In: Main14 Apr 2010
Like the delayed-release, enteric-coated, oral PPI formulations, IR-OME may prolong the elimination of drugs that are metabolized by oxidation in the liver, such as diazepam (Valium, Roche), (Coumadin candian, Bristol-Myers Squibb), and (Pfizer). Increased International Normalized Ratios (INRs) and prothrombin times have been reported in patients receiving concomitant warfarin and omeprazole therapy. These increases may lead to abnormal bleeding and possibly death. Therefore, patients taking canadian warfarin and omeprazole concomitantly should be monitored closely for INRs and pro-thrombin times.
In studies of once-daily omeprazole 40 mg and (e.g., Abbott) 500 mg every eight hours administered to healthy men, the steady-state plasma concentrations of omepra-zole were increased: the Cmax by 30%, the AUC0-24 by 89%, and the half-life by 34%).
As summarized in Table 1, IR-OME is indicated for the short-term treatment (four to eight weeks) of active duodenal ulcer, heartburn, and other symptoms associated with GERD; the short-term treatment of erosive esophagitis, as diagnosed by endoscopy; the maintenance of healing of erosive esophagitis (studies do not extend beyond 12 months); and the short-term treatment of active benign gastric ulcer. This is the only PPI to date that is indicated for lowering the risk of upper GI bleeding in critically ill patients and for nasogastric and/or orogastric tube administration.
DOSAGE AND ADMINISTRATION
The recommended dose of IR-OME is 40 mg or 20 mg, based upon the indication, to be taken once daily on an empty stomach at least one hour before a meal. When taken at bedtime, it reduces nocturnal gastric acidity to an extent that has not been observed with once-daily dosing of delayed-release PPIs.
Dosage modification is generally not needed in elderly patients or in those with mild-to-moderate renal or hepatic impairment.
The IR formulation is currently available as a peach-mint flavored powder for oral suspension in 40- and 20-mg packets. Because of this product’s unique phar-macokinetic profile, there are no therapeutic equivalents, and it is not AB-rated compared with delayed-release (Prilosec OTC).
The oral suspension offers an alternative for patients (e.g., elderly people and children) who require PPI therapy for acid-related conditions but who have difficulty swallowing tablets or capsules. Absorption is optimized when patients take this product on an empty stomach at least one hour before a meal. For the control of nighttime gastric acidity, however, the effect is greatest when it is taken at bedtime on an empty stomach.
Patients should be instructed to pour a packet of the powder for oral suspension into a small cup containing one to two tablespoons (15-30 ml) of water, to stir well, and to drink immediately. No other liquids or foods should be mixed with the powder. The cup should be refilled with an additional small amount of water, and this should also be consumed right away to ensure that a complete dose is ingested.
For patients with nasogastric or oro-gastric tubes, the powder should be constituted with approximately 15 to 30 ml of water (0.5-1.0 fluid ounce). Other liquids or foods should not be used. The suspension should be stirred well and administered immediately, and a syringe of the appropriate size should be used to instill the suspension in the tube. The suspension should be washed through the tube with an additional 20 ml of water.
The FDA is currently reviewing 40-mg and 20-mg IR-OME capsules and IR-OME chewable tablets.
The unique “non-enteric” formulation of IR-OME provides more rapid absorption and decreased time to peak plasma concentrations than do enteric-coated, delayed-release PPIs. These pharmaco-kinetic properties may confer advantages for patients with acid-related disorders, as suggested by emerging data about the product’s effectiveness in controlling nocturnal gastric pH in symptomatic GERD patients and its ability to control gastric acidity in critically ill patients.
Oral IR-OME, when taken on an empty stomach at bedtime, is effective in controlling nocturnal gastric acidity. It is an alternative to the use of IV acid-suppressant therapy for attaining and sustaining a gastric pH above 6 and for lowering the risk of upper GI bleeding in critically ill patients.
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