LENAMET INJECTION 200 mg/2 mL
SCHEDULING STATUS: S3
PROPRIETARY NAME (and dosage form):
LENAMET INJECTION 200 mg/2 mL
COMPOSITION: Each tablet contains 200 mg or 400 mg Cimetidine respectively.
Each ampoule contains 200 mg Cimetidine per 2 mL.
PHARMACOLOGICAL CLASSIFICATION: A 11.4.3 Medicines acting on gastro-intestinal tract: Other.
PHARMACOLOGICAL ACTION: Cimetidine is a histamine H2-receptor antagonist. Its main action is to inhibit gastric acid secretion. It also inhibits competitively the other actions of histamine mediated by H2-receptors. The decrease in gastric acid secretion occurs regardless of the nature of the physiological stimulus to secretion, i.e. basal or unstimulated secretion, is reduced. Both the volume of secretion and the concentration of acid in the secretion are reduced.
INDICATIONS: The treatment of benign gastric and duodenal ulcers, reflux oesophagitis, Zollinger-Ellison syndrome and in other conditions associated with gastric hypersecretory states, such as systemic mastocytosis and multiple endocrine adenomas. It is also indicated at reduced dosage for duodenal ulcer recurrence in selected patients.
CONTRA-INDICATIONS: Lenamet is not recommended for minor digestive complaints. It is also not recommended for patients with impaired renal function.
DOSAGE AND DIRECTIONS FOR USE: Clinical experience with Lenamet in children is limited. Therefore Lenamet therapy cannot be recommended for children.
The total daily use by any route should not exceed 2,4 g.
Oral: Treatment should be continued for at least 4 weeks.
Duodenal ulcer: 400 mg twice daily and at bedtime, or 800 mg at bedtime.
Maintenance dose for recurrent duodenal ulcer: One 400 mg tablet at bedtime.
Benign active gastric ulceration: The usual preferred dose is 200 mg three times a day with meals and 400 mg at bedtime.
Alternatively, 400 mg at breakfast with 400 mg at bedtime or a single dose of 800 mg at bedtime can be given.
Gastric hypersecretory conditions (eg. Zollinger-Ellison syndrome, systemic mastocytosis multiple endocrine adenomas): The usual dose is 200 mg three times a day with meals and 400 mg at bedtime, but the dosage may need to be increased to 400 mg four times daily, with meals and at night, for patients at risk from stress-related ulceration of the upper gastro-intestinal tract, such as those with fulminant hepatic failure. The dosage should be adjusted as needed, and therapy continued for as long as clinically indicated.
Reflux oesophagitis: 400 mg four times a day with meals and at bedtime for 4 to 8 weeks.
Parenteral: Where required parenteral administration may be used.
The dose with intravenous or intramuscular injections, is normally 200 mg. Injections may be repeated at 4 or 6 hourly intervals.
The 200 mg injection for intravenous use should be diluted in 0,9% Normal Saline (or other compatible solution) to a total volume of 20 mL and given very slowly, at least over 2 minutes.
The dose by intravenous infusion is usually 50 to 100 mg/hour for 2 hours and repeated at 4 to 6 hourly intervals. The maximum infusion rate should not usually exceed 150 mg/hour or 2 mg/kg body mass/hour. Intravenous infusion is preferred in patients where cardiovascular impairment is present.
Lenamet injection has been shown to be compatible with Dextrose (5 and 10 %), and Normal Saline (0,9 %) solutions for intravenous infusion and the resultant solution is stable for 1 week at normal room temperature.
SIDE-EFFECTS AND SPECIAL PRECAUTIONS: Constipation or diarrhoea, muscle pain, dizziness, tiredness and skin rash may occur. Gynaecomastia or galactorrhoea, increases in serum-transaminase values, increases in plasma-creatinine values and interstitial nephritis have been reported. Blood disorders such as thrombocytopenia, granulocytopenia, agranulocytosis and pancytopenia have been reported.
Neural dysfunction has been encountered, particularly with high doses in elderly patients, patients with organic brain syndrome and in association with impaired renal excretion. The effects include confusion, slurred speech, delirium, hallucinations, and coma. Cases of fever, which cleared on withdrawal of Lenamet have been reported. Acute pancreatitis, cardiac arrhythmias, allergic reactions, arthralgia, myalgia, hypotension and loss of libido may occur.
Caution is necessary when cimetidine is given at a dose of more than 1 g daily for prolonged periods to patients with impaired spermatogenesis. Impotence may occur in men receiving relatively high doses.
Withdrawal of cimetidine after a period of treatment has been followed by relapses in the symptoms of ulcer and even by perforation of duodenal, oesophageal or gastric ulcers.
Raised serum creatinine concentration may occur during therapy but clinical significance of this has not yet been established.
The possibility of malignancy in gastric ulcer should be excluded since the symptoms may respond to Lenamet treatment. On current evidence it is recommended that no anticholinergic agents would be administered concurrently with Lenamet for maintenance treatment because of the possibility of interaction.
It is advisable to avoid administration of cimetidine during pregnancy and lactation.
In view of a report that glucose handling was impaired after long-term Lenamet administration, caution should be observed in the treatment of diabetics or elderly patients.
Intravenous injection of Lenamet Injection 200 mg/2 mL (cimetidine) should be given slowly and intravenous infusion is recommended in patients with cardiovascular impairment.
The use of Lenamet in patients suffering from acute forms of porphyria, especially variegate porphyria and to a lesser extent acute intermittent porphyria and hereditary coproporphyria, is contentious, and Lenamet should thus be used with caution in these patients.
Interactions: Lenamet has been reported to reduce the hepatic metabolism of warfarin-type anticoagulants, phenytoin, propranolol, chlordiazepoxide, diazepam and theophyllin, thereby delaying elimination and increasing blood levels of these medicines.
Since clinically significant effects have been reported with warfarin anticoagulants, close monitoring of prothrombin time is recommended, and adjustment of the anticoagulant dose may be necessary when Lenamet is administered concomitantly.
Interaction with phenytoin and theophylline has also been reported to increase the adverse clinical effects of these medicines.
Dosages of the medicines mentioned above and other similarly metabolized medicines may require adjustment when starting or stopping concomitantly administered Lenamet to maintain safe, optimum therapeutic blood levels.
KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT: See Side-effects and special precautionsabove. Treatment is supportive and symptomatic.
Lenamet-200: A pale green film-coated biconvex tablet with a diameter of 9,5 mm, engraved with a mortar and pestle on one side and LENAMET 200on the reverse.
Lenamet-400: A pale green film-coated biconvex tablet with a diameter of 11,2 mm, engraved with a mortar and pestle on one side and LENAMET 400on the reverse.
Lenamet Injection 200 mg/2 mL: A 2 mL clear ampoule containing a clear, pale straw coloured solution.
Packs of 60 and 150 tablets.
Blister packs of 56 tablets.
200 mg/2 mL injection
2 mL clear ampoules in packs of 10.
STORAGE INSTRUCTIONS: Store in a cool place below 25°C. Protect from light.
KEEP OUT OF REACH OF CHILDREN.