LOSEC

What it is

LOSEC is omeprazole magnesium, a substituted benzimidazole. LOSEC is available in 10 mg and 20 mg tablets containing omeprazole magnesium 10.3 mg and 20.6 mg, respectively. LOSEC is a proton pump inhibitor that reversibly reduces gastric acid secretion by specifically inhibiting the gastric enzyme H+, K+-ATPase, the proton pump, in the acid environment of the intracellular canaliculi within the parietal cell.

Approved indications —

Relief of heartburn and other symptoms associated with gastro-oesophageal reflux disease (GORD) — Treatment and prevention of relapse of erosive oesophagitis — Treatment of duodenal and gastric ulcer — Combination therapy for the treatment of peptic ulcer disease associated with Helicobacter pylori infection — Treatment of gastric and duodenal ulcers and erosions associated with non-steroidal anti-inflammatory drugs — Prevention of gastric and duodenal ulcers and erosions associated with non-steroidal anti-inflammatory drugs in patients assessed as being at high risk of gastroduodenal ulcer or complications of gastroduodenal ulcer — Long-term prevention of relapse in gastric and duodenal ulceration, in patients proven to be Helicobacter pylori negative, or in whom eradication is inappropriate, e.g. the elderly, or ineffective — Treatment of Zollinger-Ellison Syndrome

Dosing overview

For symptomatic GORD, the recommended dose for symptom relief is LOSEC 10 mg to 20 mg once daily for a maximum of 4 weeks. For erosive oesophagitis, the recommended healing dosage is LOSEC 20 mg once daily for 4 to 8 weeks. After healing, maintenance therapy is LOSEC 10 mg once daily, or if needed, increased to LOSEC 20 mg once daily.

Key safety warnings

Malignancy should be excluded in patients with alarm symptoms such as significant unintentional weight loss, recurrent vomiting, dysphagia, haematemesis or melaena, and when gastric ulcer is suspected or present, as treatment with omeprazole may alleviate symptoms and delay diagnosis. Concomitant use of omeprazole and clopidogrel should be avoided. Acute interstitial nephritis has been observed in patients taking proton pump inhibitors including omeprazole and may occur at any point during PPI therapy, generally attributed to idiopathic hypersensitivity reaction. Omeprazole should be discontinued if acute interstitial nephritis develops. Daily treatment with acid-suppressing medicines over a long period of time such as longer than 3 years may lead to malabsorption of cyanocobalamin (vitamin B-12) caused by hypo- or achlorhydria. Some published studies suggest that proton pump inhibitor therapy may be associated with an increased risk for osteoporosis-related fractures, particularly in patients who received high-dose and long-term PPI therapy (a year or longer). Patients should use the lowest dose and shortest duration of PPI therapy appropriate to the condition being treated. Hypomagnesaemia, both symptomatic and asymptomatic, has been reported rarely in patients treated with PPIs, with serious adverse events including tetany, arrhythmias and seizures. In most patients, treatment required magnesium replacement and discontinuation of the PPI. Severe cutaneous adverse reactions such as erythema multiforme, Stevens Johnson syndrome, toxic epidermal necrolysis and drug reaction with eosinophilia and systemic symptoms have been reported very rarely with omeprazole treatment. Omeprazole should be discontinued immediately upon signs and symptoms of severe skin reactions.

Contraindications

LOSEC is contraindicated in patients with hypersensitivity to omeprazole magnesium, substituted benzimidazoles or any other ingredients. Omeprazole is contraindicated in patients taking cilostazol.

PBS listing

The 20 mg tablet strength is listed on the PBS with 8 items under streamlined and authority-required restrictions, with an ex-manufacturer price of A$10.65. The 10 mg tablet strength is listed on the PBS with 3 items under restricted access, with an ex-manufacturer price of A$3.50.

Regulatory history

LOSEC omeprazole 20 mg (as magnesium) and 10 mg (as magnesium) tablets were first registered on the ARTG on 14 December 1998.