Sex-specific differences in plasma levels of Venlafaxine and Risperidone

Status

Active, not recruiting

Phases

Unknown

Study type

Observational

Source

DRKS

Registry ID

DRKS00040424

Enrollment

200

Registered

2026-05-27

Start date

2024-01-04

Completion date

Unknown

Last updated

2026-06-01

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

F20-F29 F30-F39

Interventions

Group 1: This study focuses on interpreting the correlation between daily dose and serum levels of the two medications, venlafaxine and risperidone, as well as gender-specific differences in these lev

Eligibility

Sex/Gender

All

Age

18 Years to 75 Years

Inclusion criteria

Inclusion criteria: - Inpatient or day-care treatment at the Department of Psychiatry and Psychotherapy III at Ulm University Hospital (including all wards and the day clinic) - Minimum stay of 7 days at the clinic - Oral administration of venlafaxine or risperidone as part of medication therapy - Verbal and written consent to participate in the study

Exclusion criteria

Exclusion criteria: - Severe pre-existing conditions such as liver cirrhosis or kidney disease requiring dialysis - Concomitant use of medications that affect CYP2D6 - Patients unable to provide informed consent, for example due to severe cognitive impairments or acute psychotic states - Age under 18 or over 75 - Transsexuality, as hormonal factors could influence pharmacokinetics - Insufficient knowledge of German, making communication regarding the study content and consent impossible - Lack of written and verbal consent to participate in the study prior to the start of data collection

Design outcomes

Primary

Measure	Time frame
The study was conducted over a 12-month period from January 1, 2024, to December 31, 2024. All patients receiving risperidone or venlafaxine who were hospitalized or receiving outpatient care in the Department of Psychiatry III at the University Hospital of Ulm during this period and who met the inclusion criteria were enrolled in the study. Blood level measurements of the two psychotropic drugs, risperidone and venlafaxine, were performed. For this purpose, approximately 2 mL of blood was collected in an EDTA tube. These blood draws were performed at steady state. For venlafaxine, steady state is reached 25 hours after the last dose; for risperidone, 15 hours after the last dose. The time of the last dose and the time of blood collection were documented. The plasma levels of venlafaxine were analyzed in the laboratory using mass spectrometric analysis. EDTA-anticoagulated plasma served as the sample material. The samples were first prepared using a protein precipitation method. This was followed by chromatographic separation of the analytes using high-performance liquid chromatography (HPLC). Detection of the target substances was performed using a triple-quadrupole tandem mass spectrometer. Ionization of the analytes was carried out via electrospray ionization (ESI). If these measurements could not be performed within 48 hours, the samples were frozen at -20°C. All concentration measurements were performed exclusively in the Department of Clinical Chemistry at the University Hospital Ulm laboratory and are therefore comparable. The concentrations of the active ingredients (risperidone/venlafaxine) and their metabolites (paliperidone/desmethylvenlafaxine) were measured. According to the 2017 consensus, the evaluation of the concentration measurements is performed as follows: 10 The starting point is the determination of the so-called metabolic ratio, the ratio of the parent compound to its metabolite. It is calculated as the quotient of the metabolite and the par	—

Measure

Time frame

The study was conducted over a 12-month period from January 1, 2024, to December 31, 2024. All patients receiving risperidone or venlafaxine who were hospitalized or receiving outpatient care in the Department of Psychiatry III at the University Hospital of Ulm during this period and who met the inclusion criteria were enrolled in the study. Blood level measurements of the two psychotropic drugs, risperidone and venlafaxine, were performed. For this purpose, approximately 2 mL of blood was collected in an EDTA tube. These blood draws were performed at steady state. For venlafaxine, steady state is reached 25 hours after the last dose; for risperidone, 15 hours after the last dose. The time of the last dose and the time of blood collection were documented. The plasma levels of venlafaxine were analyzed in the laboratory using mass spectrometric analysis. EDTA-anticoagulated plasma served as the sample material. The samples were first prepared using a protein precipitation method. This was followed by chromatographic separation of the analytes using high-performance liquid chromatography (HPLC). Detection of the target substances was performed using a triple-quadrupole tandem mass spectrometer. Ionization of the analytes was carried out via electrospray ionization (ESI). If these measurements could not be performed within 48 hours, the samples were frozen at -20°C. All concentration measurements were performed exclusively in the Department of Clinical Chemistry at the University Hospital Ulm laboratory and are therefore comparable. The concentrations of the active ingredients (risperidone/venlafaxine) and their metabolites (paliperidone/desmethylvenlafaxine) were measured. According to the 2017 consensus, the evaluation of the concentration measurements is performed as follows: 10 The starting point is the determination of the so-called metabolic ratio, the ratio of the parent compound to its metabolite. It is calculated as the quotient of the metabolite and the par

—

Countries

Germany

Contacts

Public ContactCarlos Schönfeldt-Lecuona

Klinik für Psychiatrie & Psychotherapie III Universitätsklinikum Ulm

carlos.schoenfeldt@uni-ulm.de+491637151488

Outcome results

None listed

Source: DRKS (via WHO ICTRP) · Data processed: Jun 11, 2026