Pharmacy & Therapeutics - March 2009 - (Page 150) PPIs in Enteral Nutrition including patients who tolerated tube feedings and by excluding patients with delayed gastric emptying or ileus.22 The appropriate functioning and motility of the GI tract in these patients might have allowed for the timely passage of the medication into the small bowel. Lansoprazole Sharma et al.26,27 Pantoprazole Ferron et al.23 Although current manufacturer recommendations are available for administering pantoprazole oral suspension packets, none exist for the tablet.9 Ferron et al. sought to compare the bioavailability of pantoprazole tablets with that of an oral suspension administered via a nasogastric tube (see Table 3). This crossover trial included 12 healthy males. A pharmacokinetic analysis found that although the Cmax was similar for both formulations, the bioavailability was significantly lower for the suspension: tablet AUC = 6.53; suspension AUC = 4.89 (P < 0.001). The authors noted that the reduced bioavailability might have been caused by the lower concentration of sodium bicarbonate used (i.e., 4.2% vs. 8.4% used for other PPIs), thus allowing for premature activation of the medication. GASTROSTOMY TUBES Omeprazole Various formulations of omeprazole have been evaluated for administration via gastrostomy tubes. Sharma et al.24,25 Sharma et al. evaluated omeprazole given by gastrostomy tube using intact granules suspended in orange juice.24 In this open-label study, 14 male patients received 20 mg of omeprazole for seven days. Mean baseline 24-hour intragastric pH was 1.8, which rose to 4.9 after seven days of therapy with the omeprazole suspension (P < 0.0001). The proportion of time the intragastric pH was above 3 was also measured during the baseline and post-therapy 24-hour periods. At baseline, the mean time at a pH above 3 was 21%; after treatment, this proportion rose to 80% (P < 0.0001).24 In another study, Sharma and other colleagues also evaluated the use of a simplified omeprazole suspension (omeprazole granules suspended in sodium bicarbonate) in a similar patient population.25 This open-label study was much smaller, with only six patients, and consisted of only male patients treated with 20 mg of omeprazole for seven days. The mean baseline 24-hour intragastric pH was 2.2 and rose to 4.1 after seven days of the omeprazole suspension (P < 0.01). The authors also measured the proportion of time during which the intragastric pH was above 3, 4, and 5 during the baseline and post-therapy 24-hour periods. At the baseline examination, the proportions of time during which patients’ pH was above 3, 4, and 5 were 35%, 28%, and 17%, respectively. After treatment, these values rose to 63%, 51%, and 39% for a pH above 3, 4, and 5, respectively (P 0.05).25 Sharma and colleagues also studied the effect of lansoprazole on pH when the drug was suspended in orange juice.26 Using an identical study design as in the other trials just described,24,25 the investigators found that lansoprazole was effective as a suspension in orange juice. Eight men received lansoprazole 30 mg for seven days. The mean 24-hour baseline pH was 1.9, which rose to 4.7 after therapy was completed (P < 0.0001). At the baseline evaluation, the proportion of time spent at a pH above 3, 4, and 5 was 23%, 13.5%, and 7.5%, respectively. After treatment, time proportions at a pH above 3, 4, and 5 rose to 81%, 70%, and 52%, respectively (P < 0.0001).26 In an open-label study, Sharma and associates also assessed the use of a simplified lansoprazole suspension administered by gastrostomy tube.27 This study compared lansoprazole suspended in orange juice with a solution of lansoprazole made with sodium bicarbonate in six male patients. The patients first received lansoprazole in orange juice for seven days, followed by a lansoprazole suspension for seven days. The mean 24-hour baseline pH of 1.8 rose to 4.5 after seven days of lansoprazole in orange juice and to 5.1 after seven days of the suspension. Significant changes were found for each formulation compared with baseline (P 0.05). The proportion of time at a pH exceeding 3, 4, and 5 also differed significantly for both formulations compared with baseline (P 0.05).27 Esomeprazole Several in vitro studies have examined the deliver y of esomeprazole pellets via nasogastric and gastrostomy tubes. Shah et al.28; Johnson29 Shah et al. compared delivery of esomeprazole magnesium enteric-coated pellets in tap water with various concentrations of the suspension liquid, Ora-Plus (Paddock Laboratories),28 a vehicle used for extemporaneous compounds.29 In the first phase of the study, the authors used size 14 French standard nasogastric tubes to deliver esomeprazole pellets in tap water (Ora-Plus 30%, Ora-Plus 50%, and Ora-Plus 70%). After phase 1, pellet retention was significantly greater with Ora-Plus 70% (P 0.280) or the gastrostomy tubes (P > 0.886). During both phases, all methods were successful in delivering the dispersed pellets at a rate of 99%; however, during phase 2, one trial was excluded from analysis because of exceptionally large pellet retention with the use of tap water in a size 8 French nasogastric tube. The authors attributed this effect to the ever-present potential for clogging when drugs are given by a feeding tube.28 150 P&T® • March 2009 • Vol. 34 No. 3
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