Section 1 - CHEMICAL PRODUCT AND COMPANY IDENTIFICATION

PRODUCT NAME

OMEPRAZOLE

NFPA

PRODUCT USE

Antiulcerative in the treatment of pathological hypersecretion (e.g. Zollinger- Ellison
syndrome). A substituted benzimidazole which does not exhibit anticholinergic or H2
histamine antagonist properties but suppresses gastric acid secretion by specific
inhibition of the H+/K+ ATPase enzyme system at the secretary surface of the gastric
parietal cell. Because this enzyme system is regarded as the acid (proton) pump within the
gastric mucosa, omeprazole has been characterised as a gastric- pump inhibitor.

SYNONYMS

C17-H19-N3-O3-S, "1H-benzimidazole, 5-methoxy-2-[((4-methoxy-3, 5-dimethyl-2-pyridinyl)-
", "1H-benzimidazole, 5-methoxy-2-[((4-methoxy-3, 5-dimethyl-2-pyridinyl)-",
methyl]sulfinyl-, "5-methoxy-2-[((4-methoxy-3, 5-dimethyl-2-pyridyl)methyl)sulfinyl]-",
"5-methoxy-2-[((4-methoxy-3, 5-dimethyl-2-pyridyl)methyl)sulfinyl]-", benzimidazole,
Antra, Audazol, AULCER, Belmazol, Ceprandol, Elgam, Emeproton, Gastrimut, Gastroloc, H-
168/68, Indurgan, Losec, Miol, Mepral, Mopral, Omapren, Omepral, Omeprazole, Ompanyt,
Parizac, Pepticum, Prilosec, Prysma, Sanamidol, Secrepina, Ulceral, Ulcsep, Ulcometion,
Zimor, "gastrointestinal agent/ gastric proton-pump inhibitor", anti-ulcerative

Section 2 - HAZARDS IDENTIFICATION

CANADIAN WHMIS SYMBOLS

EMERGENCY OVERVIEW

RISK

May cause long- term adverse effects in the aquatic environment.

POTENTIAL HEALTH EFFECTS

ACUTE HEALTH EFFECTS

SWALLOWED

  Although ingestion is not thought to produce harmful effects, the material may still be damaging to the health of the individual following ingestion, especially where pre-  existing organ (e.g. liver, kidney) damage is evident. Present definitions of harmful or toxic substances are generally based on doses producing mortality (death) rather than those producing morbidity (disease, ill-health). Gastrointestinal tract discomfort may produce nausea and vomiting. In an occupational setting however, ingestion of insignificant quantities is not thought to be cause for concern.  Limited evidence exists that the substance may cause irreversible but non-lethal mutagenic effects following a single exposure.  

EYE

  Although the material is not thought to be an irritant, direct contact with the eye may cause transient discomfort characterized by tearing or conjunctival redness (as with windburn). Slight abrasive damage may also result. The material may produce foreign body irritation in certain individuals.  

SKIN

  The material is not thought to produce adverse health effects or skin irritation following contact (as classified using animal models). Nevertheless, good hygiene practice requires that exposure be kept to a minimum and that suitable gloves be used in an occupational setting.  Open cuts, abraded or irritated skin should not be exposed to this material.  Entry into the blood-stream, through, for example, cuts, abrasions or lesions, may produce systemic injury with harmful effects. Examine the skin prior to the use of the material and ensure that any external damage is suitably protected.  

INHALED

  The material is not thought to produce adverse health effects or irritation of the respiratory tract (as classified using animal models). Nevertheless, good hygiene practice requires that exposure be kept to a minimum and that suitable control measures be used in an occupational setting.  Persons with impaired respiratory function, airway diseases and conditions such as emphysema or chronic bronchitis, may incur further disability if excessive concentrations of particulate are inhaled.  

CHRONIC HEALTH EFFECTS

  There has been some concern that this material can cause cancer or mutations but there is not enough data to make an assessment.  Limited evidence suggests that repeated or long-term occupational exposure may produce cumulative health effects involving organs or biochemical systems.  There is limited evidence that, skin contact with this product is more likely to cause a sensitization reaction in some persons compared to the general population.  Exposure to the material may result in a possible risk of irreversible effects. The material may produce mutagenic effects in man. This concern is raised, generally, on the basis ofappropriate studies with similar materials using mammalian somatic cells in vivo. Such findings are often supported by positive results from in vitro mutagenicity studies.  The use of gastric proton pump inhibitors (antiulceratives) has been associated with the induction of carcinoid-like tumours of the gastric mucosa. This is thought to be associated with a complete block of gastric acid secretion leading to hypergastrinaemia and hyperplasia of enterochromaffin-like cells. As a result, the therapeutic use of these inhibitors is generally restricted.  A number of benzimidazoles have been shown to also inhibit mammalian tubulin polymerisation and to be aneugenic in vivo. Aneugens affect cell division and the mitotic spindle apparatus resulting in loss or gain of whole chromosomes, thereby inducing an "aneuploidy". Mitotic aneuploidy is a characteristic of many types of tumorigenesis (in cancer). Several benzimidazoles have been shown to be genotoxic. Genotoxicity may arise as aneugens may also be clastogens, or may produce clastogenic metabolites. Clastogens increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.  In two 24-month carcinogenicity studies in rats, the drug (given at 4-352 times the human dosage) produced gastric ECL cell carcinoids in a dose-related manner in both male and female rats ECL cell hyperplasia was present in all treatment groups. A 78-week mouse carcinogenicity study did  not show increased tumor occurrence.  Omeprazole was not mutagenic in an in vitro Ames Salmonella typhimurium assay, an in vitro mouse lymphoma cell assay and an in vivo liver DNA damage assay. A mouse micronucleus test at 625 and 6250 times the human dose gave a borderline result, as did an in vivo bone marrow chromosome aberration test.  In developmental studies with rabbits (at 17-172 times the human dose) the drug produced dose-related increases in embryo-lethality, foetal resorptions, and pregnancy disruptions. In rats. dose-related embryo/foetal toxicity and post-natal developmental toxicity was seen in offspring of  parents treated with 13-138 times the human dose. Sporadic reports have been received of congenital abnormalities occurring in infants born to woman receiving the drug during pregnancy.