SOMAC

What it is

SOMAC is pantoprazole sodium, supplied as a powder for injection containing 42.3 mg pantoprazole sodium equivalent to 40 mg pantoprazole per vial. Pantoprazole is a proton pump inhibitor that inhibits specifically and dose-proportionately H+/K+-ATPase, the enzyme responsible for gastric acid secretion in the parietal cells of the stomach.

Approved indications

SOMAC is indicated for short-term use where oral therapy is not appropriate for symptomatic improvement and healing of gastrointestinal diseases which require a reduction in acid secretion, including: — Duodenal ulcer — Gastric ulcer — Reflux oesophagitis — Gastrointestinal lesions refractory to H₂ blockers — Zollinger-Ellison Syndrome SOMAC is also indicated for maintenance of healed reflux oesophagitis in patients previously treated for moderate to severe reflux oesophagitis.

Dosing overview

Intravenous SOMAC should be replaced with oral therapy as soon as practicable. After preparation, the solution should be administered over 2 to 15 minutes.

Key safety warnings

In the presence of alarm symptoms such as significant unintentional weight loss, recurrent vomiting, dysphagia, haematemesis, anaemia or melaena, and when gastric ulcer is suspected or present, malignancy should be excluded, as treatment with pantoprazole may alleviate symptoms and delay diagnosis. Proton pump inhibitor therapy may be associated with an increased risk of Clostridium difficile infection. Pantoprazole, like all proton pump inhibitors, might increase the counts of bacteria normally present in the upper gastrointestinal tract and may lead to a slightly increased risk of gastrointestinal infections caused by bacteria such as Salmonella, Campylobacter and Clostridium difficile. Severe cutaneous adverse reactions, including erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms, and acute generalised exanthematous pustulosis have been reported in association with the use of proton pump inhibitors. Discontinue pantoprazole at the first signs or symptoms of severe cutaneous adverse reactions or other signs of hypersensitivity. Proton pump inhibitor therapy may be associated with an increased risk for osteoporosis-related fractures of the hip, wrist or spine, particularly in patients who received high-doses defined as multiple daily doses and long-term therapy of a year or longer. Acute interstitial nephritis has been observed in patients taking proton pump inhibitors including pantoprazole and may occur at any point during therapy. Discontinue pantoprazole if acute interstitial nephritis develops.

Contraindications

SOMAC is contraindicated in patients with known hypersensitivity to pantoprazole, substituted benzimidazoles or any other components of the formulation, or in cases of cirrhosis or severe liver disease. Pantoprazole should not be co-administered with HIV protease inhibitors such as atazanavir or nelfinavir.

PBS listing

SOMAC tablet (enteric coated) 20 mg is listed on the PBS with a restriction and ex-manufacturer price of A$7.12. SOMAC tablet (enteric coated) 40 mg is listed with streamlined authority required restriction and ex-manufacturer price of A$7.48. SOMAC sachet containing granules 40 mg is listed with streamlined authority required restriction and ex-manufacturer price of A$19.64.

Regulatory history

SOMAC pantoprazole 40 mg powder for injection was first listed on the Australian Register of Therapeutic Goods on 22 December 2006. In November 2017, the Pharmaceutical Benefits Scheme Advisory Committee recommended an amendment to the current PBS listing to allow pantoprazole to be used for the treatment of gastro-oesophageal reflux disease in adult and paediatric patients.