BRANDED VS. GENERIC CLOZAPINE FOR TREATMENT OF SCHIZOPHRENIA
Makela EH, Cutlip WD II, Stevenson JM, et al. Ann Pharmacother. 2003;37:350-353.
Background
Despite the cost savings associated with generic substitution, some physicians have been hesitant to prescribe generic clozapine. Concerns have been expressed about the validity of bioequivalence studies conducted in healthy volunteers at doses lower than those used to treat patients with schizophrenia.1,2
This independent “switch” study was conducted to address some of these issues.
- The subjects were patients with schizophrenia
- The dosage of generic clozapine was the same as the dosage of Clozaril
- Patients were evaluated based upon symptomatology
- The generic clozapine product was manufactured by Mylan Pharmaceuticals
Although this study has a number of limitations, the results suggest that patients treated with Clozaril can be effectively switched to The Mylan Brand of Clozapine. Additional studies will need to address the same endpoint.
Due to lack of optimal study controls and small sample size, the results should be interpreted cautiously.
Objective
- To report clinical findings resulting from a switch from Clozaril®* to The Mylan Brand of Clozapine
Methods
- The Mylan Brand of Clozapine was chosen because it offered a monitoring system with numerous advantages, including a secured web page, access to historical white blood cell count, absolute neutrophil cell count, and reports designed to enhance patient safety
- Twenty patients at a Thought Disorders Clinic agreed to switch from their current medication (Clozaril) to The Mylan Brand of Clozapine at the same dosage
- All patients were stable with no recent history of hospitalization
- The patients were evaluated at baseline and 2-4 months after the switch using the Positive and Negative Syndrome Scale (PANSS)3 measure of overall symptomatology
- The Beck Anxiety Inventory (BAI) was used to assess anxiety surrounding the switch to a generic product
- The Abnormal Involuntary Movement Scale (AIMS) and The Movement Disorder Assessment (MDA) were used to detect extrapyramidal symptoms (EPS)
- The paired t-test was used to detect differences in rating scale measures
Results
- Based upon statistical analyses, no significant differences were noted between branded and generic clozapine for the total PANSS; the positive symptom, negative symptom, and general psychopathology subscales of the PANSS; and the BAI
- There were no significant differences in adverse effects as detected on the AIMS or MDA rating scales
Conclusions
- In 20 patients with schizophrenia, there was no deterioration in clinical status after changing from Clozaril to The Mylan Brand of Clozapine in a normal routine clinical setting
- This finding is consistent with pharmacologic data suggesting bioequivalence of the two products
- Results must be interpreted cautiously due to the lack of optimal study controls and small sample size
- Despite these limitations, this investigation, carried out in a naturalistic setting, demonstrates the feasibility of critically assessing outcomes in a clinic population resulting from a comprehensive alteration in pharmacologic treatment
Agranulocytosis, granulocytopenia, seizures, orthostatic hypotension, tachycardia, drowsiness, and dizziness have been reported in patients taking clozapine. For more information, please review the full Prescribing Information, which includes BOXED WARNINGS.
* Registered trademark of Novartis Pharmaceuticals Corporation.
References: 1. Meyer MC. United States Food and Drug Administration requirements for approval of generic drug products. J Clin Psychiatry. 2001;62(suppl 5):4-9. 2. Kluznik JC, Walbek NH, Farnsworth MG, Melstrom K. Clinical effects of a randomized switch of patients from Clozaril to generic clozapine. J Clin Psychiatry. 2001;62(suppl 5):14-17. 3. Kay SR, Fiszbein A, Opler LA. The positive and negative syndrome scale (PANSS) for schizophrenia. Schizophr Bull. 1987;13:261-276.
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