(for veterinary information only)

BRAND NAME: PRILOSEC, GASTROGARD

AVAILABLE IN ORAL PASTE or SUSTAINED RELEASE CAPSULES (10 mg, 20 mg, 40 mg)

BACKGROUND

The quest for medications against nausea and upset stomach is on-going in both human and veterinary medicine. In the past, antacids started as simple alkaline products that one swallowed to neutralize stomach acid. As the production of stomach acids came to be better understood, antacids that interfered with acid production were developed. The H2 blocking drugs were developed next. These blocked H2 receptors, special receptors for histamine in the stomach that when stimulated would cause stomach acid production. Blocking the receptor meant blocking acid production. Cimetidine (Tagamet®) was the first of these followed by ranitidine (Zantac®) and famotidine (Pepcid AC ®). There are other receptors involved in stomach acid secretion stimulation besides H2 receptors so even with H2 receptors blocked, acid could still be secreted.

Omeprazole represents a different tact: proton pump inhibition. The quantity of acid ultimately amounts to the quantity of protons. The proton pump is central to secreting acid into the stomach and with this pump inhibited, stomach acid production is halted. Proton pump inhibitors like omeprazole are the strongest antacids of all. It works not only when the stomach is full/digesting food but all the time.

HOW THIS MEDICATION IS USED

Omeprazole is used in the treatment of stomach ulcers or in the prevention of stomach ulcers. It is generally used once a day.

SIDE EFFECTS

Increases in liver enzymes may be induced by the use of omeprazole. This is not harmful but should be recognized as an omeprazole reaction should it be seen on a blood test.

Bone marrow suppression has been noted as an occasional reaction to this medication in humans.

Omeprazole is able to reduce cerebrospinal fluid production though it is not known how.

INTERACTIONS WITH OTHER DRUGS

Omeprazole inhibits a system of liver enzymes called the “cytochrome p450 system.” Many other drugs depend on this system for removal. This means that if omeprazole is used, the following drugs will last longer and work more strongly: Diazepam (valium®), phenytoin (used to treat both seizures and heart rhythm disturbances), and warfarin (a blood thinning agent).

Because omeprazole reduces stomach acid, other drugs that require an acid environment for absorption into the body may not be as well absorbed. Such drugs include ketoconazole (an antifungal agent), and some forms of ampicillin (an antibiotic).

In humans, omeprazole has occasionally suppressed bone marrow. This effect could be enhanced if other marrow suppressing drugs (such as methimazole or agents of chemotherapy) are used concurrently.

CONCERNS AND CAUTIONS

Omeprazole should be stored at room temperature in a light-tight container.

If the pet is reluctant to swallow the capsules, do not attempt to crush the pellets inside the capsules and add them to water to food. It is permissible to add them to fruit juice, however.

Omeprazole is removed from the body by both the liver and kidneys. The dosage of omeprazole should be altered if the patient suffers from either liver or kidney insufficiency.

Safety of the use of this medication in lactation or pregnancy has not been established.