Dec 27, 1969

Steady-state plasma levels of nortriptyline in twins: influence of genetic factors and drug therapy

British Medical Journal
B AlexandersonF Sjöqvist

Abstract

Nineteen identical (monozygotic) and 20 fraternal (dizygotic) sets of twins between 45 and 51 years of age were given nortriptyline orally in doses of 0.2 mg./kg. body weight three times daily for eight days. The steady-state plasma concentrations of nortriptyline were calculated from the mean of the determinations for days 6, 7, and 8. Identical twins, not treated with other drugs, achieved similar steady-state plasma concentrations of nortriptyline in contrast to fraternal twins who were not given other drugs. The intrapair similarity in steady-state plasma concentrations was not found in identical twins simultaneously treated with various drugs during the experiment. Identical and fraternal twins treated with drugs containing barbiturates had considerably lower steady-state plasma concentrations of nortriptyline compared with untreated twins.It is concluded that most of the variability in nor-triptyline steady-state plasma concentration between persons who have not received drugs is genetically determined. Exposure to other drugs also influences the steady-state plasma concentration of nortriptyline, which in a given patient may therefore be determined by a resultant of genetic and environmental factors.

Mentioned in this Paper

Medical Genetics Specialty
Weighing Patient
Nortriptyline Assay
Barbiturates Measurement
Twin Sibling
Exogenous Factors
Barbiturates
Oral Cavity
Norfenazin
Nortriptyline

About this Paper

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