Comparación farmacocinética de Sinemet y Grifoparkin (levodopa/carbidopa 250/25 mg) en pacientes con enfermedad de Parkinson avanzada: un estudio con dosis única / Pharmacokinetic comparison of Sinemet and Grifoparkin (levodopa/carbidopa 250/25 mg) in Parkinson s disease: a single dose study

BACKGROUND: There are doubts wether generic medications have the same bioavailability and efficacy compared with the original drugs developed by pharmaceutical companies with research capabilities. AIM: To compare the pharmacokinetics and clinical (motor) responses of Sinemet and Grifoparkin (generic carbidopa/levodopa 250/25 mg) in patients with advanced Parkinson's disease. PATIENTS AND METHODS: Patients were randomly assigned to Sinemet (15 patients 62 +/- 12 years old; mean disease duration 11 +/- 7 years) or Grifoparkin (15 patients, 64 +/- 11 years old; mean disease duration 12 +/- 4 years) groups. Medication and food were withheld 12 h before the study. Fifteen blood samples were collected (starting 9 AM) immediately before (sample 1, t = 0 min) and after (samples 2-15, t = 20-360 min) oral administration of a single dose of Sinemet or Grifoparkin, and plasmatic L-DOPA was quantified using HPLC with electrochemical detection. Additionally, each patient was clinically evaluated every 20 minutes, using the tapping test and the unified Parkinson's disease scale Hoehn & Yarh. RESULTS: Tmax (time at which the maximal L-DOPA concentration was reached) were 69 +/- 12 min and 64 +/- 11 min for Sinemet and Grifoparkin respectively (NS). Cmax (maximal L-DOPA concentration reached) was 3161 +/- 345 ng/ml for Sinemet and 3274 +/- 520 ng/ml for Grifoparkin (NS). The t1/2 (half life time), CL (clearance) and volume of distribution (Vd) values calculated were 159 +/- 32 min, 51.7 +/- 5.1 1/h and 3.6 +/- 1.2 l/kg for Sinemet and 161 +/- 48 min, 58.7 +/- 8 l/h and 3.0 +/- 0.7 l/kg for Grifoparkin (NS). UPDRS-III value for the best on state and for the worst off state were 23 +/- 11 and 50 +/- 19 for Sinemet and 20 +/- 7 and 46 +/- 13 for Grifoparkin respectively (NS). CONCLUSION: The results obtained showed that both drugs are bioequivalent in patients with advanced Parkinson's disease.

Complicaciones motoras precoces en parkisonianos de novo tratados con L-Dopa más inhibidor periférico de la decarboxilasa / Early motor complications in parkisonians of novo treated with L-Dopa plus descarboxylase inhibitor

En una serie de 27 pacientes con enfermedad de Parkinson esencial de novo, en grado 2,7 de Hoehn y Yahr como promedio, con un rango de 1 a 4, tratados con levodopa más benserazida durante 16 semanas, se observaron efectos motores adversos leves a moderados en 12 casos (44,4 por ciento): 8 pacientes presentaron diskinesias, 7 distonías y un deterioro de final de dosis. La dosis máxima de levodopa ID utilizada fue de 750 mg los que alcanzaron a la tercera semana, previo ascenso paulatino desde 125 mg inicial. Posteriormente, se buscó la mínima dosis efectiva la cual correspondió a una cifra de 475 mg como media con un rango de 250 a 750 mg correspondiente a 49,7 por ciento de reducción, lográndose un efecto antiparkinsoniano similar al obtenido con la dosis máxima. Se discuten los posibles factores que hayan influido en el porcentaje alto de efectos motores adversos encontrados en esta serie