyme supplements. 'Dyspamet' is also recommended in the management of the Zollinger-Ellison syndrome.

4.2 Posology And Method Of Administration

Oral: 'Dyspamet' tablets should be chewed thoroughly before swallowing. The total daily dose should not normally exceed 2.4 g. Dosage should be reduced in patients with impaired renal function (see Section 4.4).

Adults: The usual dosage is 400 mg twice a day with breakfast and at bedtime. For patients with duodenal or benign gastric ulceration, a single daily dose of 800 mg at bedtime is recommended. Other effective regimens are 200 mg three times a day with meals and 400 mg at bedtime (1.0 g/day) and, if inadequate, 400 mg four times a day (1.6 g/day) also with meals and at bedtime.

Symptomatic relief is usually rapid. Treatment should be given initially for at least four weeks (six weeks in benign gastric ulcer). Most ulcers will have healed by that stage, but those which have not will usually do so after a further course of treatment.

Treatment may be continued for longer periods in those patients who may benefit from reduction of gastric secretion and the dosage may be reduced as appropriate to 400 mg at bedtime or 400 mg in the morning and at bedtime

In patients with benign peptic ulcer disease, relapse may be prevented by continued treatment, usually with 400 mg at bedtime; 400 mg in the morning and at bedtime has also been used.

In oesophageal reflux disease, 400 mg four times a day, with meals and at bedtime, for four to eight weeks is recommended to heal oesophagitis and relieve associated symptoms.

In patients with very high gastric acid secretion (e.g. Zollinger-Ellison syndrome) it may be necessary to increase the dose to 400 mg four times a day, or in occasional cases further.

Antacids can be made available to all patients until symptoms disappear.

In the prophylaxis of haemorrhage from stress ulceration in seriously ill patients, doses of 200-400 mg can be given every four to six hours.

In patients thought to be at risk of acid aspiration syndrome a dose of 400 mg can be given 90-120 minutes before induction of general anaesthesia or, in obstetric practice, at the start of labour. While such a risk persists, a dose of up to 400 mg may be repeated at four-hourly intervals as required up to the usual daily maximum of 2.4 g. The usual precautions to avoid acid aspiration should be taken.

In the short bowel syndrome, e.g. following substantial resection for Crohn's disease, the usual dosage range (see above) can be used according to individual response.

To reduce degradation of pancreatic enzyme supplements, 800-1600 mg a day may be given according to response in four divided doses, one to one and a half hours before meals.

Elderly: The normal adult dosage may be used unless renal function is markedly impaired (see Sections 4.4 and 4.8).

Children: Experience in children is less than that in adults. In children more than two years old, cimetidine 25-30 mg/kg body weight per day in divided doses may be administered.

The use of cimetidine in children less than two years old is not fully evaluated; 20 mg/kg body weight per day in divided doses has been used.

4.3 Contraindications

Hypersensitivity to cimetidine

4.4 Special Warnings And Precautions For Use

Dosage should be reduced in patients with impaired renal function according to creatinine clearance. The following dosages are suggested: creatinine clearance of 0 to 15 ml per minute, 200 mg twice a day; 15 to 30 ml per minute, 200 mg three times a day; 30 to 50 ml per minute, 200 mg four times a day; over 50 ml per minute, normal dosage. Cimetidine is removed by haemodialysis, but not to any significant extent by peritoneal dialysis.

Clinical trials with cimetidine of over six years continuous treatment and more than 15 years' widespread use have not revealed unexpected adverse reactions related to long

Cimetidine treatment can mask the symptoms and allow transient healing of gastric cancer. This potential delay in diagnosis should particularly be borne in mind in patients of middle age and over with new or recently changed dyspeptic symptoms.

4.5 Interaction With Other Medicinal Products And Other Forms Of Interaction

Cimetidine can prolong the elimination of drugs metabolised by oxidation in the liver. Although pharmacological interactions with a number of drugs, e.g. diazepam, propranolol, have been demonstrated, only those with oral anticoagulants, phenytoin, theophylline and intravenous lignocaine appear, to date, to be of clinical significance. Close monitoring of patients on 'Dyspamet' receiving oral anticoagulants or phenytoin is recommended and a reduction in the dosage of these drugs may be necessary.

In patients on drug treatment or with illnesses that could cause falls in blood cell count, the possibility that H₂-receptor antagonism could potentiate this effect should be borne in mind.

4.6 Pregnancy And Lactation

Although tests in animals and clinical evidence have not revealed any hazards from the administration of cimetidine during pregnancy or lactation, both animal and human studies have shown that it does cross the placental barrier and is excreted in milk. As with most drugs, the use of 'Dyspamet' should be avoided during pregnancy and lactation unless essential.

4.7 Effects On Ability To Drive And Use Machines

Not applicable.

4.8 Undesirable Effects

Over 56 million patients have been treated with cimetidine worldwide and adverse reactions have been infrequent. Diarrhoea, dizziness or rash, usually mild and transient, and tiredness have been reported. Gynaecomastia has been reported and is almost always reversible on discontinuing treatment.

Biochemical or biopsy evidence of reversible liver damage has been reported occasionally. Reversible confusional states have occurred, usually in the elderly or already very ill patients, e.g. those with renal failure. Thrombocytopenia and leucopenia, including agranulocytosis (see Section 4.4), reversible on withdrawal of treatment, have been reported rarely; pancytopenia and aplastic anaemia have been reported very rarely. There have been very rare reports of interstitial nephritis, acute pancreatitis, fever, headache, myalgia, arthralgia, sinus bradycardia, tachycardia and heart block, all reversible on withdrawal of treatment. In common with other H₂-receptor antagonists, there have been very rare reports of anaphylaxis. Alopecia has been reported but no causal relationship has been established. Reversible impotence has also been very rarely reported but no causal relationship has been established at usual therapeutic doses. Isolated increases of plasma creatinine have been of no clinical significance.

4.9 Overdose

Acute overdosage of up to 20 grams cimetidine has been reported several times with no significant ill effects. Induction of vomiting and/or gastric lavage may be employed together with symptomatic and supportive therapy.

5. Pharmacological Properties

5.1 Pharmacodynamic Properties

Cimetidine is a histamine H₂-receptor antagonist which rapidly inhibits both basal and stimulated gastric secretion of acid and reduces pepsin output.

5.2 Pharmacokinetic Properties

Cimetidine is well absorbed after oral-administration, metabolised in the liver and excreted mainly through the kidney with a half-life of about two hours. The effects on acid secretion are of longer duration.

5.3 Preclinical Safety Data

Not applicable.

6. Pharmaceutical Particulars

6.1 List Of Excipients

Eudragit (E100), sorbitol(E420), lactose, croscarmellose sodium (type A), sodium saccharin, aspartame, magnesium stearate (E572), aniseed and butterscotch flavourings.

6.2 Incompatibilities

Not applicable.

6.3 Shelf Life

3 years

6.4 Special Precautions For Storage

Store the tablets in a dry place.

6.5 Nature And Contents Of Container

'Chewtab' Tablets, in opaque blister packs of 120 (20 x 6).

6.6 Special Precautions For Disposal And Other Handling

None stated.

7. Marketing Authorisation Holder

Smith Kline and French Laboratories Ltd

Mundells

Welwyn Garden City

Herts AL7 1EY

Trading as:

SmithKline Beecham Pharmaceuticals

Mundells

Welwyn Garden City

Herts AL7 1EY

8. Marketing Authorisation Number(S)

PL 0002/0148

9. Date Of First Authorisation/Renewal Of The Authorisation

13.7.87/25.7.97.

10. Date Of Revision Of The Text

4.2.00

* Trade mark