Comparison of the Pharmacokinetics of Two Generic Antidepressants and Their Respective Brand Preparations

University of Ottawa

Status and phase: Completed; Phase 1

Conditions: Healthy

Treatments: Drug: Celexa; Drug: Effexor XR; Drug: Venlafaxine; Drug: Gen-Citalopram

Study type: Interventional

Funder types: Other

Identifiers

NCT00676039

REB-2007024

Details and patient eligibility

About

Generic medications should be the equivalent of brand medications with the exception of their price. Before a generic medication is introduced, its bioequivalence within a window of 80 to 125% of the original has to be demonstrated. There are reports that this criterion is not always followed in post-marketed periods. Such investigations were triggered by the observation that some patients previously stable on original medications relapsed when switched to a presumable equivalent generic. Several factors could account for this problem. Given reports of such problems occurring with the antidepressants citalopram and venlafaxine, some pharmacokinetic properties of specific brands of generics and the originals will be examined for these two medications. Twelve healthy male volunteers will participate in this crossover study. It is anticipated that there will be significant differences emerging between the two formulations given the clinical reports of patients deteriorating when switched from the original to the generic preparations.

Enrollment: 18 patients

Sex: Male

Ages: 18 to 50 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Healthy volunteers (absence of diseases: psychiatric, physical, neurological, metabolic,...)

Exclusion criteria

• Psychiatric disorder
• Hepatic disease
• Renal disease
• Gastrointestinal disease
• Hematological disease
• Smokers
• Physical and/or neurological disease
• Positive urine drug screen
• Abnormal blood pressure
• Abnormal urine/blood analysis (sodium, potassium, chloride, creatinine, urea, ALT, AST, total protein, glucose, and TSH)

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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18 participants in 2 patient groups

1

Active Comparator group

Description:

Crossover Effexor / NOVO-Venlafaxine Examination of the bioequivalence of Effexor (Wyeth Pharmaceuticals) and NOVO-Venlafaxine (NOVOPHARM). Both drugs will be given at the dose of 75 mg/day (one capsule per day) for 4 consecutive days. A washout period (corresponding to 10 half-life of the active metabolite desmethylvenlafaxine) will be respected after receiving each medication.

Treatment:

Drug: Effexor XR

Drug: Venlafaxine

2

Active Comparator group

Description:

Crossover Celexa/Gen-citalopram Examination of the bioequivalence of Celexa (Lundbeck, Brand Name) and Gen-Citalopram (Genpharm, Generic). Both drugs will be given at the dose of 40 mg/day (one tablet per day) for 8 consecutive days. A washout period (corresponding to 10 half-life of citalopram) will be respected after receiving each medication.

Treatment:

Drug: Gen-Citalopram

Drug: Celexa