Recovery of phenytoin from an enteral nutrient formula

Hooks, M.S.; Longe, R. Leon; Taylor, A. E.; Francisco, G. E.

doi:10.1093/ajhp/43.3.685

Cited by 14 publications

(13 citation statements)

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“…The continuous nasogastric (NG) administration of enteral nutrient formulas (ENFs), o r tube feedings, has been reported to lower steady-state serum PHT concentrations (Bauer, 1982;Hatton, 1984;Worden et al, 1984). The exact mechanism of this interaction is not known, though possible explanations include decreased bioavailability of the drug through changes in gastrointestinal motility (Yuen, 1984), binding of PHT to one or more components of ENFs (Yuen, 1984;Hooks et al, 1986), and adherence of P H T to the nasogastric tube (Cacek et al, 1986).…”

Section: Discussionmentioning

confidence: 99%

“…The affinity of PHT for serum proteins raises the possibility of binding to protein components in ENFs. Hooks et al (1986) compared the recovery of free PHT from a suspension product dispersed in Osmolite to the recovery from a control solution. Significantly less free drug was recovered from Osmolite in this in vitro study, suggesting that binding occurred.…”

Section: Discussionmentioning

confidence: 99%

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Effect of Two Administration Schedules of an Enteral Nutrient Formula on Phenytoin Bioavailability

Krueger¹,

Garnett²,

Comstock³

et al. 1987

Epilepsia

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Continuous nasogastric (NG) administration of enteral nutrient formulas (ENFs) reportedly lowers phenytoin (PHT) concentrations. We studied the effects of two administration schedules of an ENF on the bioavailability of PHT. Eight healthy volunteers received 400 mg PHT suspension after fasting (A), with hourly Ensure (B), and with 4-hourly Ensure (C) in a randomized, crossover design. Data obtained from 13 serum samples collected over 80 h were analyzed using ESTRIP. Area under the serum concentration-time curve (AUC), time to maximum serum concentration (Tmax), and urinary excretion of 5-(p-hydroxyphenyl) 5-phenylhydantoin (HPPH) were compared by analysis of variance (ANOVA) and Bonferroni t tests of differences between means. AUCs (mg x h/L) were not different (p greater than 0.05) for A (222.1 +/- 86.9), B (233.9 +/- 92.9), and C (226.0 +/- 95.7). Tmax (h) was significantly shorter (p less than 0.05) when PHT was administered with Ensure (B = 8.5 +/- 3.0, C = 5.3 +/- 2.0) than without Ensure (A = 18.5 +/- 10.5). The HPPH excretion (mg/80 h) was not different (p greater than 0.05) for A (225.6 +/- 48.5), B (238.6 +/- 26.6), and C (229.9 +/- 45.6). Clearance and maximum concentration correlated with AUC, obviating the need for analysis. Relative bioavailability was B/A = 1.07 +/- 0.21, C/A = 1.01 +/- 0.14. The bioavailability of PHT was not decreased by either ENF administration schedule. Factors other than direct contact may be responsible for the observed decreases in PHT concentrations by coadministered ENFs.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effect of Two Administration Schedules of an Enteral Nutrient Formula on Phenytoin Bioavailability

Krueger¹,

Garnett²,

Comstock³

et al. 1987

Epilepsia

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“…When changing these medications from their solid dosage forms to liquid, the schedule of the medication may need to be adjusted. For example, sustained release theophylline products given every [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] hours may need to be given every 6 hours.…”

Section: Drugs That Should Not Be Administered Through An Enteral Tubementioning

confidence: 99%

Considerations of Drug Therapy in Patients Receiving Enteral Nutrition

1989

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Some basic principles to consider in giving medications to patients receiving enteral nutrition include: 1. If the patient is able to take medication by mouth, this is the preferred route. 2. Liquid medications are the preferred dosage form. 3. The use of oral medications that are not meant to be crushed for enteral tube administration should be avoided. 4. For individual doses of most medications, the tube should be flushed with at least 30 ml of water before and after administration of medications. 5. Highly concentrated solutions should be diluted with 60 ml of water. 6. When several medications are to be administered to the same patient, all medications should be delivered separately and the tube flushed with at least 5 ml of water after each dose. 7. Medications should not be added directly to the feeding formulation. 8. Drug-nutrient interactions should be considered. 9. GI side effects are the most common adverse effects that occur with enteral feedings, and treatment depends on the cause.

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“…Hooks et al 7 describe the reduced recovery of phenytoin oral suspension dispersed in Osmolite 7 . The study examined how the recovery of phenytoin would be altered by either increasing the amount of phenytoin in a constant volume of Osmolite, or increasing the volume of Osmolite that contained a constant amount of phenytoin.…”

Section: Commentsmentioning

confidence: 99%