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Age and nortriptyline concentrations in plasma ultrafiltrate
1The New York Presbyterian Hospital, Westchester Division, White Plains, New York, USA.
International Journal of Geriatric Psychiatry
|December 13, 2000
Summary
Older patients have lower ultrafiltrate nortriptyline (NT) concentrations, suggesting reduced tissue exposure. This finding is crucial for understanding nortriptyline
Area of Science:
- Pharmacology
- Geriatric Medicine
- Psychiatry
Background:
- Plasma protein binding of tricyclic antidepressants (e.g., nortriptyline) may influence treatment outcomes.
- Age-associated factors can affect drug binding and concentrations.
Purpose of the Study:
- To examine the relationship between age and both plasma ultrafiltrate and total concentrations of nortriptyline (NT).
- To investigate the ratio of ultrafiltrate NT to total plasma NT in relation to age.
Main Methods:
- Studied 87 patients with major depression on stable nortriptyline doses.
- Measured trough plasma ultrafiltrate and total NT concentrations using high-performance liquid chromatography.
- Corrected NT concentrations for administered dose.
Main Results:
- Ultrafiltrate NT concentrations showed a significant negative association with age.
- The ratio of ultrafiltrate NT to total NT also decreased significantly with age.
- Total plasma NT concentrations did not show a significant association with age.
Conclusions:
- Older patients exhibit lower ultrafiltrate NT concentrations, potentially indicating reduced tissue drug exposure.
- These age-related differences in unbound NT may be relevant to both therapeutic and toxic effects.
- Further research is needed to explore the link between unbound drug concentrations and nortriptyline treatment outcomes across different age groups.