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Gastric function in the elderly: effects on absorption of ketoconazole
Aryeh Hurwitz1, Constance E Ruhl, Bruce F Kimler
1Department of Internal Medicine, Division of Clinical Pharmacology, Room 4016 Wescoe, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160-7320, USA.
Journal of Clinical Pharmacology
|September 16, 2003
Summary
Elderly individuals with normal gastric function absorb ketoconazole well. However, reduced stomach acidity (higher pH) can impair ketoconazole absorption from intact tablets, but not crushed ones.
Area of Science:
- Pharmacokinetics
- Gastroenterology
- Geriatrics
Background:
- Age-related changes in gastric function can affect drug absorption.
- Ketoconazole absorption is pH-dependent, requiring an acidic environment.
Purpose of the Study:
- To investigate the impact of age-related gastric changes on ketoconazole absorption.
- To determine if reduced gastric acidity affects ketoconazole bioavailability in the elderly.
Main Methods:
- Eighteen elderly participants (≥65 years) received ketoconazole (200 mg) orally, with intact or crushed tablets.
- Gastric pH was monitored via radiotelemetry; gastric emptying and plasma ketoconazole levels (HPLC) were measured.
Main Results:
- Ketoconazole absorption was similar for intact and crushed tablets when gastric pH ≤ 4.5.
- When gastric pH was ≥ 5.0, absorption was adequate from crushed tablets but significantly reduced from intact tablets.
- Gastric emptying was rapid in all subjects.
Conclusions:
- Impaired ketoconazole absorption in the elderly is uncommon with normal gastric function.
- Reduced gastric acidity (hypoacidity) may necessitate using crushed formulations for optimal absorption in affected individuals.